过渡金属掺杂氮基MXenes用于析氢反应的研究

Transition metal doped nitrogen-based MXenes for enhanced hydrogen evolution reaction

二维过渡金属碳化物和氮化物(MXenes)因其高比表面积、优异的热稳定性和高电导率而成为有前途的析氢反应(HER)催化剂。然而,只有少数MXenes材料在HER中显示出催化活性。本研究利用密度泛函理论(DFT)计算研究了过渡金属(LM)掺杂M_(2)NO_(2)型MXenes对其氢吸附吉布斯自由能(ΔG_(H)^(*))的影响及对HER催化活性的增强作用。结果表明,Zr_(2)NO_(2)和Ta_(2)NO_(2)具有成为HER活性催化剂的潜力。与未掺杂M_(2)NO_(2)相对较弱的HER活性相比,掺杂LM原子后MXenes的HER催化活性被有效提高。通过对MXenes的电子结构及其与氢原子相互作用的研究可知,不同LM原子的掺杂是通过改变O原子的Bader电荷分布,从而影响O-H键的强度,进而改善MXenes在HER中的催化性能。

Two-dimensional metal carbide and nitride(MXenes)based materials have emerged as promising hydrogen evolution reaction(HER)catalysts due to their high surface area,excellent thermostability,and high electronic conductivity.However,only a few pristine MXenes materials showed catalytic activity in HER.In this work,we studied the enhancement effect of HER activity of transition metal(LM)substituted M_(2)NO_(2)type MXenesbyutilizing density functional theory(DFT)calculations on their relative Gibbs free energies of H-adsorption(ΔG_(H)^(*)).Based on theresults,Zr_(2)NO_(2)and Ta_(2)NO_(2)have the potential to be HER active catalysts.Compared to the relatively weak HER activity of pristine M_(2)NO_(2),the replacement of LM atoms in MXenes can effectively improve the HER activity.Based on the study of the electronic structure and interaction between hydrogen atom and MXenes,the substitution of different LM atoms can change the Bader charge of O atom,thus affecting the strength of O-H bond.