Gan Jinyu, Li Fuhua, Tang Qing
School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China.
J Phys Chem Lett. 2021 May 27;12(20):4805-4813. doi: 10.1021/acs.jpclett.1c00917. Epub 2021 May 17.
Vacancy engineering is proposed to effectively modulate the hydrogen evolution reaction (HER) activity of MCO MXene. A single C vacancy slightly weakens the H adsorption, while the introduction of a M vacancy or coupled M+C vacancies can greatly enhance the H binding. For a MXene with intrinsic too-strong H adsorption, double C vacancies are effective in weakening the binding and promoting the activity. The activity tuning is closely correlated to the electronic structures of the defected MXene, where the highest occupied peak position of the surface O electronic states shows an apparent linear trend with Δ and can be used to qualitatively predict the activity. The weakened or strengthened H adsorption by a C or M vacancy is attributed to the upshifted or downshifted Fermi level of surface O, respectively. Our results indicate the potential of defect chemistry to tune the catalytic activity of MXene and provide new possibilities to enhance the applications of MXene.
提出空位工程以有效调节MCO MXene的析氢反应（HER）活性。单个C空位会略微削弱H吸附，而引入M空位或耦合的M + C空位则可大大增强H结合。对于本征H吸附过强的MXene，双C空位可有效减弱结合并促进活性。活性调谐与缺陷MXene的电子结构密切相关，其中表面O电子态的最高占据峰位置与Δ呈现明显的线性趋势，可用于定性预测活性。C或M空位对H吸附的减弱或增强分别归因于表面O的费米能级上移或下移。我们的结果表明缺陷化学在调节MXene催化活性方面的潜力，并为增强MXene的应用提供了新的可能性。
