Vanadium-doped molybdenum carbides as a promising catalyst for C–N/C–C coupling reactions†
Vanadium-doped molybdenum carbides (V-Mo2C) encapsulated in nitrogen-doped carbon have been prepared by annealing phosphovanadomolybdate (PMo10V2O405−)-paired ionic hybrids as the carbonization precursors. The V-Mo2C@NCt catalysts were pyrolyzed at various temperatures and characterized by XRD, BET, XPS, TEM, and Raman spectroscopy. The synthesized MoCV@NC800 showed a pomegranate-like structure with V-Mo2C nanocrystals well-dispersed in the NC shell. More importantly, MoCV@NC800 revealed extremely good catalytic activity and stability in the oxidative C–N coupling of amines to imines under mild conditions, which was much better than those of the monometallic carbide control catalysts. It was also observed that MoCV@NC800 exhibited high catalytic activity for the C–C bond couplings of alcohols and ketones. This work might provide a significant and interesting approach for designing more transition metal carbides as efficient organic synthesis heterogeneous catalysts.