2019 Vol. 4, No. 3

column
  Previous Issue | Next Issue 
Display Method:
Cover info & Content
Editorial
Catalysis for sustainability
2019, 4(3) doi: 10.1016/j.gee.2019.07.001
Abstract HTML PDF
Abstract:
Research highlight
Atomically dispersed Fe atoms anchored on N-doped carbon hollow nanospheres boost the electrocatalytic performance for oxygen reduction reaction
Danye Liu, Dong Chen, Jun Yang
2019, 4(3): 208-209. doi: 10.1016/j.gee.2019.07.002
Abstract HTML PDF
Abstract:
Review article
Applications of lignin-derived catalysts for green synthesis
Yuting Zhu, Zhijing Li, Jinzhu Chen
2019, 4(3): 210-244. doi: 10.1016/j.gee.2019.01.003
Abstract HTML PDF
Abstract:
This review intends to introduce the application of lignin-derived catalyst for green organic synthesis over latest two decades and aims to present a renewable alternative for conventional catalyst for future industry application. The structure of lignin is initially introduced in this review. Then, various pretreatment and activation technologies of lignin are systematically presented, which includes physical activation for the formation of well-developed porosity and chemical activation to introduce catalytic active sites. Finally, the catalytic performances of various lignin-derived catalysts are rationally assessed and compared with conventional catalysts, which involves lignin-derived solid acids for hydrolysis, hydration, dehydration (trans)esterification, multi-component reaction and condensation, lignin-derived solid base for Knoevenagel reaction, lignin-derived electro-catalysts for electro-oxidation, oxygen reduction reaction, and lignin-derived supported transition metal catalysts for hydrogenation, oxidation, coupling reaction, tandem reaction, condensation reaction, ring-opening reaction, Friedel-Crafts-type reaction, Fischer–Tropsch synthesis, click reaction, Glaser reaction, cycloaddition and (trans)esterification. The above lignin-derived catalysts thus successfully promote the transformations of organic compounds, carbon dioxide, biomass-based cellulose, saccharide and vegetable oil into valuable chemicals and fuels. At the end of this review, some perspectives are given on the current issues and tendency on the lignin-derived catalysts for green chemistry.
Short communication
Construction of highly-stable graphene hollow nanospheres and their application in supporting Pt as effective catalysts for oxygen reduction reaction
Huaifang Zhang, Jubing Zhang, Kunhao Liu, Yunqi Zhu, Xiaoyu Qiu, Dongmei Sun, Yawen Tang
2019, 4(3): 245-253. doi: 10.1016/j.gee.2018.12.002
Abstract HTML PDF
Abstract:
The construction and surface modification of three-dimensional (3D) graphene structures have been recognized as effective ways to prepare high-performance graphene-based composites in energy-related applications. Herein, on the basis of well-defined morphology and efficient electron conduction, the 3D highly-stable graphene hollow nanospheres have been synthesized by using sacrificial template method. The as-prepared 3D graphene nanospheres exhibit superior mechanical stability, electrochemical stability, and strong hydrophobicity, which may accelerate the emission of H2O in acidic medium-based ORR. Accordingly, the 3D highly-stable graphene nanospheres are used to confine tiny Pt nanoparticles (3D r-GO@Pt HNSs) for ORR in acidic medium, exhibiting superior activity with 4-electron-transfered pathway. Meanwhile, dramatically improved durability are achieved in terms of both ORR mass activity and electrochemically surface area compared to those of commercial Pt/C.
Research paper
Rough-surfaced bimetallic copper–palladium alloy multicubes as highly bifunctional electrocatalysts for formic acid oxidation and oxygen reduction
Dong Chen, Linlin Xu, Hui Liu, Jun Yang
2019, 4(3): 254-263. doi: 10.1016/j.gee.2018.09.002
Abstract HTML PDF
Abstract:
Engineering the morphology of nanomaterials and modifying their electronic structure are effective ways to improve their performance in electrocatalysis. Through combining the co-reduction of Pd2+ and Cu2+ precursors with a digestive ripening process in oleylamine, we report the synthesis of copper-palladium (CuPd) alloy multicubes with rough surfaces. Benefiting from their alloy and unique rough-surfaced structure, which provides ample edge/corner and step atoms as well as the electronic coupling between Cu and Pd leading to the lower of d-band center, the rough-surfaced CuPd alloy multicubes show much better electrocatalytic performance not only for formic acid oxidation but also for oxygen reduction in comparison with those of spherical CuPd alloy nanoparticles and commercial Pd/C catalyst. In contrast, we confirm that the rough-surfaced CuPd alloy multicubes only exhibit very low Faradaic efficiency (34.3%) for electrocatalytic conversion of carbon dioxide (CO2) to carbon monoxide (CO) due to the presence of strong competing hydrogen evolution reaction, which results in their very poor selectivity for the reduction of CO2 to CO. The findings in this study not only offer a promising strategy to produce highly effective electrocatalysts for direct formic acid fuel cells, but also enlighten the ideas to design efficient electrocatalysts for CO2 reduction.
Bandgap engineering of hierarchical network-like SnIn4S8 microspheres through preparation temperature for excellent photocatalytic performance and high stability
Jie Wang, Min Liu, Mei Wang, Yi Wang, Aiting Zhang, Xiang Zhao, Guisheng Zeng, Fang Deng
2019, 4(3): 264-269. doi: 10.1016/j.gee.2019.04.002
Abstract HTML PDF
Abstract:
The effect of synthesis temperature and reaction time on the visible-light photocatalytic activity of hierarchical network-like SnIn4S8 microspheres was investigated by the low-temperature co-precipitation strategy. The preparation temperature and reaction time have great influence on the photocatalytic activity of SnIn4S8, and the optimal preparation temperature and reaction time are 70 °C and 3 h, respectively. The SnIn4S8 shows good reusability and high stability with no observable decrease of photocatalytic activity in five consecutive cycles.
Anion intercalated layered-double-hydroxide structure for efficient photocatalytic NO remove
Wangchen Huo, Tong Cao, Xiaoying Liu, Weina Xu, Biqin Dong, Yuxin Zhang, Fan Dong
2019, 4(3): 270-277. doi: 10.1016/j.gee.2018.11.001
Abstract HTML PDF
Abstract:
Due to the easily controllable interlayer anions, metal cation composition proportion and thickness, which is beneficial to modify surface chemical state and tune bandgap, layered double hydroxides (LDHs) have great promising potential for photocatalytic applications. In this study, we have successfully synthesized the ZnAl–LDH intercalated the single anion between ZnAl cationic interlayer without anionic impurities by using a facile calcining and reconstructing routes. The electron structure and surface chemical state of the prepared products have been investigated by combining the DFT calculation and experimental characterization methods. UV–vis DRS was used to certify the light absorption of the prepared products, and we performed the DFT calculation to demonstrate the density of state and activation of reactant. These results suggested that the ZnAl–LDH–CO3 possessed the more proper band structure and superior ability to activate NO and O2 for accelerating the photocatalytic NO oxidation activity. Moreover, the in situ DRIFTS with dynamically monitoring intermediates and products over the ZnAl–LDH–CO3 was adopted to declare the photocatalytic NO oxidized process during the photocatalytic reaction process. This work illustrated the influence of different interlayer anions to the electron structure and surface chemical state of ZnAl–LDH structure through the experimental verification combined DFT calculation and the photocatalytic NO oxidized process viain situ DRIFTS analyzing, which would provide a novel way to design and fabricate the efficient photocatalysis, and understand the reaction process.
Template-free synthesis of hollow TiO2 nanospheres supported Pt for selective photocatalytic oxidation of benzyl alcohol to benzaldehyde
Hongbing Song, Zong Liu, Yongjie Wang, Na Zhang, Xiaofei Qu, Kai Guo, Meng Xiao, Hengjun Gai
2019, 4(3): 278-286. doi: 10.1016/j.gee.2018.09.001
Abstract HTML PDF
Abstract:
Heterogeneous photocatalytic system are widely applied to degrade organic pollutants or converse into high value-added chemicals. Both environmental and energy aspects should be considered to improve these chemical processes, favoring reaction conditions that involve room temperature and ambient O2 pressure. In the present work, hollow titanium dioxide nanospheres were fabricated via template-free method. The prepared samples were characterized by X-ray diffraction, N2 adsorption–desorption isotherms, transmission electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity was evaluated by photocatalytic oxidation of benzyl alcohol to benzaldehyde with visible light under atmospheric pressure at room temperature. The designed hollow structure (2%Pt–TiO2–5) not only exhibited a very high surface area, but also promoted photonic behavior and multiple light scattering, which as an efficient photocatalyst performed moderate conversion (about 20%) and high selectivity (> 99%) for oxidation of benzyl alcohol to benzaldehyde at room temperature with visible light in solvent of toluene. This work suggests that both hollow structure and Pt nanoparticles have great potential for execution of oxidative transformations under visible light.
Influence of the preparation method on the catalytic activity of MgAl hydrotalcites as solid base catalysts
Sungjae Park, Dahye Kwon, Ji Yeon Kang, Ji Chul Jung
2019, 4(3): 287-292. doi: 10.1016/j.gee.2018.11.003
Abstract HTML PDF
Abstract:
MgAl hydrotalcites were synthesized using different preparation methods (a co-precipitation method, a urea method, and a simple one) to analyze their effect on the catalytic activity of these solid base catalysts. The method strongly affected the structure of their layers (e.g., the growth and stacking of the layers, and the type of intercalated anions) and, accordingly, their catalytic activity. The MgAl hydrotalcite prepared by co-precipitation showed the best catalytic performance in the isomerization of glucose into fructose, due to the small crystallite size and sand rose morphology enhancing the exposure of surface active sites to reactants.
In-situ generated ionic liquid catalyzed aldol condensation of trioxane with ester in mild homogeneous system
Gang Wang, Zengxi Li, Chunshan Li, Suojiang Zhang
2019, 4(3): 293-299. doi: 10.1016/j.gee.2018.11.004
Abstract HTML PDF
Abstract:
α, β-unsaturated esters were often synthesized from aldehydes and esters in the presence of strong organic base that was very sensitive to air and moisture via aldol reaction. Trioxane was very useful C1 resource, however, the decomposition of it was always the challenging problem that facing researchers. Herein, a novel synthetic methodology for α, β-unsaturated ester preparation from trioxane and ester with mild catalysis of generated ammonium trifluoromethanesulfonate ionic liquid. The enolization of ester as well as the decomposition of trioxane could proceed easily in the presence of boryl trifluoromethanesulfonate and amine at 20–25 °C. Then the enolate and decomposed formaldehyde occurs aldol reaction to form α, β-unsaturated ester. With this strategy, the yield and selectivity of product from various substrates including aliphatic esters, lactones and thioester could reach up to 85.2% and 90.1%.
Improvement of low temperature activity and stability of Ni catalysts with addition of Pt for hydrogen production via steam reforming of ethylene glycol
Xingling Zhao, Kai Wu, Weiping Liao, Yingxiong Wang, Xiaoning Hou, Mingshan Jin, Zhanghuai Suo, Hui Ge
2019, 4(3): 300-310. doi: 10.1016/j.gee.2018.11.002
Abstract HTML PDF
Abstract:
Hydrogen production by steam reforming of ethylene glycol (EG) at 300 °C was investigated over SiO2 and CeO2 supported Pt–Ni bimetallic catalysts prepared by incipient wetness impregnation methods. It was observed that impregnation sequence of Pt and Ni can affect the performance of catalysts apparently. Catalyst with Pt first and then Ni addition showed higher EG conversion and H2 yield owing to the Ni enrichment on the surface and the proper interaction between Pt and Ni. It was observed that although SiO2 supported catalysts exhibited better activity and H2 selectivity, CeO2 supported ones had better stability. This is attributed to the less coke formation on CeO2. Increasing Pt/Ni ratio enhanced the reaction activity, and Pt3–Ni7 catalysts with 3 wt% Pt and 7 wt% Ni showed the highest activity and stability. Ni surficial enrichment facilitated the C—C bond rupture and water gas shift reactions; and Pt addition inhibited methanation reaction. Electron transfer and hydrogen spillover from Pt to Ni suppressed carbon deposition. These combined effects lead to the excellent performance of Pt3–Ni7 supported catalysts.
Enhanced selective catalytic reduction of NO with NH3 via porous micro-spherical aggregates of Mn–Ce–Fe–Ti mixed oxide nanoparticles
Junqi Tian, Ke Zhang, Wei Wang, Fu Wang, Jianming Dan, Shengchao Yang, Jinli Zhang, Bin Dai, Feng Yu
2019, 4(3): 311-321. doi: 10.1016/j.gee.2019.05.001
Abstract HTML PDF
Abstract:
We rationally designed a high performance denitration (De-NOx) catalyst based on a micrometer-sized spherical Mn–Ce–Fe–Ti (CP-SD) catalyst for selective catalytic reduction (SCR). This was prepared by a co-precipitation and spray drying (CP-SD) method. The catalyst was systematically characterized, and its morphological structure and surface properties were identified. Compare with conventional Mn–Ce–Fe–Ti (CP) catalysts, the Mn–Ce–Fe–Ti (CP-SD) catalyst had superior surface-adsorbed oxygen leading to enhanced “fast NH3-SCR” reaction. The as-obtained Mn–Ce–Fe–Ti (CP-SD) catalyst offered excellent NO conversion and N2 selectivity of 100.0% and 84.8% at 250 °C, respectively, with a gas hourly space velocity (GHSV) of 40,000 h−1. The porous micro-spherical structure provides a larger surface area and more active sites to adsorb and activate the reaction gases. In addition, the uniform distribution and strong interaction of manganese, iron, cerium, and titanium oxide species improved H2O and SO2 resistance. The results showed that the Mn–Ce–Fe–Ti (CP-SD) catalyst could be used prospectively as a denitration (De-NOx) catalyst.
Well-dispersive K2O-KCl alkaline catalyst derived from waste banana peel for biodiesel synthesis
Mingming Fan, Hao Wu, Min Shi, Pingbo Zhang, Pingping Jiang
2019, 4(3): 322-327. doi: 10.1016/j.gee.2018.09.004
Abstract HTML PDF
Abstract:
In this work, a novel alkaline catalyst was synthesized by an economical and effective method of roasting waste banana peel. From XRD, FT-IR, SEM, EDS, TGA and CO2-TPD characterization, it was proved that the calcined banana peel catalyst showed the strong alkalinity and well dispersity in microstructure, and K2OKCl as the main active contents. The calcined banana peel catalyst showed better catalytic performance than the catalysts by physical mixing of K2O and KCl, which was due to good dispersibility of K2OKCl formed during decomposing of carbon fiber by calcination of banana peel. Furthermore, the calcined banana peel catalyst also performed well in both water-resistant ability and recyclability, indicating their potential for biodiesel production from an efficient, robust, and low-cost catalyst.
A kinetic model for a single step biodiesel production from a high free fatty acid (FFA) biodiesel feedstock over a solid heteropolyacid catalyst
Aashish Gaurav, Stéphane Dumas, Chau T.Q. Mai, Flora T.T. Ng
2019, 4(3): 328-341. doi: 10.1016/j.gee.2019.03.004
Abstract HTML PDF
Abstract:
Production of biodiesel from yellow grease (waste cooking oil and waste animal fats) is fast emerging as a promising alternative to address the twin challenges before the biodiesel industry today-fluctuation in prices of vegetable oil and the food versus fuel debate. Yellow grease has a high percentage of free fatty acids (FFA) and proves to be an unsuitable feedstock for biodiesel production from commercially viable alkali-catalyzed production systems due to saponification problems. “Green” methodologies based on heterogeneous solid acid catalyzed reactions have the potential to simultaneously promote esterification and transesterification reactions of yellow grease to produce biodiesel without soap formation and offer easy catalyst separation without generation of toxic streams. This paper presents kinetic studies for the conversion of model yellow grease feeds to biodiesel using a heteropolyacid supported on alumina (HSiW/Al2O3) using a batch autoclave. Three model yellow grease feeds were prepared using canola oil with added FFA such as palmitic, oleic and linoleic acid. A pseudo homogeneous kinetic model for the parallel esterification and transesterification was developed. The rate constants and activation parameters for esterification and transesterification reactions for the model yellow grease feeds were determined. The rate constants for esterification are higher than the transesterification rate constants. The kinetic model was validated using the experimental biodiesel data obtained from processing a commercial yellow grease feed. The kinetic model could be used to design novel processes to convert various low-value waste oils, fats and non-food grade oils to sustainable biodiesel.

Publish With GEE

Contact

  • Email：gee@ipe.ac.cn
  • Tel：010-82627075
  • Address：North 2nd street, Zhongguancun, Haidian District, Beijing, China

Links

京ICP备10002620号-1京公网安备 11010802039050号

Supported by: Beijing Renhe Information Technology Co. Ltd