Hao Leilei, Ren Qinghui, Yang Jiangrong, Luo Lan, Ren Yue, Guo Xinyue, Zhou Hua, Xu Ming, Kong Xianggui, Li Zhenhua, Shao Mingfei
State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China.
Quzhou Institute for Innovation in Resource Chemical Engineering, Quzhou 324000, China.
ACS Appl Mater Interfaces. 2023 Mar 15;15(10):13176-13185. doi: 10.1021/acsami.3c00292. Epub 2023 Mar 3.
Electrocatalytic hydrogenation (ECH) of oxalic acid (OX) to produce glycolic acid (GA), an important building block of biodegradable polymers as well as application in various branches of chemistry, has attracted extensive attention in the industry, while it still encounters challenges of low reaction rate and selectivity. Herein, we reported a cation adsorption strategy to realize the efficient ECH of OX to GA by adsorbing Al ions on an anatase titanium dioxide (TiO) nanosheet array, achieving 2-fold enhanced GA productivity (1.3 vs 0.65 mmol cm h) with higher Faradaic efficiency (FE) (85 vs 69%) at -0.74 V vs RHE. We reveal that the Al adatoms on TiO both act as electrophilic adsorption sites to enhance the carbonyl (C═O) adsorption of OX and glyoxylic acid (intermediate) and also promote the generation of reactive hydrogen (H*) on TiO, thus promoting the reaction rate. This strategy is demonstrated effective for different carboxylic acids. Furthermore, we realized the coproduction of GA at the bipolar of a H-type cell by pairing ECH of OX (at cathode) and electrooxidation of ethylene glycol (at anode), demonstrating an economical manner with maximum electron economy.
草酸（OX）的电催化氢化（ECH）制备乙醇酸（GA），乙醇酸是可生物降解聚合物的重要组成部分，在化学的各个分支中都有应用，这在工业上引起了广泛关注，但其仍面临反应速率低和选择性差的挑战。在此，我们报道了一种阳离子吸附策略，通过在锐钛矿型二氧化钛（TiO₂）纳米片阵列上吸附铝离子来实现OX高效电催化氢化为GA，在相对于可逆氢电极（RHE）为-0.74 V时，乙醇酸生产率提高了2倍（1.3对0.65 mmol cm⁻² h⁻¹），法拉第效率（FE）更高（85%对69%）。我们发现TiO₂上的铝原子既作为亲电吸附位点增强了OX和乙醛酸（中间体）的羰基（C═O）吸附，又促进了TiO₂上活性氢（H*）的生成，从而提高了反应速率。该策略对不同的羧酸均有效。此外，我们通过将OX的电催化氢化（在阴极）与乙二醇的电氧化（在阳极）配对，在H型电池的双极实现了GA的联产，展示了一种具有最大电子经济性的经济方式。
