Zihao Zhang,Changxue Wang,Xin Gou,Hao Chen,Kequan Chen,Xiuyang Lu,Pingkai Ouyang,Jie Fu
A series of Cu-based catalysts with different supports were synthesized and studied for the in situ hydrogenation of 5-hydroxymethylfurfural (5-HMF) to dimethylfuran (DMF) using methanol as an economical hydrogen donor. The structures and properties of the four catalysts (Cu/Al 2 O 3 , Cu/ZnO, Cu/ZrO 2 , and Cu/CeO 2 ) were characterized using X-ray diffraction (XRD), temperature-programmed reduction (H 2 -TPR), and temperature-programmed desorption of ammonia (NH 3 -TPD). The experimental results showed that the use of different supports for the Cu-based catalysts significantly influenced their activity for both H 2 production from methanol and hydrogenation of 5-HMF. The catalyst Cu/Al 2 O 3 showed the best catalytic activity, which can be attributed to the highest activity for the in situ H 2 production from methanol, smallest Cu crystallite size, and strongest acidity. The effects of the substrate concentration, catalyst loading, and reaction temperature and time on the in situ hydrogenation of 5-HMF were systematically investigated to determine the optimum reaction conditions.
Cu/ZnO/Al2O3 (CZA) catalyst remains the benchmark for methanol synthesis but suffers from active-site sintering and insufficient CO2 activation. In this study, we proposed a dual strategy to enhance and regulate the active sites of CZA: hydrothermal treatment induces Cu–Zn coordination to create high-density Cu–ZnO1–x interfaces that promote CO2 conversion, while subsequent La doping regulates Cu0/Cu+ species to favor methanol selectivity. As a result, the maximum space-time yield (STY) of methanol over the designed CZA&5%La-LRCP (prepared by the ligand-regulated coprecipitation method) catalyst improved significantly from 283.0 gMeOH·kgcat–1·h–1 for the conventional coprecipitation-prepared CZA to 400.4 gMeOH·kgcat–1·h–1 under the tested conditions, surpassing most literature reports on La-doped Cu-based catalysts. Comprehensive characterizations and kinetic studies revealed that high-density Cu–ZnO1–x interfaces enhance CO2 adsorption and activation, while uniformly distributed electron-enriched Cu0/Cu+ species promote H2 dissociation and facilitate formate formation and transformation, together establishing an efficient pathway for CO2 activation and hydrogenation. This study demonstrates a promising strategy for the rational design of CO2hydrogenation catalysts through the synergistic modulation of interfacial structure and electronic properties.
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