Making H₂ from Light and Biomass over Ni/Mo₂C Catalysts under Mild Conditions

Photothermal reforming of biomass to H₂ has emerged as a promising strategy for biomass utilization but remains an enormous challenge to construct an efficient conversion system under mild conductions. Here, Ni-coated Mo₂C microsphere (Ni/Mo₂C) composites with an electron-depletion Ni (Ni^δ+) region and an electron-accumulation Mo₂C (Mo₂C^δ-) region were developed as efficient catalysts for photothermal reforming of biomass to H₂ in neutral aqueous solution. In Ni/Mo₂C catalysts, the Ni^δ+ region acted as efficient Lewis acidic sites to be used as active sites for biomass oxidation, while Mo₂C^δ- can be used as active sites for the H₂ generation reaction, which enhances the photothermal catalytic activity of Ni/Mo₂C catalysts for biomass-to-H₂ conversion. As a result, common plant biomass was successfully converted to H₂ by Ni/Mo₂C catalysts in neutral aqueous solution with the maximum H₂ evolution rate of 117 μmol g^-1 h^-1 in the wheat straw system under 300 W Xe lamp irradiation.