Pham Kien-Cuong, Chang Yung-Huang, McPhail David S, Mattevi Cecilia, Wee Andrew T S, Chua Daniel H C
NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore , 28 Medical Drive, Singapore 117456, Singapore.
Department of Materials, Imperial College London , Exhibition Road, London, SW7 2AZ, United Kingdom.
ACS Appl Mater Interfaces. 2016 Mar 9;8(9):5961-71. doi: 10.1021/acsami.5b09690. Epub 2016 Feb 24.
In this study, we report on the deposition of amorphous molybdenum sulfide (MoSx, with x ≈ 3) on a high specific surface area conductive support of Graphene-Carbon Nanotube hybrids (GCNT) as the Hydrogen Evolution Reaction (HER) catalysts. We found that the high surface area GCNT electrode could support the deposition of MoSx at much higher loadings compared with simple porous carbon paper or flat graphite paper. The morphological study showed that MoSx was successfully deposited on and was in good contact with the GCNT support. Other physical characterization techniques suggested the amorphous nature of the deposited MoSx. With a typical catalyst loading of 3 mg cm(-2), an overpotential of 141 mV was required to obtain a current density of 10 mA cm(-2). A Tafel slope of 41 mV decade(-1) was demonstrated. Both measures placed the MoSx-deposited GCNT electrode among the best performing molybdenum sulfide-based HER catalysts reported to date. The electrode showed a good stability with only a 25 mV increase in overpotential required for a current density of 10 mA cm(-2), after undergoing 500 potential sweeps with vigorous bubbling present. The current density obtained at -0.5 V vs SHE (Standard Hydrogen Electrode potential) decreased less than 10% after the stability test. The deposition of MoSx on high specific surface area conductive electrodes demonstrated to be an efficient method to maximize the catalytic performance toward HER.
在本研究中，我们报道了非晶态硫化钼（MoSx，x≈3）沉积在石墨烯 - 碳纳米管杂化物（GCNT）的高比表面积导电载体上作为析氢反应（HER）催化剂的情况。我们发现，与简单的多孔碳纸或平面石墨纸相比，高表面积的GCNT电极能够支持以更高的负载量沉积MoSx。形态学研究表明，MoSx成功沉积在GCNT载体上并与其良好接触。其他物理表征技术表明所沉积的MoSx具有非晶态性质。在典型的催化剂负载量为3 mg cm(-2)时，要获得10 mA cm(-2)的电流密度需要141 mV的过电位。测得的塔菲尔斜率为41 mV dec(-1)。这两项指标都表明，沉积了MoSx的GCNT电极是迄今为止报道的性能最佳的基于硫化钼的HER催化剂之一。该电极表现出良好的稳定性，在有剧烈气泡存在的情况下进行500次电位扫描后，对于10 mA cm(-2)的电流密度，过电位仅增加25 mV。在稳定性测试后，相对于标准氢电极（SHE）在 -0.5 V时获得的电流密度下降不到10%。在高比表面积导电电极上沉积MoSx被证明是一种最大化析氢反应催化性能的有效方法。
