Experimental investigation and analysis on oilseed rape straw pyrolysis with catalytic Fe/Ni-CaO for enhanced hydrogen production

With the depletion of fossil fuels and mounting carbon-reduction pressures, H 2 production via biomass pyrolysis has emerged as a promising sustainable energy route. A fluidized-bed system is employed for the pyrolysis of oilseed rape straw (ORS), utilizing efficient and low-cost catalysts to boost H 2 production. Effects of CaO-supported Ni-Fe bimetallic catalysts on enhancing H 2 yield and modifying char properties for ORS pyrolysis are experimentally conducted. The results demonstrate that the synergistic effects between Fe and Ni species supported on CaO promote the deep cracking of biomass-derived intermediates and steers the reaction pathways toward H 2 formation. Compared with non-catalytic ORS pyrolysis, the balanced Fe/Ni loading of 5%Fe-5%Ni/CaO catalyst enhances the gas yield. Furthermore, the ORS pyrolysis catalyzed by the 2%Fe-8%Ni/CaO catalyst achieves the highest hydrogen selectivity, increasing the H 2 volume fraction in the product gas from 24.1 vol% to 52.1 vol%. Additionally, char analysis indicates that the Ni-Fe bimetallic catalysts alter the elemental composition, surface functional groups, and pore structures of the pyrolytic char. Specifically, high-Ni-content catalysts facilitate the graphitization of char, while low-Fe-content catalysts enhance the defect density of the char structure. These findings highlight the potential of CaO-supported Ni-Fe bimetallic catalysts in optimizing biomass pyrolysis for the co-production of H 2 -rich gas and value-added char, thereby facilitating the development of carbon-neutral and resource-efficient energy systems. • Fe/Ni-CaO catalysts are synthesized and systematically characterized to enhance H 2 production. • The addition of Ni reduces the reduction temperature of the Fe catalysts, while Fe enhances the stability of Ni catalysts. • The 2%Fe-8%Ni/CaO catalytic ORS increased the H 2 fraction from 24.1 vol% to 52.1 vol%.