Pan Hui
Institute of Applied Physics and Materials Engineering, Faculty of Science and Technology, University of Macau, Macao SAR, China.
Nanoscale Res Lett. 2016 Dec;11(1):113. doi: 10.1186/s11671-016-1329-5. Epub 2016 Feb 29.
Water electrolysis is an efficient way for hydrogen production. Finding efficient, cheap, and eco-friendly electrocatalysts is essential to the development of this technology. In the work, we present a first-principles study on the effects of tension on the hydrogen evolution reaction of a novel electrocatalyst, vanadium disulfide (VS2) monolayer. Two electrocatalytic processes, individual and collective processes, are investigated. We show that the catalytic ability of VS2 monolayer at higher hydrogen coverage can be efficiently improved by escalating tension. We find that the individual process is easier to occur in a wide range of hydrogen coverage and the collective process is possible at a certain hydrogen coverage under the same tension. The best hydrogen evolution reaction with near-zero Gibbs free energy can be achieved by tuning tension. We further show that the change of catalytic activity with tension and hydrogen coverage is induced by the change of free carrier density around the Fermi level, that is, higher carrier density, better catalytic performance. It is expected that tension can be a simple way to improve the catalytic activity, leading to the design of novel electrocatalysts for efficient hydrogen production from water electrolysis.
水电解是一种高效的制氢方法。寻找高效、廉价且环保的电催化剂对该技术的发展至关重要。在这项工作中，我们对张力对新型电催化剂二硫化钒（VS2）单层析氢反应的影响进行了第一性原理研究。研究了两种电催化过程，即单个过程和集体过程。我们表明，通过增加张力可以有效提高VS2单层在较高氢覆盖度下的催化能力。我们发现，在较宽的氢覆盖度范围内单个过程更容易发生，而在相同张力下，在一定的氢覆盖度下集体过程是可能的。通过调节张力可以实现具有接近零吉布斯自由能的最佳析氢反应。我们进一步表明，催化活性随张力和氢覆盖度的变化是由费米能级附近自由载流子密度的变化引起的，即载流子密度越高，催化性能越好。预计张力可以成为提高催化活性的一种简单方法，从而设计出用于水电解高效制氢的新型电催化剂。
