Atomic scale niobium implantation in a dealuminated industrial H-β zeolite catalyst for enhanced furfural production

Abstract

To develop an industrial zeolite-based catalyst for efficient furfural production, the acidity, pore structure, and electronic properties of H-β zeolite were modulated via synergistic deatomization and atomic implantation treatments. The dealumination effectively decreased the intrinsic aluminum-related Lewis and Brønsted acid sites, thus decreasing the occurrence of unwanted side reactions. The aluminum removed from the skeleton can create voids for the subsequent atomic implantation of higher valent-state niobium species, which could provide new kinds of catalytic active sites, increase the average pore size by distorting the zeolite skeleton, and enhance the interaction with reactant molecules by acting as more electron-deficient centers. In a single-phase water/γ-valerolactone reaction system, an optimum catalyst can efficiently convert both xylan and xylose with a conversion of 100% at a medium temperature of 130 °C within 3 hours. Compared with the furfural yield over untreated H-β (12.7%), the yield over the deAlβ/Nb(20%) catalyst was greatly enhanced by 54% with xylose as the raw material. The catalyst can be recovered via simple cleaning and thermal regeneration and then be reused. The proposed post-treatment strategy could maintain the integrity of the zeolite structure, ensure uniform and stable metal dispersion under harsh conditions, manage the complexity and cost of the preparation process, and, most importantly, optimize the catalytic performance. Thus, this general approach can improve the efficiency and practical application of industrial zeolite catalysts, thereby benefiting industrial furfural production.