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Yuanshuang Wang, Junxiang Chen, Genxiang Wang, Yan Li, Zhenhai Wen
Developing cost-effective electrocatalysts for high-selectivity CO2 electroreduction remains a daunting challenge. We here report a perfluroinated covalent triazine framework (CTF) electrocatalyst that holds an impressive high selectivity towards CO2 electroreduction conversion into CH4 with faradaic efficiency of 99.3% in aqueous electrolyte. Systematic characterization and electrochemical study, coupling with density functional theory calculations, demonstrate that co-covalent of nitrogen and fluorine in CTF provides a unique pathway that is inaccessible with the individual components for CO2 electroreduction, contributing to the catalytic sites with high selectivity for CO2 conversion into CH4...
August 14, 2018: Angewandte Chemie
Lu Chen, Huijuan Huang, Yuanhui Zheng, Wenhao Sun, Yi Zhao, Paul S Francis, Xuxu Wang
The majority of visible-light photocatalysts show very low hydrogen evolution activity in the absence of noble metal co-catalysts due to their fast carrier recombination rate. Metallic interstitial nitrides have been recognized as excellent hydrogen evolution electrocatalysts and therefore are promising alternative co-catalysts for photocatalytic hydrogen production. Herein we report a low-cost, efficient, noble-metal-free visible-light-driven hydrogen evolution photocatalyst composed of Ni3N/g-C3N4 heterostructures...
August 14, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Shuai Wang, Gyutae Nam, Ping Li, Haeseong Jang, Jia Wang, Min Gyu Kim, Zexing Wu, Xien Liu, Jaephil Cho
Developing highly efficient non-noble metal electrocatalysts for oxygen electrode reactions is highly desirable for industrial scale application in energy related devices. Herein, two new kinds of Ni (POxN3-x)2/NPC and Co (POxN3-x)2/NPC (NPC: N, P-co-doped carbon) are synthesized through a facile post-treatment of nickel- or cobalt-phytic acid xerogel, followed by an annealing procedure under an argon and ammonia atmosphere at 800 °C. The as-prepared catalysts exhibit outstanding catalytic activities for both the oxygen reduction and evolution reactions, which are comparable to those of Pt/C and IrO2...
August 14, 2018: Nanoscale
Javad Tashkhourian, Hamed Valizadeh, Abdolkarim Abbaspour
Background: Metal-organic frameworks (MOFs) are classified as microporous materials. They have large surface areas, low framework densities, accessible cages, and tunnels with modifiable pores. Objective: The MOF MIL-101(Cr) with a large pore volume was synthesized hydrothermally and used in the electrochemical reactions as an electrocatalyst for the determination of ascorbic acid (AA). The synthesized MOF was characterized by scanning electron microscopy and X-ray powder diffraction. Methods: The electrocatalytic behavior of a carbon-paste electrode modified with MIL-101(Cr) was studied through electro-oxidation of AA by cyclic voltammetry and square wave voltammetry...
August 13, 2018: Journal of AOAC International
Xueting Feng, Qingze Jiao, Huiru Cui, Mengmeng Yin, Qun Li, Yun Zhao, Hansheng Li, Wei Zhou, Caihong Feng
The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are considered to be cornerstones of many energy conversion and storage technologies. It is difficult study high-performance non-precious materials as cost-effective bifunctional electrocatalysts for both the OER and ORR in future practical applications. In this study, NiCo2S4 hollow spheres (NiCo2S4 HSs) were fabricated via an effective and facile one-pot "green" approach in an N,N-dimethylformamide (DMF) - ethylene glycol (EG) binary solution...
August 13, 2018: ACS Applied Materials & Interfaces
Alaaldin Adam, Munzir H Suliman, Mohammad N Siddiqui, Zain H Yamani, Belabbes Merzougui, Mohammad Qamar
Transition metal phosphides are deemed as potential alternative to platinum for large scale and sustainable electrocatalytic hydrogen production from water. In this study, facile preparation of interconnected hollow cobalt monophosphide (CoP) supported on carbon nanotubes is demonstrated, and evaluated as a low-cost electrocatalyst for hydrogen evolution reaction (HER). Hexamethylenetetramine is used as a structure-directing agent to guide the formation of interconnected cobalt oxide, which further grows into interconnected hollow CoP...
August 13, 2018: ACS Applied Materials & Interfaces
Qiyu Wang, Zhian Zhang, Mengran Wang, Fangyang Liu, Liangxing Jiang, Bo Hong, Jie Li, Yanqing Lai
Laccase is one of the most effective biocatalysts for oxygen reduction under physiological conditions. Its unique Cu- and N-based active sites with direct electrical pathways for electrons can guarantee rapid oxygen exchange and reduction. Inspired by this specific structure, we designed and fabricated porous fiber-like Cu/N/C based on MOFs as an ORR catalyst. Precision morphology control of fibers contributed to an increase in the electron transport rate compared with that of Cu/N/C nanoparticles, which could minimize interparticle ohmic contacts and provide direct electrical pathways along with sufficient active sites to catalyze oxygen reduction...
August 13, 2018: Nanoscale
Zhen Zhang, Ping Li, Qi Feng, Bing Wei, Chenglong Deng, Jiantao Fan, Hui Li, Haijiang Wang
Designing highly active, stable and cost-efficient electrocatalysts as alternatives to replace Pt is extremely desirable for the hydrogen evolution reaction (HER). Despite much progress that has been made based on complete non-precious metals (NPM), very few NPM catalysts have showed comparable performance to Pt-based catalysts. Herein, a cost-efficient, environmentally-friendly and scalable method to synthesize novel ruthenium(Ru)-doped transition metal carbide (Mo2C) hybrid catalyst was proposed. The hybrid nanoparticles were uniformly distributed and strongly embedded in biomass-derived highly porous N-doped carbon framework...
August 13, 2018: ACS Applied Materials & Interfaces
Yu Hang Li, Peng Fei Liu, Chunzhong Li, Huagui Yang
Electrochemical carbon dioxide reduction is a key reaction for carbon dioxide conversion to valuable fuels and chemicals. Because of the intrinsic stability of carbon dioxide molecule, a catalyst is thus required to minimize the energy input and improve reaction rates. Although the developed catalysts still suffer from low catalytic activity, selectivity, and stability, these could be enhanced by the involvement of sharp-tip structure. Here, we report a nanowire-like zinc electrocatalyst with sharp tips for carbon dioxide reduction...
August 13, 2018: Chemistry: a European Journal
Kexin Zhang, Chong Qu, Zibin Liang, Song Gao, Hao Zhang, Bingjun Zhu, Wei Meng, Engang Fu, Ruqiang Zou
Oxygen reduction and evolution reactions as two important electrochemical energy conversion processes in metal-air batteries devices have aroused widespread concern. However, synthesis of low-cost non-noble metal-based bifunctional high performance electrocatalysts is still a great challenge. In this work, we report on the design and synthesis of a novel Co-B/N co-doped carbon with core-shell-structured nanoparticles aligned on graphene nanosheets (denoted as CoTIB-C/G) derived from cobalt tetrakis(1-imidazolyl)borate (CoTIB) and graphene oxide hybrid template...
August 13, 2018: ACS Applied Materials & Interfaces
Zuozhong Liang, Xing Fan, Haitao Lei, Jing Qi, Youyong Li, Jinpeng Gao, Meiling Huo, Haitao Yuan, Wei Zhang, Haiping Lin, Haoquan Zheng, Rui Cao
Oxygen reduction reaction (ORR) is a critical issue and of significant importance in the development of fuel cells. Herein, cobalt-nitrogen-doped chiral carbonaceous nanotubes (L/D-CCNTs-Co) have been reported as efficient electrocatalysts for ORR. The chiral template, N-stearyl-L/D-glutamic acid, induces the self-assembly of well-arranged polypyrrole and the formation of ordered graphene carbon with helical structures at the molecular level after the pyrolysis process. Co has subsequently been introduced through the post-synthesis method...
August 10, 2018: Angewandte Chemie
Zhigang Geng, Yan Liu, Xiangdong Kong, Pai Li, Kan Li, Zhongyu Liu, Junjie Du, Miao Shu, Rui Si, Jie Zeng
The electrochemical reduction of N2 into NH3 production under ambient conditions represents an attractive prospect for the fixation of N2 . However, this process suffers from low yield rate of NH3 over reported electrocatalysts. In this work, a record-high activity for N2 electrochemical reduction over Ru single atoms distributed on nitrogen-doped carbon (Ru SAs/N-C) is reported. At -0.2 V versus reversible hydrogen electrode, Ru SAs/N-C achieves a Faradaic efficiency of 29.6% for NH3 production with partial current density of -0...
August 10, 2018: Advanced Materials
Weijia Han, Karsten Küpper, Peilong Hou, Wajiha Akram, Henning Eickmeier, Jörg Hardege, Martin Steinhart, Helmut Schäfer
A novel oxygen evolution reaction (OER) catalyst (3D S235-P steel) based on steel S235 substrate has been successfully prepared via a facile one-step surface modification. The standard Carbon Manganese steel was phosphorizated superficially leading to the formation of a unique 3D interconnected nanoporous surface with high specific area which facilitates the electrocatalytically initiated oxygen evolution reaction. The prepared 3D S235-P steel exhibits enhanced electrocatalytic OER activities in alkaline regime confirmed by a low overpotential (η=326 mV at j=10 mA cm-2) and a small Tafel slope of 68...
August 10, 2018: ChemSusChem
Dong Young Chung, Ji Mun Yoo, Subin Park, Gwan Yeong Jung, Jin Soo Kang, Chi-Yeong Ahn, Sang Kyu Kwak, Yung-Eun Sung
Transition metal dichalcogenides, especially MoS2 , are considered as promising electrocatalysts for hydrogen evolution reaction (HER). Since the physicochemical properties of MoS2 and electrode morphology are highly sensitive factor for HER performance, designed synthesis is highly pursued. Here, an in situ method to prepare a 3D carbon/MoS2 hybrid catalyst, motivated by the graphene ribbon synthesis process, is reported. By rational design strategies, the hybrid electrocatalysts with cross-connected porous structure are obtained, and they show a high HER activity even comparable to the state-of-the-art MoS2 catalyst without appreciable activity loss in long-term operations...
August 10, 2018: Small
Yuyin Wang, Mingming Zhao, Qunxing Zhao, Qing Li, Huan Pang
The development of inexpensive, highly active, bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is required for many energy conversion systems, including water splitting, fuel cells, and metal-air batteries. This study reports silver nanowires-zeolitic imidazolate framework (Ag NWs-ZIF67) composites as bifunctional electrocatalysts for OER and ORR. The synergistic effects of Co2+, organic ligands, and Ag NWs enhance the bifunctional electrocatalytic properties...
August 10, 2018: Nanoscale
Yukun Xiao, Zhihua Cheng, Yang Zhao, Liangti Qu
The rational design of an efficient and robust oxygen reduction reaction (ORR) electrocatalyst is vital for energy conversion and storage systems, especially for metal-air batteries. Herein, we report a highly nanocrumpled and nitrogen, phosphorus-codoped nanocarbon (NC-NPC) synthesized by direct pyrolysis of melamine and triphenylphosphine. With the rich nano-crumpled structure and codoping of heteroatoms, this low-cost catalyst exhibits an excellent ORR performance, and possesses a half-wave potential of 0...
August 9, 2018: Nanoscale
Xiaoqiang Du, Nai Li, Xiaoshuang Zhang
Exploitation of environmentally friendly electrocatalysts for a robust oxygen evolution reaction (OER) in an alkaline medium is very satisfactory. Here, a very low cell voltage of 1.65 V is acquired when Co3O4@NiMoO4/NF is firstly used as a bifunctional water splitting catalyst with 10 mA cm-2 in 1.0 M KOH.
August 9, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Jing-Fang Huang, Po-Kai Tseng
Bimetallic Pt-Ni with Pt on the outermost layer and an innermost layer enriched in Ni, referred to as Pt3 Ni(Pt-skin), is a promising configuration of an electrocatalyst for the oxygen reduction reaction (ORR) in fuel cells. We prepare a core (Pd)/shell (Pt3 Ni(Pt-skin)) catalyst (Pt3 Ni(Pt-skin)/Pd/C) from Zn underpotential deposition (UPD) on a Ni UPD modified Pd/C catalyst, facilitating Pt atomic layer-by-layer growth on the Ni surface through the galvanic replacement process. Pt3 Ni(Pt-skin)/Pd/C shows the best ORR performance, with a Pt specific activity of 16...
July 28, 2018: Chemical Science
Qichen Wang, Yongpeng Lei, Yinggang Zhu, Hong Wang, Junzong Feng, Guangying Ma, Yingde Wang, Youji Li, Bo Nan, Qingguo Feng, Zhouguang Lu, Hao Yu
Metal-free bifunctional oxygen electrocatalysts are extremely critical to the advanced energy conversion devices, such as high energy metal-air batteries. Effective tuning of edge defects and electronic density on carbon materials via simple methods is especially attractive. In this work, a facile alkali activation method has been proposed to prepare carbon with large specific surface area and optimized porosity. And subsequent nitrogen-doping leads to high pyridinic-N & graphitic-N content and abundant edge defects, further enhancing electrochemical activities...
August 8, 2018: ACS Applied Materials & Interfaces
Shuguang Wang, Xixi Ji, Yu Ao, Jie Yu
Diamond/graphite hybrid nanosheets (DGNSs) have been epitaxially grown on boron-doped diamond (BDD) films from CH4/H2 mixture gas by microwave plasma chemical vapor deposition. The DGNSs are vertically aligned on the crystal facets of the BDD films uniformly, densely, and orderly. The DGNSs are composed of the core diamond sheets and the surface graphitic overlayers, which possess an open edge structure. By post-treatment in NH3 atmosphere in microwave plasma or tube furnace the N-doped DGNSs (NDGNSs) were obtained...
August 7, 2018: ACS Applied Materials & Interfaces
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