Multistage construction of Gd-doped g-C3N4/Mo15S19 composites enabled both N2 activation and multiple electron transfer for an enhanced photocatalytic nitrogen reduction reaction

Abstract

The efficiency of photocatalytic nitrogen reduction reactions (NRRs) faces significant challenges due to the need for effective activation of the NN bond and efficient multi-electron/proton transfer. A novel Gd-doped and Mo₁₅S₁₉-loaded g-C₃N₄ nanorod (GdC₃N₄/Mo₁₅S₁₉) is promoted in this work. The experimental results show that the GdC₃N₄/Mo₁₅S₁₉ composite exhibits remarkable visible-light-driven photocatalytic ammonia production (407.51 μmol g⁻¹ h⁻¹, 33 times that of g-C₃N₄), which is attributed to the promoted multiple electron transfer by in-built Gd³⁺ redox centers and increased Mo active sites by loading of Mo₁₅S₁₉. Calculations using Density Functional Theory (DFT) show that Mo₁₅S₁₉ loading also helps to effectively activate the NN bond, which accelerates the NRR's start. The synergistic effect of Gd doping and Mo₁₅S₁₉ loading lowers the Gibbs free energy of intermediates, enhancing the overall photocatalytic efficiency. This work provides a viable approach to the construction of multistage structures in the photocatalytic NRR that incorporates multiple electron transfer and N₂ activation effects.