Glycerol, a byproduct of biodiesel production, is a promising feedstock for conversion into high-value products through the glycerol electrochemical oxidation reaction (GEOR). Herein, a Ni-based layered double hydroxide (Ni LDH) catalyst is synthesized via hydrothermal synthesis to investigate the mechanism of the selective conversion of glycerol to formic acid (FA). The Ni LDH exhibits not only a high conversion rate of glycerol but also higher selectivity and Faradaic efficiency for FA at low potentials compared to NiFe LDHs. Through density functional theory (DFT) calculations, the delocalization of the π-type bond between the adsorbed intermediate, glyceric acid (GLA), and the catalyst surface is found to activate GLA, leading to the preferential formation of FA through C–C bond cleavage at low potentials. Furthermore, with an understanding of the roles of OH^– and glycerol concentrations in GEOR, controlling KOH and glycerol concentrations proves to be an effective way to enhance the selectivity and Faradaic efficiency of FA for the Ni LDH catalyst.

中文翻译：

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通过甘油电氧化在 Ni 和 NiFe 层状氢氧化物中选择性生产甲酸


甘油是生物柴油生产的副产品，是一种很有前景的原料，可通过甘油电化学氧化反应 (GEOR) 转化为高价值产品。在此，通过水热合成法合成了镍基层状双氢氧化物（Ni LDH）催化剂，以研究甘油选择性转化为甲酸（FA）的机理。与 NiFe LDH 相比，Ni LDH 不仅具有较高的甘油转化率，而且在低电位下对 FA 具有更高的选择性和法拉第效率。通过密度泛函理论（DFT）计算，发现吸附中间体甘油酸（GLA）与催化剂表面之间π型键的离域作用激活了GLA，导致通过C-C键优先形成FA低电位裂解。此外，通过了解 OH ^– 和甘油浓度在 GEOR 中的作用，控制 KOH 和甘油浓度被证明是提高 Ni LDH 催化剂 FA 选择性和法拉第效率的有效方法。