2018 Vol. 3, No. 4

column
  Previous Issue | Next Issue 
Display Method:
Cover info & Content
Editorial
Catalysis for sustainability
2018, 3(4) doi: 10.1016/j.gee.2018.09.003
Abstract HTML PDF
Abstract:
Short communication
Freestanding Pt nanosheets with high porosity and improved electrocatalytic performance toward the oxygen reduction reaction
Chuang Fan, Zihan Huang, Xianyu Hu, Zhaoping Shi, Tianyang Shen, Yawen Tang, Xiaojun Wang, Lin Xu
2018, 3(4): 310-317. doi: 10.1016/j.gee.2018.05.002
Abstract HTML PDF
Abstract:
Because of the intriguing electronic properties, high specific surface areas and confinement effect, two-dimensional (2D) noble metal nanosheets usually exhibit fascinating physicochemical properties and thus hold great promises in fuel cell devices and beyond. Herein, 2D porous Pt nanosheets composed by interweaved ultrathin nanowires are successfully fabricated via a facile NaCl-templated process. Controlled experiments demonstrate that the adoption of NaCl and appropriate ratio of NaCl and Pt precursor are indispensable for the formation of porous Pt nanosheets. Impressively, the cost-effective NaCl template can be recyclable through a simple recrystallization procedure, which may greatly reduce the synthetic cost. By virtue of their structural merits, including high porosity, 2D anisotropy and abundant defects, the resultant porous Pt nanosheets exhibit superior activity and enhanced stability towards the oxygen reduction reaction (ORR) compared to the commercial Pt black in alkaline medium. The present study not only offers a high-performance electrocatalyst for fuel cell devices, but also provides a new perspective toward the rational synthesis of 2D noble metal nanosheets with high porosity and diverse functionalities.
Short Review
Shell biorefinery: A comprehensive introduction
Max J. Hülsey
2018, 3(4): 318-327. doi: 10.1016/j.gee.2018.07.007
Abstract HTML PDF
Abstract:
Biomass refinery is considered to be a key technology in the 21st century due to the importance of the sustainable production of various bio-derived fuels and fine chemicals. Besides the synthesis of oxygen-containing chemicals mainly from lignocellulosic biomass, nitrogen-containing chemicals belong to some of the most important commodity and fine chemicals. In this introductory short review, the main similarities and difficulties between petroleum oil- and biorefinery will be discussed and future challenges will be highlighted. As a particular example, recent developments in the shell biorefinery – the utilization of shell waste – will be reviewed. Particular emphasis will be placed on the structure of shell biomass, the current and emerging fractionation methods and the conversion of chitin and chitosan to various heteroatom-containing chemicals. This review is meant to provide an introduction to beginners in the field of biorefinery as well as a comprehensive discussion of recent proceedings in the field of shell biorefinery. An outlook on the future potential and challenges will be given.
Catalytic transfer hydrogenolysis as an efficient route in cleavage of lignin and model compounds
Jiaguang Zhang
2018, 3(4): 328-334. doi: 10.1016/j.gee.2018.08.001
Abstract HTML PDF
Abstract:
Cleavage of aromatic ether bonds through hydrogenolysis is one of the most promising routes for depolymerisation and transformation of lignin into value-added chemicals. Instead of using pressurized hydrogen gas as hydrogen source, some reductive organic molecules, such as methanol, ethanol, isopropanol as well as formates and formic acid, can serve as hydrogen donor is the process called catalytic transfer hydrogenolysis. This is an emerging and promising research field but there are very few reports. In this paper, a comprehensive review of the works is presented on catalytic transfer hydrogenolysis of lignin and lignin model compounds aiming to breakdown the aromatic ethers including α-O-4, β-O-4 and 4-O-5 linkages, with focus on reaction mechanisms. The works are organised regarding to different hydrogen donors used, to gain an in-depth understanding of the special role of various hydrogen donors in this process. Perspectives on current challenges and opportunities of future research to develop catalytic transfer hydrogenolysis as a competitive and unique strategy for lignin valorisation are also provided.
Review article
Electrocatalysts based on metal@carbon core@shell nanocomposites: An overview
Yi Peng, Shaowei Chen
2018, 3(4): 335-351. doi: 10.1016/j.gee.2018.07.006
Abstract HTML PDF
Abstract:
Developing low-cost, high-performance catalysts is of fundamental significance for electrochemical energy conversion and storage. In recent years, metal@carbon core@shell nanocomposites have emerged as a unique class of functional nanomaterials that show apparent electrocatalytic activity towards a range of reactions, such as hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, and CO2 reduction reaction, that are important in water splitting, fuel cells and metal-air batteries. The activity is primarily attributed to interfacial charge transfer from the metal core to the carbon shell that manipulate the electronic interactions between the catalyst surface and reaction intermediates, and varies with the structures and morphologies of the metal core (elemental composition, core size, etc.) and carbon shell (doping, layer thickness, etc.). Further manipulation can be achieved by the incorporation of a third structural component. A perspective is also included highlighting the current gap between theoretical modeling and experimental results, and technical challenges for future research.
Research paper
Engineering porosity into trimetallic PtPdNi nanospheres for enhanced electrocatalytic oxygen reduction activity
Chunjie Li, You Xu, Yinghao Li, Hongjie Yu, Shuli Yin, Hairong Xue, Xiaonian Li, Hongjing Wang, Liang Wang
2018, 3(4): 352-359. doi: 10.1016/j.gee.2018.07.004
Abstract HTML PDF
Abstract:
Platinum (Pt)-based multi-metallic nanostructures show great promise as electrocatalysts for the oxygen reduction reaction (ORR) in fuel cell cathodes. Herein, we report a simple, one-step surfactant-directed synthetic strategy to directly synthesize tri-metallic PtPdNi mesoporous nanospheres (PtPdNi MNs) in a high yield. The synthesis could be accomplished in aqueous solution at mild reaction temperature (40 °C) without needing any organic solvent, yielding well-dispersed PtPdNi MNs with uniform shape and narrow size distribution. Benefitting from their unique mesoporous and highly open structure and tri-metallic composition, the as-synthesized PtPdNi MNs demonstrate superior catalytic activity and stability for ORR in acidic solution in comparison with PtPdNi nanodendrites (PtPdNi NDs), PtPd MNs and commercial Pt/C catalyst. The present approach may open a reliable path to the design of advanced electrocatalysts with desired performance.
Preparation and characterization of bimetallic Pt^Ni-P/CNT catalysts via galvanic displacement reaction on electrolessly-plated Ni-P/CNT
Yangcheng Jiang, Zhen Liu, Jili Song, Ikwhang Chang, Jianhuang Zeng
2018, 3(4): 360-367. doi: 10.1016/j.gee.2018.07.005
Abstract HTML PDF
Abstract:
Platinum-based bimetallic catalysts have broad applications in polymer electrolyte membrane fuel cells and water splitting. In this work, galvanic displacement reaction was employed to prepare Pt^Ni-P/CNT catalysts using electrolessly-plated Ni-P/CNT. These catalysts were extensively characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Catalytic activities towards methanol oxidation and hydrogen evolution reactions were evaluated and benchmarked with a commercial Pt/C catalyst. Uniform dispersion of Pt on Ni-P particles led to high Pt utilization, and the electrochemical surface area of Pt^Ni-P/CNT with 12.1% Pt loading was found to be 126 m2 g−1, higher than that of a commercial Pt/C (77.9 m2 g−1). The Tafel slopes for the Pt^Ni-P/CNT catalysts were also found to be smaller than that of Pt/C indicating faster kinetics for hydrogen evolution reaction.
Popping of g-C3N4 mixed with cupric nitrate: Facile synthesis of Cu-based catalyst for construction of CN bond
Shaoyu Yuan, Penglei Cui, Yunrui Zhang, Hong Zhang, Li Huo, Yongjun Gao
2018, 3(4): 368-374. doi: 10.1016/j.gee.2018.08.003
Abstract HTML PDF
Abstract:
A novel strategy to synthesize copper-based nanoparticles supported on carbon nitride (C3N4) was developed by popping of mixture containing C3N4 and cupric nitrate. Characterizations such as X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) indicate that the structure of g-C3N4 maintained although a popping process occurred. High resolution transmission electronic microscopy (HRTEM) characterization illustrated that copper-based nanoparticles with diameter of < 1 nm were well distributed on g-C 3N4. This kind of copper catalyst exhibits high catalytic activity and selectivity in arylation of pyrazole, a simple and effect strategy to construct CN bond in organic chemistry. According to the results of control experiments and characterizations, cuprous oxide should be the catalytic active phase in the supported coper-based catalyst.
Reduced graphene oxide supported PdNi alloy nanocrystals for the oxygen reduction and methanol oxidation reactions
Hui-Min Liu, Shu-He Han, Ying-Ying Zhu, Pei Chen, Yu Chen
2018, 3(4): 375-383. doi: 10.1016/j.gee.2018.06.003
Abstract HTML PDF
Abstract:
The research on electrocatalysts with relatively lower price than Pt and excellent electrocatalytic performance for the cathode oxygen reduction reaction (ORR) and anode methanol oxidation reaction (MOR) is vital for the development of direct methanol fuel cells (DMFCs). In this work, we develop a cyanogel-reduction method to synthesize reduced graphene oxide (rGO) supported highly dispersed PdNi alloy nanocrystals (PdNi/rGO) with high alloying degree and tunable Pd/Ni ratio. The large specific surface area and the d-band center downshift of Pd result in excellent activity of Pd4Ni1/rGO nanohybrids for the ORR. The modification of Pd electronic structure can facilitate the adsorption of CH3OH on Pd surface and the highly oxophilic property of Ni can eliminate/mitigate the COads intermediates poisoning, which make PdNi/rGO nanohybrids possess superior MOR activity. In addition, rGO improve the stability of PdNi alloy nanocrystals for the ORR and MOR. Due to high activity and stability for the ORR and MOR, PdNi/rGO nanohybrids are promising to be an available bifunctional electrocatalyst in DMFCs.
Fabrication of biobased heterogeneous solid Brønsted acid catalysts and their application on the synthesis of liquid biofuel 5-ethoxymethylfurfural from fructose
Yingying Wen, Zhou Yu, Kexin Li, Huiqin Guo, Yuhua Dai, Liushui Yan
2018, 3(4): 384-391. doi: 10.1016/j.gee.2018.07.003
Abstract HTML PDF
Abstract:
A series of biobased heterogeneous solid Brønsted acid catalysts with perfect spherical microstructures are successfully fabricated directly from waste Camellia oleifera shells by a simple hydrothermal carbonization-annealing-sulfonation process. 350 °C low temperature annealing process helps to increase the activity of the catalyst due to the simultaneous maintenance of the spherical microstructure and aromatic carbon framework. As a renewable catalyst with low cost, the as-prepared materials are successfully applied on the synthesis of green renewable liquid biofuel 5-ethoxymethylfurfural (EMF) directly from fructose. In the catalytic test, the influences of reaction time and temperature, fructose concentration, and adding amount of the catalyst on the yield of EMF are investigated systematically. As a result, the optimal reaction temperature is 100 °C, the EMF yield monotonically increases with prolonging the reaction time from 3 to 24 h, the optimal fructose concentration is 0.5 mmol, and the EMF yield gradually increases with increasing the adding amount of the catalyst from 50 to 150 mg. In addition, the as-prepared catalysts exhibit considerably high stability in the current EMF synthesis system, and they can maintain a similar level of reactivity after four catalytic cycles.

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