Enhanced hydrogen production from acetate-impregnated bagasse catalytic pyrolysis: Unraveling the superiority of nickel over alkali metals

This study investigates the catalytic pyrolysis of bagasse, a major agricultural waste, for high-yield hydrogen production using metal acetates (Ni, K, Na). An incipient wetness impregnation method was employed to synthesize metal-loaded bagasse, with nickel demonstrating superior catalytic performance. At an optimal loading of 5 wt% Ni, a maximum hydrogen yield of 87.8 mmol/g was achieved at 800 °C, significantly higher than yields from Na and K. The formation of highly dispersed Ni species was evidenced by XRD and SEM-Mapping. FTIR revealed Ni species facilitate selective cleavage of C–H and O–H bonds, and Raman verified Ni promotes ordered carbon rearrangement, favoring highly graphitized carbon. TPO-MS demonstrated the improved hydrogen evolution behavior in the presence of Ni. Soft X-ray absorption spectroscopy at the C K -edge and Ni L -edge further revealed that the highly dispersed Ni species anchored on graphitic carbon matrices served as active sites for hydrogen evolution. The Ni-modified catalyst also significantly improved hydrogen yield during the pyrolysis of other tropical agricultural residues (durian shell and coconut shell), demonstrating broad applicability. The findings establish a sustainable and efficient strategy for hydrogen-rich syngas production from biomass, highlighting the potential of nickel-acetate in enabling low-carbon energy from widespread agro-industrial wastes.