Biomass gasification reforming for hydrogen production by Ce-K co-catalysis coupled with CO₂ capture

Biomass gasification is a promising conversion pathway for renewable energy production, but it faces challenges such as low hydrogen yield. In this study, Ni-Ce-K/SiC catalysts were fabricated to enhance the gasification performance of pine sawdust for hydrogen production. The synergistic effect of Ce-K promoters on the catalytic performance and activity was investigated. In addition, CaO was applied as CO₂ capturing adsorbent during gasification reforming process. The results showed that optimization of Ce and K loadings in the presence of an in-situ CO₂ adsorbent significantly enhanced H₂ yield. The H₂ yield reached 36.31 mmol/g using the 10Ni4Ce1K/SiC catalyst at 500^oC, whereas it was only 5.28 mmol/g with 10NiCeK/SiC catalyst in the absence of CaO adsorbent. The 10Ni4Ce1K/SiC catalyst maintained the Ni⁰/NiO redox balance through the synergistic effect of the oxygen storage capacity of CeO₂ and the surface anchoring of K, leading to highest H₂ yield and carbon deposition primarily composed of highly defective disordered structures. The behavior of gasification reforming was also affected by the placement mode of catalyst and CaO adsorbent. Compared to direct physical mixing, the layered placement of catalyst and CaO can delay CaO sintering, H₂ yield in layered placement remained 82.9 % after 10 cycles.