2022 Vol. 7, No. 6

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Research Highlight
Designing gradient solid electrolyte interphase for stable lithium metal batteries
Wenjing Deng, Xiaolei Wang
2022, 7(6): 1129-1131. doi: 10.1016/j.gee.2021.12.005
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The practical application of lithium metal batteries (LMBs) has been impeded by the unstable electrolyte interphase and uncontrollable Li dendrites growth. The structures and components of solid electrolyte interphase (SEI) are extremely important to affect the electrochemical performance of LMBs, but it is hard to regulate them due to the complicated reaction mechanisms. Therein, a gradient SEI layer was designed by adding bisfluoroacetamide into electrolyte, which could guide the uniform deposition of Li ions and suppress the growth of Li dendrites. In addition, this additive also could improve the stability of cathode, resulting in a stable LMBs.
Short Review
Direct conversion of methane to methanol by electrochemical methods
Haomin Jiang, Luting Zhang, Zhiwei Han, Yang Tang, Yanzhi Sun, Pingyu Wan, Yongmei Chen, Morris D. Argyle, Maohong Fan
2022, 7(6): 1132-1142. doi: 10.1016/j.gee.2021.11.007
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A convenient method for methane (CH4) direct conversion to methanol (CH3OH) is of great significance to use methane-rich resources, especially clathrates and stranded shale gas resources located in remote regions. Theoretically, the activation of CH4 and the selectivity to the CH3OH product are challenging due to the extreme stability of CH4 and relatively high reactivity of CH3OH. The state-of-the-art ‘methane reforming - methanol synthesis’ process adopts a two-step strategy to avoid the further reaction of CH3OH under the harsh conditions required for CH4 activation. In the electrochemical field, researchers are trying to develop conversion pathways under mild conditions. They have found suitable catalysts to activate the C–H bonds in methane with the help of external charge and have designed the electrode reactions to continuously generate certain active oxygen species. These active oxygen species attack the activated methane and convert it to CH3OH, with the benefit of avoiding over-oxidation of CH3OH, and thus obtain a high conversion efficiency of CH4 to CH3OH. This mini-review focuses on the advantages and challenges of electrochemical conversion of CH4 to CH3OH, especially the strategies for supplying electro-generated active oxygen species in-situ to react with the activated methane.
Review article
Sprayed separation membranes: A systematic review and prospective opportunities
Guangjin Zhao, Wenjing Han, Liangliang Dong, Hongwei Fan, Zhou Qu, Jiahui Gu, Hong Meng
2022, 7(6): 1143-1160. doi: 10.1016/j.gee.2022.04.001
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Membrane separation technology has been taken up for use in diverse applications such as water treatment, pharmaceutical, petroleum, and energy-related industries. Compared with the design of membrane materials, the innovation of membrane preparation technique is more urgent for the development of membrane separation technology, because it not only affects physicochemical properties and separation performance of the fabricated membranes, but also determines their potential in industrialized application. Among the various membrane preparation methods, spray technique has recently gained increasing attention because of its low cost, rapidity, scalability, minimum of environmental burden, and viability for nearly unlimited range of materials. In this Review article, we summarized and discussed the recent developments in separation membranes using the spray technique, including the fundamentals, important features and applications. The present challenges and future considerations have been touched to provide inspired insights for developing the sprayed separation membranes.
Magic of hydrogen spillover: Understanding and application
Haifang Shen, Hao Li, Zhensheng Yang, Chunli Li
2022, 7(6): 1161-1198. doi: 10.1016/j.gee.2022.01.013
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The hydrogen spillover effect (HSPE) plays an important role in heterogeneous catalysis and hydrogen storage as an interfacial phenomenon, which facilitates the improvement of hydrogen storage properties of porous nanomaterials and indirectly or directly affects the reaction performance of multiphase catalytic reactions. The setting-up of the word “hydrogen spillover” opened up a new area to gain insight into the dynamic behavior of migrating hydrogen atoms on a catalyst surface. However, a comprehensive understanding of the HSPE is still lacking. Today, the development of advanced characterization techniques provides increasingly valuable information to further our understanding of the HSPE. Based on these considerations, in this review, we hope to provide some answers to the question “What is hydrogen spillover and how do we recognize it?”. To do this, we will rely on advanced characterization techniques as well as experimental and theoretical studies. Then, we discuss in detail the influences of the HSPE on hydrogen storage performance and the important catalytic effects of the HSPE in catalysis. These effects will be reviewed by looking through the catalytic results obtained in many reactions in thermal catalysis, electrocatalysis, and photocatalysis. Furthermore, based on the application potential of hydrogen spillover, we present some preliminary research proposals and discuss the opportunities and challenges that remain to be faced in this research area.
Research paper
Novel design and synthesis of 1D bamboo-like CNTs@Sn4P3@C coaxial nanotubes for long-term sodium ion storage
Qianyu Zhang, Yuling Xu, Lifeng Qiu, Axue Liu, Rui Wang, Longhai Zhang, Chaofeng Zhang, Yan-Jie Wang, Jiujun Zhang
2022, 7(6): 1199-1205. doi: 10.1016/j.gee.2021.01.013
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In this work, a novel bamboo-like carbon nanotubes@Sn4P3@carbon (BLCNTs@Sn4P3@C) coaxial nanotubes are designed and prepared using a newly developed hydrothermal method followed by a phophidation process. The prepared Sn4P3 nanoparticles are uniformly coated and wrapped on the one-dimensional (1D) bamboo-like CNTs, which is covered by a uniform carbon layer to form a sandwich-like structure with Sn4P3 in between. The inner CNT and outer carbon can effectively maintain the structural stability and serve as the good electron conductors. Additionally, the outer carbon coating layer can effectively keep BLCNTs@Sn4P3@C nanotubes separate each other, preventing aggregation of Sn4P3 during charge/discharge when this material is used as anode for sodium ion batteries. The anode of BLCNTs@Sn4P3@C shows excellent reversible capacity and a long cycling of over 2000 cycles. The unique design of coaxial nanotubes is greatly beneficial to the electrochemical performance of Sn4P3 for sodium ion storage.
Poly(thiourea triethylene glycol) as a multifunctional binder for enhanced performance in lithium-sulfur batteries
Luke Hencz, Hao Chen, Zhenzhen Wu, Xingxing Gu, Meng Li, Yuhui Tian, Su Chen, Cheng Yan, Abdulaziz S.R. Bati, Joseph G. Shapter, Milton Kiefel, Dong-Sheng Li, Shanqing Zhang
2022, 7(6): 1206-1216. doi: 10.1016/j.gee.2021.01.014
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A mechanically strong binder with polar functional groups could overcome the dilemma of the large volume change during charge/discharge processes and poor cyclability of lithium-sulfur batteries (LSBs). In this work, for the first time, we report the use of poly(thiourea triethylene glycol) (PTTG) as a multifunctional binder for sulfur cathodes to enhance the performance of LSBs. As expected, the PTTG binder facilitates the high performance and stability delivered by the Sulfur-PTTG cathode, including a higher reversible capacity of 825 mAh g-1 at 0.2 C after 80 cycles, a lower capacity fading (0.123% per cycle) over 350 cycles at 0.5 C, a higher areal capacity of 2.5 mAh cm-2 at 0.25 mA cm-2, and better rate capability of 587 mAh g-1 at 2 C. Such superior electrochemical performances could be attributed to PTTG's strong chemical adsorption towards polysulfides which may avoid the lithium polysulfide shuttle effect and excellent mechanical characteristics which prevents electrode collapse during cycling and allows the Sulfur-PTTG electrode to maintain robust electron and ion migration pathways for accelerated redox reaction kinetics.
Deep eutectic solvent strategy enables an octahedral Ni–Co precursor for creating high-performance NiCo2O4 catalyst toward oxygen evolution reaction
Chenyun Zhang, Bingwei Xin, Tingting Chen, Hao Ying, Zhonghao Li, Jingcheng Hao
2022, 7(6): 1217-1227. doi: 10.1016/j.gee.2021.01.017
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Deep eutectic solvents (DESs) have gained much attention in the fabrication of advanced nanoelectrocatalysts due to their amazing template function. However, their stabilizing function for easily hydrolyzed inorganic nanomaterials is rarely studied. Here, a DES-mediated strategy was reported to synthesize octahedral Ni–Co precursor (NiCo–NH3 complex), which could be directly transformed into NiCo2O4 nanooctahedrons after thermal decomposition. The NiCo–NH3 precursor in octahedral shape was achieved with the DES-mediated crystallization in the choline chloride (ChCl)/glycerol. The ChCl/glycerol DES not only tailored the morphology of the as-prepared precursor by template effect but also inhibited its hydrolysis, ensuring the successful fabrication of octahedral NiCo–NH3 complex precursor with high yield. The NiCo–NH3 complex precursor was converted to well-defined NiCo2O4 nanooctahedrons, where the calcination temperature and time were explored in detail. It revealed that DES could participate in the conversion process to control the morphology of calcination product. The resultant NiCo2O4 nanooctahedrons demonstrated excellent electroactivity and remarkable durability for oxygen evolution reaction (OER). The present strategy not only offers an efficient OER electrocatalyst but also enriches the approaches of DESs in designing advanced nanocatalysts.
Engineered NiCo-LDH nanosheets- and ZnFe2O4 nanocubes-decorated carbon nanofiber bonded mats for high-rate asymmetric supercapacitors
Jae-Gyoung Seong, Tae Hoon Ko, Danyun Lei, Woong-Ki Choi, Yun-Su Kuk, Min-Kang Seo, Byoung-Suhk Kim
2022, 7(6): 1228-1240. doi: 10.1016/j.gee.2021.01.015
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In this work, we have prepared the hierarchically nanostructured core–shell NiCo layered double hydroxide (NiCo-LDH) nanosheets- and ZnFe2O4 nanocubes-decorated polyacrylonitrile (PAN)/pitch-based carbon nanofibers (PPCNs) webs (NiCo-LDH@PPCNs as cathode and ZnFe2O4@PPCNs as anode materials) with the bonded network structure by a facile and scalable hydrothemal method. Herein, the low-cost pitch with lower softening point (∼90 °C) as co-precursor was utilized to produce the PAN/pitch-based carbon nanofibers (PPCNs) with enhanced electrical conductivity. The obtained PPCNs with pitch content of 30% (PP30CNs) electrode material delivered higher specific capacitance (∼67 F g-1) than that (∼48 F g-1) of the PAN-based carbon nanofibers (PCNs) at 1 A g-1, due to the increased electrical conductivity and lower interfacial charge transfer resistance (RCT) of ∼0.16 Ω. Further, the NiCo-LDH-decorated PP30CNs (NiCo-LDH@PP30CNs) as cathode material showed superior specific capacitance of 1162 F g-1 at 1.0 A g-1 and ultra-high retention rate of 91.56% at 10 A g-1. The ZnFe2O4@PP30CNs as anode material also showed higher specific capacitance of 282 F g-1 at 1 A g-1 and good rate capability with capacitance retention of 56.73% at 10 A g-1. The as-fabricated asymmetric NiCo-LDH@PP30CNs//ZnFe2O4@PP30CNs hybrid supercapacitor device delivered a specific capacitance of ∼98 F g-1 at 1 A g-1 and excellent capacitance retention of ∼88% after 5000 charge–discharge cycles.
Enhancing the side-chain alkylation of toluene with methanol to styrene over the Cs-modified X zeolite by the assistance of basic picoline as a co-catalyst
Zhe Hong, Guoqing Zhao, Fangtao Huang, Xiaoxia Wang, Zhirong Zhu
2022, 7(6): 1241-1252. doi: 10.1016/j.gee.2021.01.020
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Side-chain alkylation of toluene with methanol is a green pathway to realize the one-step production of styrene under mild conditions, but the low selectivity of styrene is difficult to be improved with by-products of ethylbenzene and xylene. In this study, a new way is introduced to improve the catalytic performance by means of assisting basic compounds as co-catalysts during the toluene side-chain alkylation with methanol to styrene. As a result, high activity of side-chain alkylation appears over the basic Cs-modified zeolite catalysts prepared by ion exchange and impregnation methods. This high performance should be mainly attributed to two co-catalysis actions: (1) the promotion of basic compounds for methanol dehydrogenation to formaldehyde as the intermediate for side-chain alkylation; (2) the suppression of the styrene transfer hydrogenation on basic Cs-modified zeolites to avoid the formation of ethylbenzene. Especially for Cs2O/CsX-ex catalyst, the addition of 2% mol/mol 2-picoline in reaction mixture could achieve both 12.3% toluene conversion and 84.1% styrene selectivity. Whereas the higher concentration of 2-picoline (>6% mol/mol) caused an inhibition to the catalytic activity because the excessive basic compound poisoned the combined acid-base pathway required for the side-chain alkylation process. In addition, two possible side-chain alkylation reaction routes on Cs-modified zeolite under the different 2-picoline absorption were described.
Boosting rate and cycling performance of K-doped Na3V2(PO4)2F3 cathode for high-energy-density sodium-ion batteries
Jiexin Zhang, YangYang Lai, Peng Li, Yanxia Wang, Faping Zhong, Xiangming Feng, Weihua Chen, Jianjun Liu, Xinping Ai, Hanxi Yang, Yuliang Cao
2022, 7(6): 1253-1262. doi: 10.1016/j.gee.2021.01.001
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As a promising cathode material, Na3V2(PO4)2F3 (NVPF) has attracted wide attention for sodium-ion batteries (SIBs) because of its high operating voltage and high structural stability. However, the low intrinsic electronic conductivity and insufficient Na ion mobility of NVPF limit its development. Herein, K-doping NVPF is prepared through a facile ball-milling combined calcination method. The effects of K-doping on the crystal structure, kinetic properties and electrochemical performance are investigated. The results demonstrate that the Na2.90K0.10V2(PO4)3F3 (K0.10-NVPF) exhibits a high capacity (120.8 mAh g-1 at 0.1 C), high rate capability (66 mAh g-1 at 30 C) and excellent cycling performance (a capacity retention of 97.5% at 1 C over 500 cycles). Also, the occupation site of K ions in the lattice, electronic band structure and Na-ion transport kinetic property in K-doped NVPF are investigated by density functional theory (DFT) calculations, which reveals that the K-doped NVPF exhibits improved electronic and ionic conductivities, and located K+ ions in the lattice to contribute to high reversible capacity, rate capability and cycling stability. Therefore, the K-doped NVPF serves as a promising cathode material for high-energy and high-power SIBs.
Enhancing sintering resistance of atomically dispersed catalysts in reducing environments with organic monolayers
Jing Zhang, Chithra Asokan, Gregory Zakem, Phillip Christopher, J. Will Medlin
2022, 7(6): 1263-1269. doi: 10.1016/j.gee.2021.01.022
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Atomically dispersed precious metal catalysts maximize atom efficiency and exhibit unique reactivity. However, they are susceptible to sintering. Catalytic reactions occurring in reducing environments tend to result in atomically dispersed metals sintering at lower temperatures than in oxidative or inert atmospheres due to the formation of mobile metal-H or metal-CO complexes. Here, we develop a new approach to mitigate sintering of oxide supported atomically dispersed metals in a reducing atmosphere using organophosphonate self-assembled monolayers (SAMs). We demonstrate this for the case of atomically dispersed Rh on Al2O3 and TiO2 using a combination of CO probe molecule FTIR, temperature programmed desorption, and alkene hydrogenation rate measurements. Evidence suggests that SAM functionalization of the oxide provides physical diffusion barriers for the metal and weakens the interactions between the reducing gas and metal, thereby discouraging the adsorbate-promoted diffusion of metal atoms on oxide supports. Our results show that support functionalization by organic species can provide improved resistance to sintering of atomically dispersed metals with maintained catalytic reactivity.
Converting furfural residue wastes to carbon materials for high performance supercapacitor
Xiaoying Guo, Xusheng Zhang, Yingxiong Wang, Xiaodong Tian, Yan Qiao
2022, 7(6): 1270-1280. doi: 10.1016/j.gee.2021.01.021
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Sustainable development based on the value-added utilization of furfural residues (FRs) is an effective way to achieve a profitable circular economy. This comprehensive work highlights the potential of FRs as precursor to prepare porous carbons for high performance supercapacitors (SCs). To improve the electrochemical performance of FR-based carbon materials, a facile route based on methanol pretreatment coupled with pre-carbonization and followed KOH activation is proposed. More defects could be obtained after methanol treatment, which is incline to optimize textural structure. The activated methanol treated FR-based carbon materials (AFRMs) possess high specific surface area (1753.5 m2 g-1), large pore volume (0.85 cm3 g-1), interconnected micro/mesoporous structure, which endow the AFRMs with good electrochemical performance in half-cell (326.1 F g-1 at 0.1 A g-1, 189.4 F g-1 at 50 A g-1 in 6 mol L-1 KOH). The constructed symmetric SCs based on KOH, KOH–K3Fe(CN)6 and KOH-KI electrolyte deliver energy density up to 8.9, 9.9 and 10.6 Wh kg-1 with a capacitance retention of over 86% after 10,000 cycles. Furthermore, the self-discharge can be restrained by the addition of K3Fe(CN)6 and KI in KOH electrolyte. This study provides an effective approach for high-valued utilization of FR waste.
Ferric acetylacetonate/covalent organic framework composite for high performance photocatalytic oxidation
Mingzhao Xu, Lifei Liu, Jianling Zhang, Fanyu Zhang, Gang Chen, Qiang Wan, Yufei Sha, Xiuyan Cheng, Zhuizhui Su
2022, 7(6): 1281-1288. doi: 10.1016/j.gee.2021.02.001
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Ferric acetylacetonate/covalent organic framework (Fe(acac)3/COF) composite was synthesized by interfacial polymerization method at room temperature. The crystal structure, morphology and porosity property of the composite were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and nitrogen adsorption. The interaction between Fe(acac)3 and COF was investigated by Fourier transform infrared spectra and X-ray photoelectron spectroscopy. The Fe(acac)3/COF composite was used as a photocatalyst for the oxidation of benzyl alcohol under mild conditions. It exhibits high activity and selectivity for the reaction, of which the mechanism was investigated by determining its photoelectric properties. The Fe(acac)3/COF catalyst developed in this work has application potential in other photocatalytic reactions.
Manganese doping to boost the capacitance performance of hierarchical Co9S8@Co(OH)2 nanosheet arrays
Lingxia Zheng, Weiqing Ye, Pengju Yang, Jianlan Song, Xiaowei Shi, Huajun Zheng
2022, 7(6): 1289-1297. doi: 10.1016/j.gee.2021.02.002
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Transition metal sulfides (TMSs) have been regarded as greatly promising electrode materials for supercapacitors because of abundant redox electroactive sites and outstanding conductivity. Herein, we report a self-supported hierarchical Mn doped Co9S8@Co(OH)2 nanosheet arrays on nickel foam (NF) substrate by a one-step metal–organic-framework (MOF) engaged approach and a subsequent sulfurization process. Experimental results reveal that the introduction of manganese endows improved electric conductivity, enlarged electrochemical specific surface area, adjusted electronic structure of Co9S8@Co(OH)2 and enhanced interfacial activities as well as facilitated reaction kinetics of electrodes. The optimal Mn doped Co9S8@Co(OH)2 electrode exhibits an ultrahigh specific capacitance of 3745 F g-1 at 1 A g-1 (5.618 F cm-2 at 1.5 mA cm-2) and sustains 1710 F g-1 at 30 A g-1 (2.565 F cm-2 at 45 mA cm-2), surpassing most reported values on TMSs. Moreover, a battery-type asymmetric supercapacitor (ASC) device is constructed, which delivers high energy density of 50.2 Wh kg-1 at power density of 800 W kg-1, and outstanding long-term cycling stability (94% capacitance retention after 8000 cycles). The encouraging results might offer an effective strategy to optimize the TMSs for energy-storage devices.
Disposal methods for used passenger car tires: One of the fastest growing solid wastes in China
Biaohua Chen, Dahai Zheng, Ruinian Xu, Shuai Leng, Lili Han, Qianqian Zhang, Ning Liu, Chengna Dai, Bin Wu, Gangqiang Yu, Jie Cheng
2022, 7(6): 1298-1309. doi: 10.1016/j.gee.2021.02.003
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With the rapid growth in the number of passenger cars (PCs) in China over the past decades, more than ten million tons of used tires have already become solid wastes and subsequently caused serious environmental issues. Due to the presence of synthetic rubber in PC tires, waste PC tires cannot be disposed through rubber reclaiming technology. Thus, waste PC tires have become one of fastest growing solid wastes in China. First, the current disposal capacity of the pyrolysis method, regarded as a promising technology for the disposal of waste PC tires, is surveyed and compared with other disposal methods mentioned in previous papers. Second, this work establishes a model to predict the total number of waste PC tires in the next five years depending on the rate of PC growth and current waste tire disposal capacity. Moreover, pyrolysis is evaluated on 15 collected waste PC tires selected from the most representative tire brands in the Chinese market. The corresponding results imply that ∼68.5% of S was into oil and ∼44.3% N and large amount of heavy metals resided in solid carbon which severely limit further applications. Finally, a new pyrolysis technology is introduced that may represent a solution to the limits in the application of tire disposal methods and relief for the coming waste tire crisis.
Biomass-based N doped carbon as metal-free catalyst for selective oxidation of D-xylose into D-xylonic acid
Zengyong Li, Yiming Huang, Xiao Chi, Di Li, Linxin Zhong, Xuehui Li, Chuanfu Liu, Xinwen Peng
2022, 7(6): 1310-1317. doi: 10.1016/j.gee.2021.01.004
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Rational design and facile preparation of low-cost and efficient catalysts for the selective converting of biomass-derived monosaccharides into high value-added chemicals is highly demanded, yet challenging. Herein, we first demonstrate a N doped defect-rich carbon (NC-800-5) as metal-free catalyst for the selective oxidation of D-xylose into D-xylonic acid in alkaline aqueous solution at 100°C for 30 min, with 57.4% yield. The doped graphitic N is found to be the active site and hydroxyl ion participating in the oxidation of D-xylose. Hydroxyl ion and D-xylose first adsorb on NC-800-5 surface, and the aldehyde group of D-xylose is catalyzed to form germinal diols ion. Then, C–H bond break to yield carboxylic group. Furthermore, NC-800-5 catalyst shows high stability in recycled test.
A new perspective on polyethylene-promoted lignin pyrolysis with mass transfer and radical explanation
Yuyang Fan, Chao Liu, Xiangchen Kong, Yue Han, Ming Lei, Rui Xiao
2022, 7(6): 1318-1326. doi: 10.1016/j.gee.2021.02.004
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Co-pyrolysis of lignin and waste plastics, for example polyethylene (PE), has been studied, but related reports are basically on condition optimizations. This study revealed a new perspective on PE-promoted lignin pyrolysis to phenolic monomers with mass transfer and radical explanation. Lignin and PE were first pyrolyzed individually to identify pyrolysis characteristics, pyrolytic products, as well as the suitable co-pyrolysis temperature. Then, co-pyrolysis of blended lignin/PE with various ratios was investigated. Yields of lignin products reached the maximum under lignin/PE ratio of 1:1, but blended approach always inhibited the production of lignin phenols. This resulted from the poor mass transfer and interactions between lignin and PE, in which PE pyrolysates could easily escape from the particle gaps. While in layered approach, PE pyrolysates had to pass through the lignin layer which contributed to the good interactions with lignin pyrolysis intermediates, thus the yields of lignin-derived products were significantly improved. Interactions between lignin and PE (or their pyrolysates) were mainly radical quenching reactions, and X-ray photoelectron spectrum (XPS) and electron paramagnetic resonance (EPR) of pyrolytic chars were conducted to verify these interactions controlled by mass transfer. The percentage of C==C (sp2) and concentration of organic stable radicals in layered lignin/PE char were both the lowest compared with those in blended lignin/PE and lignin char, indicating the stabilization of lignin-derived radicals by PE pyrolysates. Moreover, the spin concentration of radicals in the char from layered char/PE was lower than that in lignin char, which further affirmed the quenching of radicals by PE in the layered co-pyrolysis mode.
Dual-ionic imidazolium salts to promote synthesis of cyclic carbonates at atmospheric pressure
Tengfei Wang, Danning Zheng, Beibei An, Yi Liu, Tiegang Ren, Hans Ågren, Li Wang, Jinglai Zhang, Mårten S.G. Ahlquist
2022, 7(6): 1327-1339. doi: 10.1016/j.gee.2021.02.011
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Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure (0.1 MPa) without any solvent and co-catalyst leading to 96.1% product yield. It can be reused five times to keep the product yield over 90%. These intriguing results are attributed to a new reaction mechanism, which is supported by theoretical calculations along with the measurements of 13C NMR spectrum and Fourier transform infrared spectroscopy (FT-IR). The excellent catalytic activity can be traced to a CO2-philic group along with an electrophilic hydrogen atom. Our work shows that incorporation of CO2-philic group is an feasible pathway to develop the new efficient ionic liquids.
Enhanced catalytic conversion of polysulfides using high-percentage 1T-phase metallic WS2 nanosheets for Li–S batteries
Changyu Yang, Ning Gong, Tao Chen, Yang Li, Wenchao Peng, Fengbao Zhang, Xiaobin Fan
2022, 7(6): 1340-1348. doi: 10.1016/j.gee.2021.03.001
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High-energy-density lithium-sulfur batteries has attracted substantial attention as competitive candidates for large-scale energy storage technologies. Still, the adverse “shuttle effect” and sluggish sulfur conversion reaction kinetics immensely obstruct their commercial viability. Herein, a two-dimensional metallic 1T phase WS2 (1T-WS2) nanosheets modified functional separator is developed to improve the electrochemical performance. Meanwhile, the semiconducting bulk-WS2 crystals, and 2H phase WS2 (2H-WS2) nanosheets with more basal-plane S-vacancy defects are also prepared to probe the contributions of the crystal structure (phase), S-vacancy defects, and edges to the Li–S batteries performance experimentally and theoretically. In merits of the synergistic effect of high ion and electron conductivity, enhanced binding ability to lithium polysulfides (LiPSs), and sufficient electrocatalytic active sites, the 1T-WS2 shows highly efficient electrocatalysis of LiPSs conversion and further improves Li–S battery performance. As expected, thus-fabricated cells with 1T-WS2 nanosheets present superior cycle stability that maintain capacity decline of 0.039% per cycle after 1000 cycles at 1.0 C. The strategy presented here offers a viable approach to reveal the critical factors for LiPSs catalytic conversion, which is beneficial to developing advanced Li–S batteries with enhanced properties.
Pt–Pd bimetallic nanoparticles anchored on uniform mesoporous MnO2 sphere as an advanced nanocatalyst for highly efficient toluene oxidation
Jiaqin He, Dongyun Chen, Najun Li, Qingfeng Xu, Hua Li, Jinghui He, Jianmei Lu
2022, 7(6): 1349-1360. doi: 10.1016/j.gee.2021.03.002
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Improving catalytic performance is a yet still challenge in thermal catalytic oxidation. Herein, uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO2 template strategy for the total catalytic degradation of volatile organic compounds at low temperature. The introduction of mesopores into the MnO2 support induces a large specific surface area and pore size, thus providing numerous accessible active sites and enhanced diffusion properties. Moreover, the addition of a secondary noble metal can adjust the Oads/Olatt molar ratios, resulting in high catalytic activity. Among them, the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 mL g-1 h-1, reaching 100% toluene oxidation at 175 °C with a lower activation energy (57.0 kJ mol-1) than the corresponding monometallic Pt or non-Pt-based catalysts (93.8 kJ mol-1 and 214.2 kJ mol-1). Our findings demonstrate that the uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.
Green and selective hydrogenation of aromatic diamines over the nanosheet Ru/g-C3N4-H2 catalyst prepared by ultrasonic assisted impregnation-deposition method
Huanhuan Yang, Liguo Wang, Shuang Xu, Yan Cao, Peng He, Jiaqiang Chen, Zheng Zheng, Huiquan Li
2022, 7(6): 1361-1376. doi: 10.1016/j.gee.2021.01.003
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In this study, nanosheet g-C3N4-H2 was prepared by thermal exfoliation of bulk g-C3N4 under hydrogen. A series of Ru/g-C3N4-H2 catalysts with Ru species supported on the nanosheet g-C3N4-H2 were synthesized via ultrasonic assisted impregnation-deposition method. Ultrafine Ru nanoparticles (<2 nm) were highly dispersed on nanosheet g-C3N4-H2. Strong interaction due to Ru-Nx coordination facilitated the uniform distribution of Ru species. Meanwhile, the involvement of surface basicity derived from abundant nitrogen sites was favourable for enhancing the selective hydrogenation performance of bi-benzene ring, i.e., almost complete 4,4′-diaminodiphenylmethane (MDA) conversion and >99% 4,4′-diaminodicyclohexylmethane selectivity, corresponding to a reaction activity of 35.7 molMDA molRu-1 h-1. Moreover, the reaction activity of catalyst in the fifth run was 36.5 molMDA molRu-1 h-1, which was comparable with that of the fresh one. The computational results showed that g-C3N4 as support was favorable for adsorption and dissociation of H2 molecules. Moreover, the substrate scope can be successfully expanded to a variety of other aromatic diamines. Therefore, this work provides an efficient and green catalyst system for selective hydrogenation of aromatic diamines.
Double Z-Scheme g-C3N4/BiOI/CdS heterojunction with I3-/I- pairs for enhanced visible light photocatalytic performance
Yan Zhang, Yixiao Wu, Liang Wan, Wenfeng Yang, Huijun Ding, Chongyang Lu, Weihao Zhang, Zipeng Xing
2022, 7(6): 1377-1389. doi: 10.1016/j.gee.2021.08.004
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The g-C3N4/BiOI/CdS double Z-scheme heterojunction photocatalyst with I3-/I- redox pairs is prepared using simple calcination, solvothermal, and solution chemical deposition methods. The photocatalyst comprised mesoporous, thin g-C3N4 nanosheets loaded on flower-like microspheres of BiOI with CdS quantum dots. The g-C3N4/BiOI/CdS double Z-scheme heterojunction has abundant active sites and in situ redox I3-/I- mediators and shows quantum size effects, which are all conducive to enhancing the separation of photoinduced charges and increasing the photocatalytic degradation efficiency for bisphenol A, a model pollutant. Specifically, the heterojunction photocatalyst achieves a photocatalytic degradation efficiency for bisphenol A of 98.62% in 120 min and photocatalytic hydrogen production of 863.44 μmol h-1g-1 on exposure to visible light. The excellent visible-light photocatalytic performance is as a result of the Z-scheme heterojunction, which extends absorption to the visible light region, as well as the I3-/I- pairs, which accelerate photoinduced charge carrier transfer and separation, thus dramatically boosting the photocatalytic performance. In addition, the key role of the charge transfer across the indirect Z-scheme heterojunction has been elucidated and the transfer mechanism is confirmed based on the detection of intermediate I3- ions. Thus, this study provides guidelines for the design of indirect Z-scheme heterojunction photocatalysts.
Electron promoted ZnO for catalytic synthesis of higher alcohols from syngas
Fang Li, Qian Zhang, Jing Liu, Nan Cui, Guoqing Guan, Wei Huang
2022, 7(6): 1390-1400. doi: 10.1016/j.gee.2022.01.015
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Abstract:
Direct conversion of syngas from those non-petroleum carbon resources to higher alcohols are very attractive due to the process simplicity with low energy consumption. However, the reaction always suffers from low yield as well as low selectivity. Herein, effective increase of higher alcohols proportion in the product is realized by direct conversion of syngas over electronically-modulated ZnO semiconductor via Cu doping. It is considered that the lower Fermi level and narrower band gap of catalysts by embedding Cu2+ into ZnO lattice could facilitate donor reaction by boosting the process for the reactants to obtain electrons on the catalyst surface for the formation of CHx species and carbon chain growth, in which the Cu doping on ZnO lattice play important role in the promotion of CO adsorption. As a result, 4 mol% Cu doped ZnO exhibits a highest C2+OH/ROH fraction of 48.1%. Selectivity of catalysts from straight chain alcohol is better than from branch chain alcohol, which is different from promoted Cu/ZnO based catalyst. However, over-doping of Cu (7 mol%) on ZnO results in the aggregation Cu species on ZnO surface, leading to a sharp decrease of higher alcohols proportion to 3.2%. The results shed light on the nature that a direct correlation between semiconductor Fermi level and synthesis of higher alcohols, and the semiconductor-based catalysts mainly accelerate the hydrogenation reactions by enhancing thermally excited electron transfer.
Ultrafast battery heat dissipation enabled by highly ordered and interconnected hexagonal boron nitride thermal conductive composites
Zhuoya Wang, Kaihang Zhang, Bing Zhang, Zheming Tong, Shulan Mao, Hao Bai, Yingying Lu
2022, 7(6): 1401-1410. doi: 10.1016/j.gee.2022.02.007
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Abstract:
Heat dissipation involved safety issues are crucial for industrial applications of the high-energy density battery and fast charging technology. While traditional air or liquid cooling methods suffering from space limitation and possible leakage of electricity during charge process, emerging phase change materials as solid cooling media are of growing interest. Among them, paraffin wax (PW) with large latent heat capacity and low cost is desirable for heat dissipation and thermal management which mainly hindered by their relatively low thermal conductivity and susceptibility to leakage. Here, highly ordered and interconnected hexagonal boron nitride (h-BN) networks were established via ice template method and introduced into PW to enhance the thermal conductivity. The composite with 20 wt% loading amount of h-BN can guarantee a highly ordered network and exhibited high thermal conductivity (1.86 W m-1 K-1) which was 4 times larger compared with that of random dispersed h-BN involved PW and nearly 8 times larger compared with that of bare PW. The optimal thermal conductive composites demonstrated ultrafast heat dissipation as well as leakage resistance for lithium-ion batteries (LIBs), heat generated by LIBs can be effectively transferred under the working state and the surface temperature kept 6.9 °C lower at most under 2–5 °C continuous charge-discharge process compared with that of bare one which illustrated great potential for industrial thermal management.

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