MOFs derived acid-base regulation strategies of CuZnAl catalyst for boosting CO2 hydrogenation to methanol

Abstract

Acid-base synergistic effect is crucial in adjusting the catalytic performance of CO₂ hydrogenation to methanol, an efficient CO₂ emission reduction and carbon recycle strategy. Two MOFs-derived catalysts (CZ-MIL, CA-ZIF) with opposite acid-base properties were tailored by using MIL-68 (Al) and ZIF-8 (Zn) as precursors, and the above two MOFs precursors were hybridized (C-ZAx) to control the acid-base property of the catalyst. C-ZA0.6 (molar ratio of MIL-68 (Al) to ZIF-8 (Zn)=0.6) exhibits a promising catalytic performance with CO₂ conversion of 8.9 %, methanol selectivity of 61.85 %, and STY of 117.02 mg mL⁻¹·h⁻¹ at 4 MPa and 523 K. Combined with comprehensive analysis, it is found that methanol selectivity is closely related to weak acid sites arising from the residual skeleton of MIL-68. Acid-base synergy facilitates the hydrogenation of CO₂ to methanol. The basic sites are responsible for adsorbing and activating CO₂, and the acidic site helps to stabilize CO* and facilitate the further hydrogenation to methanol. This work provides a new idea and feasible method for enhancing the catalytic performance of CO₂ hydrogenation to methanol.