Liu Ji Kai, Kang Mengde, Huang Kai, Xu Hao Guan, Wu Yi Xiao, Zhang Xin Yu, Zhu Yan, Fan Hao, Fang Song Ru, Zhou Yi, Lian Cheng, Liu Peng Fei, Yang Hua Gui
Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China.
State Key Laboratory of Chemical Engineering, Shanghai Engineering Research Center of Hierarchical Nanomaterials, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China.
Nat Commun. 2025 Apr 11;16(1):3458. doi: 10.1038/s41467-025-58203-9.
The industrial implementation of coupled electrochemical hydrogen production systems necessitates high power density and high product selectivity for economic viability and safety. However, for organic nucleophiles (e.g., methanol, urea, and amine) electrooxidation in the anode, most catalytic materials undergo unavoidable reconstruction to generate high-valent metal sites under harsh operation conditions, resulting in competition with oxygen evolution reaction. Here, we present unique Ni(II) sites in Prussian blue analogue (NiFe-sc-PBA) that serve as stable, efficient and selective active sites for ethylene glycol (EG) electrooxidation to formic acid, particularly at ampere-level current densities. Our in situ/operando characterizations demonstrate the robustness of Ni(II) sites during EG electrooxidation. Molecular dynamics simulations further illustrate that EG molecule tends to accumulate on the NiFe-sc-PBA surface, preventing hydroxyl-induced reconstruction in alkaline solutions. The stable Ni(II) sites in NiFe-sc-PBA anodes exhibit efficient and selective EG electrooxidation performance in a coupled electrochemical hydrogen production flow cell, producing high-value formic acid compared to traditional alkaline water splitting. The coupled system can continuously operate at stepwise ampere-level current densities (switchable 1.0 or 1.5 A cm) for over 500 hours without performance degradation.
为了实现经济可行性和安全性，耦合电化学制氢系统的工业应用需要高功率密度和高产物选择性。然而，对于阳极中的有机亲核试剂（如甲醇、尿素和胺）的电氧化，大多数催化材料在苛刻的操作条件下会不可避免地发生重构，生成高价金属位点，从而导致与析氧反应产生竞争。在此，我们展示了普鲁士蓝类似物（NiFe-sc-PBA）中独特的Ni(II)位点，这些位点可作为乙二醇（EG）电氧化生成甲酸的稳定、高效且选择性的活性位点，特别是在安培级电流密度下。我们的原位/操作表征证明了Ni(II)位点在EG电氧化过程中的稳定性。分子动力学模拟进一步表明，EG分子倾向于在NiFe-sc-PBA表面积累，从而在碱性溶液中防止羟基诱导的重构。NiFe-sc-PBA阳极中稳定的Ni(II)位点在耦合电化学制氢流动池中表现出高效且选择性的EG电氧化性能，与传统碱性水分解相比，可产生高价值的甲酸。该耦合系统能够在逐步的安培级电流密度（可切换为1.0或1.5 A cm）下连续运行超过500小时而不发生性能下降。
