One-step synthesis of armoured catalyst with ordered carbon layer coated FeCoNiCuZn high-entropy alloy for producing renewable hydrogen from biomass

One-step synthesis of an armoured catalyst featuring an ordered carbon layer-coated FeCoNiCuZn high-entropy alloy was reported for the catalytic reforming of biomass pyrolysis volatiles to produce renewable hydrogen. The prepared catalysts were characterized in detail by multiple techniques to reveal the features of the ordered carbon layer and the distribution of the high-entropy alloy. Response surface-centred combinatorial design (RSM-CCD) was employed to optimize the process conditions for hydrogen production from the catalytic pyrolysis of poplar wood sawdust. The results indicated that the FeCoNiCuZn-800 catalyst exhibited the best performance, and its unique structure contributed to an enhanced hydrogen yield. The enhanced catalytic performance stems primarily from the multi-element synergy within the HEA. Furthermore, the mesoporous structure facilitates mass transport, while the ordered carbon layers suppress nanoparticle agglomeration and promote electron transfer. The optimized process conditions were a pyrolysis temperature of 515 °C, a catalytic temperature of 622 °C, and a catalyst quality of 0.623 g. Under these conditions, the maximum hydrogen yield reached 40.10 vol% and 12.80 mmol·g⁻¹_biomass-daf, demonstrating the great potential of this catalyst in the field of renewable hydrogen production.