Catalytic pyrolysis of biomass to aromatics over bifunctional Ni/ZSM-5 catalysts assembled on rice husk-derived silica platform

Summary

Biomass resources can be converted to biochemicals via the catalytic pyrolysis process, but conventional catalysts often suffer from severe deactivation due to coke formation. Here, a ternary Ni/bio-Z5 catalyst was constructed by integrating ZSM-5 and Ni components on a porous bio-SiO₂ platform derived from rice husk. The Ni/bio-Z5 achieved 76% aromatic selectivity for the catalytic pyrolysis of soybean oil, corresponding to a space-time yield as high as 154.8 g_arom · h⁻¹ · g_cata⁻¹. It is confirmed that the bio-SiO₂ platform shortened the surface diffusion path of aromatics by co-diffusion, which then inhibited coke formation and significantly improved the catalyst stability. Moreover, the atomically dispersed Ni on ZSM-5 effectively promotes the aromatization of C₂⁼-C₆⁼ by enhancing adsorption and acting as an oligomerization center for isoalkyl carbenium ions. The coupling of deoxygenation and aromatization reactions promotes the enhancement of aromatic selectivity through the formation of methyl-substituted cyclopentenone that can be readily converted to aromatics.