Sustainable Photothermal Reforming of Biomass to H₂ over MoO₂ Catalysts under Mild Conditions

Solar-driven photothermal catalytic conversion of renewable biomass to chemical fuels plays an important role in promoting the realization of a carbon-neutral society, but the development of an effective conversion system under mild conditions remains an enormous challenge. Herein, oxygen vacancy-rich MoO₂ grown on graphite carbon (MoO₂@GC) was designed as an efficient photothermal catalyst to achieve biomass-to-H₂ conversion under mild conditions in a neutral solution. Under 300 W Xe lamp irradiation, the optimized MoO₂@GC catalyst achieves rapid H₂ generation from an α-cellulose aqueous solution with a H₂ generation rate of 29 μmol·h^-1·g^-1. Meanwhile, common biomass types including rape straw, rice hull, corn straw, bamboo, wheat straw, wood chip, rice straw, corn cob, and soybean straw were successfully converted to H₂ by the MoO₂@GC catalyst with the maximum H₂ evolution rate of 22 μmol·h^-1·g^-1 in a wheat straw system. Experimental and theoretical calculations reveal that the successful photothermal catalytic conversion of biomass to H₂ by MoO₂@GC under neutral condition is related to the existence of oxygen vacancy, which induces the formation of coordination unsaturated Mo ions and thus provides efficient active sites for biomass oxidation. This study opens a new opportunity for realizing H₂ production from biomass under mild condition in a neutral solution.