材料科学
塔菲尔方程
化学工程
碳化钨
电催化剂
催化作用
碳纤维
电解
纳米技术
阴极
纳米晶
电化学
电极
复合材料
复合数
有机化学
电解质
化学
物理化学
工程类
作者
Qi Feng,Yongyueheng Xiong,Linjing Xie,Zhen Zhang,Xiner Lu,Yajun Wang,Xiao‐Zi Yuan,Jiantao Fan,Haijiang Wang
标识
DOI:10.1021/acsami.9b04725
摘要
Tungsten carbide (WC) is an alternative to the costly and resource-constrained Pt-based catalysts. Herein, a one-step facile and easily scalable approach is reported to synthesize ultrafine WC nanocrystals encapsulated in porous N-doped carbon nanospheres (NC) by simple self-polymerization, drying, and annealing. It is worth mentioning that this developed method has four novel features: (1) the synthesis process, without any hard template or hydrocarbon gas feeding, is, notably, very facile and efficient with low cost; (2) the carbon coating on WC nanocrystals not only restrains coarsening of particles but also creates strong coupling interactions between the nanocrystallines and the conductive carbonaceous matrix; (3) uniform grape-like WC@NC nanospheres with high specific surface area can be obtained in a large scale; and (4) single-phase WC can be achieved. As a result, WC@NC demonstrates remarkable hydrogen evolution reaction (HER) electrocatalytic performance with overpotentials of 127 and 141 mV at a current density of 10 mA cm-2 and Tafel slopes of 56.3 and 78.7 mV dec-1 in acid and alkaline media, respectively. Our density functional theory calculations manifest that the strong synergistic electronic effect between WC and its intimately bonded carbon shell vastly boosts the HER electrocatalytic activity. WC@NC catalysts as a cathode are further tested in a home-made electrolyzer with 0.78 A cm-2 achieved at a cell voltage of 2 V at 80 °C and operated stably at 200 mA cm-2 for more than 20 h.
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