Linghu Jiangtao, Zhang Yujuan, Hu Tuoping
Department of Chemistry, School of Chemistry and Chemical Engineering, North University of China, Taiyuan 030051, PR China.
Department of Chemistry, School of Chemistry and Chemical Engineering, North University of China, Taiyuan 030051, PR China.
J Colloid Interface Sci. 2025 Feb;679(Pt A):90-99. doi: 10.1016/j.jcis.2024.09.230. Epub 2024 Sep 30.
The integration of methanol oxidation reaction (MOR) with hydrogen evolution reaction (HER) represents an advanced approach to hydrogen production technology. Nonetheless, the rational design and synthesis of bifunctional catalysts for both MOR and HER with exceptional activity, stability and selectivity present formidable challenges. In this work, firstly, density functional theory (DFT) was utilized to design and evaluate material models with high performance for both MOR and HER. Secondly, guided by DFT, CoNi/CC (CC, carbon cloth) composites with a leaf-like nanosheet structure were successfully fabricated via electrodeposition. In the MOR process, Ni acts as the predominant active center, while Co amplifies the electrochemically active surface area (ECSA) and enhances the selectivity of methanol oxidation. Conversely, in the HER process, Co serves as the primary active center, with Ni augmenting the charge transfer rate. The electrochemical results demonstrate that CoNi/CC exhibits exceptional performance in both MOR and HER at a current density (j) of 10 mA cm, with peak potentials of 1.323 V and -95 mV, respectively. Additionally, it shows remarkable selectivity for the oxidiation of methanol to high value-added formic acid. Thirdly, following a 100 h chronopotentiometry (CP) test, the required potential demonstrates an increase of 4.9 % (MOR) and 8.1 % (HER), signifying the superior stability of CoNi/CC compared to those reported in the literature. The exceptional performance of CoNi/CC can be primarily attributed to that the leaf-like nanosheets structure not only exposes a plethora of active sites but also facilitates electrolyte diffusion, the monolithic structure prepared by electrodeposition enhances its stability, and the transfer of electrons from Co to Ni regulates its electronic structure, as corroborated by X-ray photoelectron spectroscopy (XPS) and density of states (DOS) analyses. Finally, at the same j, the voltage required by the CoNi/CC||CoNi/CC electrolytic cell, powered by an electrochemical workstation, is 198 mV lower than that required for alkaline water-splitting. Meanwhile, at higher j (100 mA cm), the electrolytic cell exhibits sustained and stable operation for 150 h, enabling high-efficiency hydrogen production and the synthesis of high value-added formic acid.
将甲醇氧化反应（MOR）与析氢反应（HER）相结合是制氢技术的一种先进方法。尽管如此，合理设计和合成兼具出色活性、稳定性和选择性的用于MOR和HER的双功能催化剂仍面临巨大挑战。在这项工作中，首先，利用密度泛函理论（DFT）设计和评估对MOR和HER均具有高性能的材料模型。其次，在DFT的指导下，通过电沉积成功制备了具有叶状纳米片结构的CoNi/CC（CC，碳布）复合材料。在MOR过程中，Ni作为主要活性中心，而Co扩大了电化学活性表面积（ECSA）并提高了甲醇氧化的选择性。相反，在HER过程中，Co作为主要活性中心，Ni提高了电荷转移速率。电化学结果表明，CoNi/CC在电流密度（j）为10 mA cm时，在MOR和HER中均表现出优异性能，峰值电位分别为1.323 V和 -95 mV。此外，它对甲醇氧化为高附加值甲酸表现出显著的选择性。第三，经过100 h的计时电位法（CP）测试后，所需电位显示MOR增加了4.9%，HER增加了8.1%，这表明CoNi/CC与文献报道的相比具有更高的稳定性。CoNi/CC的优异性能主要归因于叶状纳米片结构不仅暴露了大量活性位点，还促进了电解质扩散，电沉积制备的整体结构增强了其稳定性，以及从Co到Ni的电子转移调节了其电子结构，这得到了X射线光电子能谱（XPS）和态密度（DOS）分析的证实。最后，在相同的j下，由电化学工作站供电的CoNi/CC||CoNi/CC电解池所需电压比碱性水分解所需电压低198 mV。同时，在较高的j（100 mA cm）下，电解池可持续稳定运行150 h，实现了高效制氢和高附加值甲酸的合成。
