van den Bosch Bart, Rawls Brian, Brands Maria B, Koopman Christel, Phillips Matthew F, Figueiredo Marta C, Gruter Gert-Jan M
Renewable Chemistries, Avantium Chemicals, Science Park 408, 1098 XH, Amsterdam, The Netherlands.
Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
Chempluschem. 2023 Apr;88(4):e202300112. doi: 10.1002/cplu.202300112.
Electrocatalytic CO reduction processes are generally coupled with the oxidation of water. Process economics can greatly improve by replacing the water oxidation with a more valuable oxidation reaction, a process called paired electrolysis. Here we report the feasibility of pairing CO reduction with the oxidation of glycerol on Ni S /NF anodes to produce formate at both anode and cathode. Initially we optimized the oxidation of glycerol to maximize the Faraday efficiency to formate by using design of experiments. In flow cell electrolysis, excellent selectivity (up to 90 % Faraday efficiency) was achieved at high current density (150 mA/cm of geometric surface area). Then we successfully paired the reduction of CO with the oxidation of glycerol. A prerequisite for industrial application is to obtain reaction mixtures with a high concentration of formate to enable efficient downstream separation. We show that the anodic process is limited in formate concentration, as Faraday efficiency to formate greatly decreases when operating at 2.5 M formate (∼10 w%) in the reaction mixture due to over-oxidation of formate. We identify this as a major bottleneck for the industrial feasibility of this paired electrolysis process.
电催化CO还原过程通常与水的氧化相耦合。通过用更有价值的氧化反应取代水氧化（一种称为成对电解的过程），过程经济性可以大大提高。在此，我们报告了在Ni S/NF阳极上使CO还原与甘油氧化配对以在阳极和阴极均产生甲酸盐的可行性。最初，我们通过实验设计优化甘油的氧化，以使生成甲酸盐的法拉第效率最大化。在流动池电解中，在高电流密度（几何表面积为150 mA/cm²）下实现了优异的选择性（高达90%的法拉第效率）。然后，我们成功地使CO还原与甘油氧化配对。工业应用的一个先决条件是获得具有高浓度甲酸盐的反应混合物，以实现高效的下游分离。我们表明，阳极过程中甲酸盐浓度受到限制，因为当在反应混合物中2.5 M甲酸盐（约10 w%）下运行时，由于甲酸盐的过度氧化，生成甲酸盐的法拉第效率会大大降低。我们将此确定为这种成对电解过程工业可行性的一个主要瓶颈。
