碳负载Cu-Bi双金属高效电催化CO_(2)还原制备乙醇

Highly efficient electrochemical CO_(2)reduction to ethanol on carbon supported Cu-Bi bimetallic catalyst

采用清洁电能驱动CO_(2)转化为碳氢燃料及高价值的化学品是实现“碳中和”最有应用前景的方式之一。在电催化还原CO_(2)的产物中,乙醇是极具吸引力的产物。Cu基催化剂具有良好电催化还原CO_(2)至C_(2+)产物的活性,但单一的Cu基催化剂不稳定,极易容易被氧化,因而可能严重降低电化学还原的电流密度及催化剂活性。本研究采用“一锅法”合成碳负载Cu-Bi双金属催化剂(Cu_(x)Bi_(y)@C)。在0.1 mol/L KCHO_(3)溶液中,CuxBiy@C表现出良好的电催化还原CO_(2)的活性,乙醇产物的选择性接近~100%。在-0.37 V(vs. RHE)过电位下CO_(2)还原为乙醇的法拉第效率可达到76.7%,其生成速率为450.6μmol g^(-1) h^(-1),催化剂在持续10 h的电催化还原过程中保持了良好的稳定性。动力学结果表明Cu、Bi双位点协同有利于质子/电子耦合转移,因而促进C-C偶联生成乙醇。

Electrochemical CO_(2)conversion into hydrocarbon fuels and high-value chemicals is one of the most promising ways to achieve“carbon neutrality”.Ethanol is one of the most attractive products in electrocatalytic CO_(2)reduction.Cu-based catalysts exhibit the good activity on electrochemical CO_(2)reduction into C^(2+)products,but suffer from the accessible oxidation in the process.The performance therefore probably dramatically decreases.Herein,a carbon-supported Cu-Bi bimetallic catalyst(Cu_(x)Bi_(y)@C)was synthesized by a simple one-pot method.The catalyst exhibited the superior activity on electrochemical CO_(2)reduction into ethanol with almost~100%selectivity in 0.1 mol·L^(-1)KCHO_(3) solution.At-0.37 V(vs.RHE)overpotential,the Faraday efficiency of CO_(2)reduction to ethanol reached 76.7%,and the formation rate was 450.6μmol g^(-1)h^(-1).The catalyst maintained the good stability in the electrocatalytic reduction process for consecutive 10 h.Kinetic results show that the synergy of Cu and Bi sites are conducive to proton/electron coupling transfer,and promote C-C coupling to ethanol.