Density functional theory study of furfural electrochemical oxidation on the Pt (1 1 1) surface
Density functional theory study of furfural electrochemical oxidation on the Pt (1 1 1) surface
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DOI：
10.1016/j.jcat.2019.04.012
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发表时间：
2019-05
影响因子：
7.3
通讯作者：
Li Gong;N. Agrawal;A. Román;Adam Holewinski;M. Janik
中科院分区：
文献类型：
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作者：
Li Gong;N. Agrawal;A. Román;Adam Holewinski;M. Janik
糠醛的电氧化可以通过改变电极电位来调节产物的选择性。应用密度泛函理论（DFT）研究了Pt（1 1 1）表面的电催化氧化机理。报道了糠醛电催化氧化制糠酸、丁二酸、马来酸和马来酸酐的反应自由能谱。在比较了几种可能的糠醛氧化途径后，我们得出结论，糠醛的电氧化优先进行到呋喃酸，进一步的氧化由于难以单键dc键解离而减慢。超越呋喃酸的氧化可以进行到琥珀酸通过a2(3H)-呋喃酮作为中间体，马来酸和马来酸酐通过a2(5H)-呋喃酮作为中间体。这些过程的速率可能受到呋喃酸脱羧的限制。基本步热力学和动力学的DFT分析表明，呋喃酸、琥珀酸、马来酸或其他氧化产物之间的选择性可以通过改变电极电位来调节。初步实验结果表明，在0.9 V-RHE条件下，呋喃酸是铂电极上最显著的产物（选择性为bbb80 %），与DFT结果一致。这些结果拓宽了我们对糠醛电催化氧化的基本认识，这适用于可再生生物质衍生物的升级。
Electro-oxidation of furfural may allow for tunability of product selectivity by varying the electrode potential. We have applied density functional theory (DFT) to investigate the electrocatalytic oxidation mechanism on the Pt (1 1 1) surface. The potential-dependent reaction free energy profiles for furfural electrocatalytic oxidation to furoic acid, succinic acid, maleic acid, and maleic anhydride are reported. After comparing several possible furfural oxidation paths, we conclude that the electro-oxidation of furfural preferentially proceeds to furoic acid, with further oxidation slowed by difficult Csingle bondC bond dissociation. Oxidation beyond furoic acid can proceed to succinic acid via2(3H)-furanone as an intermediate and to maleic acid and maleic anhydride via2(5H)-furanone as an intermediate. The rate of these processes is likely limited by the decarboxylation of furoic acid. DFT analysis of elementary step thermodynamics and kinetics suggests that the selectivity between furoic acid, succinic acid, maleic acid, or other oxidized products is tunable by varying the electrode potential. Initial experimental results show furoic acid as the most significant product (>80% selectivity) at 0.9 V-RHE on a Pt electrode, in agreement with DFT results. These results broaden our fundamental understanding into electrocatalytic oxidation of furfural, which is applicable in upgrading renewable biomass derivatives.