Surface reconstruction and the effect of Ni-modification on the selective hydrogenation of 1,3-butadiene over Mo2C-based catalysts

Abstract

In the current study, Mo₂C, NiMo₂C, H–Mo₂C and H–NiMo₂C were synthesized to understand the effects of Ni modification and synthesis routes. The catalysts were characterized by XRD, N₂-physisorption, SEM, TEM, XPS and pulse CO chemisorption and were evaluated in a fixed-bed reactor. The catalysts are found to undergo surface reconstruction during the reaction–regeneration process and thereafter exhibit better stability. Among the investigated catalysts, H–NiMo₂C exhibits the best stability and H–Mo₂C exhibits the highest butene selectivity. The electronic effect induced by Ni-modification via the conventional route could enhance the butene selectivity. The high butene selectivity over the unmodified H–Mo₂C via the HA-TPC route may stem from surface vacancies and the presence of α-Mo_1−xC. This work for the first time reports the 1,3-butadiene hydrogenation over Mo₂C-based catalysts under steady state conditions; the surface reconstruction and the effect of Ni-modification will inspire us to develop industrial non-noble metal catalysts.