Two-Dimensional WO3-Transition-Metal Dichalcogenide Vertical Heterostructures for Nitrogen Fixation: A Photo(Electro) Catalysis Theoretical Strategy

Nitrogen fixation is one of the most critical issues in chemical science and technology. However, the exploitation of efficient and stable photo(electro) catalysts remains a full challenge. Herein, we systematically investigate the general strategy for constructing a novel vertical heterostructure constructed using two-dimensional (2D) WO3 in contact with transition-metal dichalcogenides (TMDCs), including MoS2, MoSe2, WS2, and WSe2, and all heterostructures are theoretically used as efficient photo(electro) catalysts for the nitrogen reduction reaction (NRR). As expected, all the heterostructures are thermodynamically stable by computational results. Notably, the photocatalytic mechanism is elucidated based on time-dependent ab initio nonadiabatic molecular dynamics simulations. The N2 molecules can be efficiently reduced into NH3 through a distal mechanism with onset potentials lower than 0.50 V in the four counterparts. In particular, the optimized WO3-MoS2 possesses the lowest onset potential (0.25 V) with respect to free energy. The catalytic activity can be enhanced by repositioning the d-band center, accurately controlled by the TMDC, to a higher energy level. The synergistic effect of the two components and the regulation of the d-band are critical factors to improve the heterostructure catalytic efficiency. Foreseeably, these findings provide a new avenue for developing cost-effective alternatives for nitrogen fixation.