Wang Junmei, Tian Qingkun, Chen Li, Yang Maoyou, Zhang Xia, Wang Xiaodan
International School for Optoelectronic Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China.
ACS Omega. 2024 Dec 9;9(50):49945-49952. doi: 10.1021/acsomega.4c09193. eCollection 2024 Dec 17.
The development of catalysts with high activity and selectivity for the electrochemical nitrogen reduction reaction (NRR) remains crucial. Molybdenum carbide (MoC) shows promise as an electrocatalyst for NRR but faces challenges due to the difficulty of N adsorption and activation as well as the competitive hydrogen evolution reaction. In this study, we propose a strategy of combining TiO with MoC to form heterostructure catalysts. Our first-principles theoretical calculations indicate that the TiO-MoC heterostructure exhibits enhanced N adsorption and activation, attributed to the increased interaction between the π orbital of Mo and the π orbital of N, facilitated by the directional modulation of Mo's d-orbitals by TiO. A more positive integrated crystal orbital Hamilton population and an elongated N≡N bond length prove this. Additionally, the higher Gibbs free energy for N compared to that for H demonstrates a preference for N adsorption. We further elucidate the catalytic mechanism for converting N to NH on the TiO-MoC surface, identifying the associative distal pathway as the dominant route over the associative alternating pathway. This work highlights unique advantages of the TiO-MoC heterostructure for the NRR and provides theoretical guidance for designing efficient NRR electrocatalysts.
开发具有高活性和选择性的电化学氮还原反应（NRR）催化剂仍然至关重要。碳化钼（MoC）作为NRR的电催化剂显示出潜力，但由于氮吸附和活化困难以及存在竞争性析氢反应而面临挑战。在本研究中，我们提出了一种将TiO与MoC结合形成异质结构催化剂的策略。我们的第一性原理理论计算表明，TiO-MoC异质结构表现出增强的氮吸附和活化，这归因于Mo的π轨道与N的π轨道之间相互作用的增加，这是由TiO对Mo的d轨道的定向调制所促进的。更正值的积分晶体轨道哈密顿布居和拉长的N≡N键长证明了这一点。此外，与H相比，N的吉布斯自由能更高，表明更倾向于氮吸附。我们进一步阐明了TiO-MoC表面上N转化为NH的催化机制，确定缔合远端途径是优于缔合交替途径的主要途径。这项工作突出了TiO-MoC异质结构在NRR方面的独特优势，并为设计高效的NRR电催化剂提供了理论指导。
