High hydrogen production from raw biomass via crystal phase regulation of Al2O3 supported Ni catalyst

Naturally abundant biomass exhibited a complex structure with diversified chemical bonds, it brought about great challenges for the directly high-efficiency conversion of raw biomass into hydrogen under mild conditions. Here, it developed an efficient approach to catalyze cleavage of O-H, C-H and C-C bonds with the sequential water gas shift in lignocellulosic biomass through the enhanced catalytic performance of Ni-supported catalysts with the crystal phase regulation of Al2O3. The introduction of Ba(OH)2 greatly enhanced the production of hydrogen over Ni/γ-Al2O3, and H2 production of 69.9 mmol gwood‐1 was acquired from the directly catalytic conversion of raw biomass. Further reaction pathway investigation revealed that more basic sites in Ni/γ-Al2O3 were beneficial to the cleavage of O-H bonds and form the adsorbed ethoxide, which facilitated the further cleavage of α-C-H bonds. Meanwhile, the hydrogen spillover in Ni/γ-Al2O3 could promote the H2 generation, and it also provided more NiAl2O4 species to break the C-C bonds and form Nix (CO)y species, which accelerated the water gas shift to produce hydrogen. Our strategy provides guidance in the catalytic production of sustainable hydrogen as well as the low carbon future.