金属修饰Ti_2N MXene吸附分解H_2S的第一性原理计算

通过第一性原理计算研究了Ti_2NO_2 MXene对H_2S的吸附、分解行为. Ti_2NO_2对H_2S气体分子的吸附结果表明,两者之间为弱的物理吸附, Ti_2NO_2无法有效吸附H_2S气体.采用过渡金属(Sc、 V)修饰Ti_2NO_2的研究结果表明,Sc和V可以在Ti_2NO_2表面上稳定存在,不易发生团聚,其最稳定吸附位为N原子上方.进一步研究了Sc、 V修饰的Ti_2NO_2对H_2S气体分子的吸附行为,结果表明金属修饰后其吸附H_2S的能力明显提高.此外还发现, H_2S分子可以在Sc/Ti_2NO_2和V/Ti_2NO_2表面直接解离为HS*和H*,而后HS*中的H原子再与H*进一步结合形成H_2, S原子则与过渡金属成键. HS*在V/Ti_2NO_2表面解离的势垒为1.69 eV,低于在Sc/Ti_2NO_2表面的2.08 eV,表明V/Ti_2NO_2有望成为吸附、分解H_2S气体的理想候选材料.

Adsorption and Decomposition of H2S on Metal-modified Ti2N MXene: A First Principle Calculation

First-principles calculations are used to study the adsorption and decomposition behavior of H2S on Ti2NO2 MXene. The adsorption results of H2S gas molecules by Ti2NO2 show that the adsorption belong to weak physical adsorption, and the H2S gas cannot be adsorbed effectively on Ti2NO2. The results of the modification of Ti2NO2 by transition metals (Sc, V) show that Sc and V can stably anchor on the surface of Ti2NO2 and are not easy to agglomerate, and the most stable adsorption site is the top of N atom. The adsorption behavior of H2S gas molecules on Sc and V modified Ti2NO2 are further studied. The results show that the adsorption strength of H2S was significantly improved on the transition-metal modified Ti2NO2. In addition, H2S molecules can be directly dissociated into HS* and H* on the surface of Sc/Ti2NO2 and V/Ti2NO2,?and then the H atom in HS* combines with H* to form H2, and the S atom bonds with the transition metal. The dissociation barrier of HS* on the surface of V/Ti2NO2 is 1.69 eV, which is lower than the 2.08 eV on the surface of Sc/Ti2NO2, indicating that V/Ti2NO2 is expected to be an ideal candidate material for H2S gas adsorption and decomposition.