Glycerol Steam Reforming for Hydrogen over Mo-Modified Attapulgite-Based Zeolite-Supported Ni-Based Catalysts

Obtaining green hydrogen from glycerol steam reforming (GSR) is a promising approach for the efficient utilization of crude glycerol derived from the biodiesel market, while it faces significant challenges. Herein, Mo-modified attapulgite-based zeolite (AZc)-supported Ni-based catalysts (named as NixMo/AZc) were prepared for GSR. It demonstrated that AZc could reduce the proportion of strong acid sites and promote the reduction of nickel species; meanwhile, the Mo additive yielded an intermetallic interaction between nickel and molybdenum to facilitate the formation of Ni–Mo alloy phases and abundant oxygen vacancies (O V ). These characteristics effectively inhibited the dehydration of glycerol, the sintering of active Ni metals, and the formation of carbon deposits during GSR process. Among them, Ni3Mo/AZc achieved the highest glycerol conversion (95.3%) and hydrogen yield (77.3%) and maintained the superior catalytic stability during 50 h of GSR at 600 °C. Additionally, the reaction pathway investigation exhibited that Ni3Mo/AZc promoted the dehydrogenation of glycerol and the acetol intermediate and the breakage of C–C bonds; then, its metallic Ni and Ni–Mo alloy sites coupled with O V enhanced the water–gas shift reaction and the steam reforming of various intermediates to yield more hydrogen. This study provides a feasible strategy for the high-value utilization of glycerol through steam reforming along with the efficient production of green hydrogen.