Promoting electrocatalytic hydrogenation of 5-hydroxymethylfurfural using buffer electrolytes as proton-donating motifs: Theoretical predictions and experimental validations
Promoting electrocatalytic hydrogenation of 5-hydroxymethylfurfural using buffer electrolytes as proton-donating motifs: Theoretical predictions and experimental validations
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DOI：
10.1016/j.apcatb.2022.122191
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发表时间：
2022-11-17
影响因子：
22.1
通讯作者：
Yu, Han-Qing
中科院分区：
文献类型：
--
作者：
Pan, Xiao-Qiang;Zhang, Xin-Yu;Yu, Han-Qing
电催化加氢（ECH）是一种很有前途的替代高压氢气加氢技术的方法。质子供给基序是决定反应效率的重要因素，但在ECH过程中通常被忽视。在此，密度泛函理论（DFT）的预测和实验验证的基础上，我们表明，质子缓冲盐，如磷酸盐，碳酸盐和硼酸盐可以大大提高ECH的效率。DFT结果表明，缓冲剂能通过Langmuir-Hinshelwood或质子耦合电子转移（PCET）机理为羰基化合物的加氢提供质子，从而促进羰基化合物的加氢.实验结果表明，在近中性缓冲电解液中，Co 3 O 4纳米阵列催化剂可有效地将5-羟甲基糠醛（HMF）转化为具有附加值的2，5-二羟甲基呋喃（DHMF），转化率可达96%以上，产率可达80%。原位拉曼光谱分析和动力学同位素实验结果表明，该反应的真实的机理是Langmuir-Hinshelwood和PCET过程的结合。这种缓冲促进策略在具有不同电极催化剂的各种其他羰基化合物的ECH中也表现出广泛的适用性。这项工作可能会提供一个深刻的理解的ECH过程，并开辟了新的机会，设计有效的系统转化为增值产品的HMF。
Electrocatalytic hydrogenation (ECH) represents a promising alternative to conventional hydrogenation tech-niques with high-pressure H2 as a reductant. The proton-donating motif is an important factor governing the reaction efficiency but is usually overlooked in the ECH process. Herein, on the basis of density functional theory (DFT) predictions and experimental validations, we demonstrate that proton-buffer salts such as phosphate, carbonate and borate can greatly promote ECH efficiency. The DFT results predict that the buffer species can outperform water in donating protons for *C--O hydrogenation into *C-OH via the Langmuir-Hinshelwood or proton-coupled electron transfer (PCET) mechanism, thus promoting the hydrogenation of carbonyl compounds. The experimental results demonstrate that with the buffer-promoting effects, 5-hydroxymethylfurfural (HMF) can be effectively converted at an efficiency of 96 % into the value-added 2,5-dihydroxymethylfuran (DHMF) with a yield of 80 % over cobalt oxide (Co3O4) nanoarray catalysts under near-neutral buffer electrolyte. In situ Raman analysis and kinetic isotope experimental results reveal that the real mechanism is a combined Langmuir-Hinshelwood and PCET process. Such a buffer-promoting strategy also exhibits wide applicability in ECH of various other carbonyl compounds with different electrode catalysts. This work may provide a deep under-standing of the ECH process and open up new opportunities to design effective systems for the conversion of HMF into value-added products.