Peng Kang, Zhou Jingxuan, Gao Hongfei, Wang Jianwei, Wang Hongjie, Su Lei, Wan Pengfei
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
ACS Appl Mater Interfaces. 2020 Apr 29;12(17):19519-19529. doi: 10.1021/acsami.0c02046. Epub 2020 Apr 15.
MoS has emerged as a good application prospect in the electrocatalytic hydrogen evolution reaction (HER). Nevertheless, the catalytic activity of MoS is greatly restricted by its inferior electrical conductivity, inadequate exposure of active edge sites, and sluggish water dissociation dynamics. Herein, a 1D/2D heteronanostructure composed of SiC nanowires wrapped with MoS nanosheets was prepared via the hydrothermal synthesis of MoS on highly connected SiC nanowires (SiCnw). The nanocomposites exhibit an emerging tectorum-like morphology with interface connections of C-Mo bonds, which benefit the efficient interfacial transmission of electrons. Due to the synergetic catalytic effects of MoS nanosheets and SiC nanowires, the MoS/SiCnw nanocomposites possess efficient catalytic performance with a low Tafel slope (55 mV/dec). SiC nanocrystals could reduce the activated water dissociation energy barrier, and the morphologies of connected nanowires could improve the active site exposure and charge transport. The nanocomposites possess favorable hydrogen adsorption free energy from density functional theory (DFT) calculations. The electrocatalytic performance of MoS/SiCnw nanocomposites could be further improved by assembling the nanocomposites on a carbon fiber paper to enhance the electronic transmission efficiency.
二硫化钼（MoS）在电催化析氢反应（HER）中展现出良好的应用前景。然而，MoS的催化活性受到其较差的导电性、活性边缘位点暴露不足以及缓慢的水离解动力学的极大限制。在此，通过在高度连通的碳化硅纳米线（SiCnw）上进行水热合成MoS，制备了一种由包裹着MoS纳米片的SiC纳米线组成的一维/二维异质纳米结构。该纳米复合材料呈现出一种新兴的类似屋顶的形态，具有C-Mo键的界面连接，这有利于电子的高效界面传输。由于MoS纳米片和SiC纳米线的协同催化作用，MoS/SiCnw纳米复合材料具有高效的催化性能，塔菲尔斜率低（55 mV/dec）。SiC纳米晶体可以降低活化水离解能垒，相连纳米线的形态可以改善活性位点暴露和电荷传输。通过密度泛函理论（DFT）计算，该纳米复合材料具有良好的氢吸附自由能。将该纳米复合材料组装在碳纤维纸上以提高电子传输效率，可进一步提升MoS/SiCnw纳米复合材料的电催化性能。
