合金相CuxCoy/CN催化CO2加氢合成乙醇

Catalysis of CO2 hydrogenation to ethanol over alloy phase CuxCoy/CN

摘要:

采用三聚氰胺做碳源和氮源,通过调变Cu、Co比例, 添加β-环糊精和EDTA,浸渍合成了Cu_xCo_y/CN, XRD、SEM-EDS、CO₂-TPD、H₂-TPR、氮气吸脱附、XPS以及拉曼光谱表征表明EDTA和环糊精的加入共同促进了金属在催化剂表面的分散性,4有利于CuCo合金相的形成,CN载体与金属之间相互作用能够提高材料表面的Lewis碱性位点,有效吸附CO₂并将其解离。研究了Cu_xCo_y/CN在固定床反应器中对CO₂加氢合成乙醇的活性,在H₂/CO₂=3:1,温度200 ℃, 压强2.0 MPa和空速12000 mL/(g_cat.h)时,Cu₂Co₁/CN具有最好的催化活性,CO₂单程转化率为9.3 %,乙醇选择性为18.0%。研究通过化学转化实现CO₂的减排,同时提供了新的乙醇生产途径,缓解日益紧张的粮食危机。

Abstract:

Cu_xCo_y/CN was synthesized using β-cyclodextrin and EDTA assisted impregnation using melamine serving as carbon and nitrogen sources. Techniques of XRD, SEM-EDS, CO₂-TPD, H₂-TPR, nitrogen adsorption/desorption, XPS and Raman spectroscopy indicated that the combined use of EDTA and β-cyclodextrin enhances the dispersion of metals on the surface and facilitates the formation of an alloy structure. The interaction between carbon nitride (CN) and metals can increase the Lewis basic sites on the catalyst surface, thereby effectively adsorb and dissociate the CO₂. The catalytic activity of Cu_xCo_y/CN for the synthesis of ethanol from CO₂ hydrogenation was investigated in a fixed-bed reactor. Under H₂/CO₂ ratio of 3:1, temperature of 200 °C, pressure of 2.0 MPa, and a gas flow rate of 12,000 mL/(g_cat.h), Cu₂Co₁/CN resulted in a CO₂ per-pass conversion of 9.3 %, and an ethanol selectivity of 18.0 %. This study contributes to the reduction of CO₂ emission through the chemical conversion, and offers a novel pathway for ethanol production, addressing the increasingly pressing food crisis.