Zhang Geng, Guo Wei, Zheng Hong, Li Xiang, Wang Jinxin, Zhang Qiuyu
Key Laboratory of Special Functional and Smart Polymer Materials of Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, China.
Nat Commun. 2024 Dec 30;15(1):10845. doi: 10.1038/s41467-024-55120-1.
Coordination complexes are promising candidates for powerful electrocatalytic oxygen evolution reaction but challenges remain in favoring the kinetics behaviors through local coordination regulation. Herein, by refining the synergy of carboxylate anions and multiconjugated benzimidazole ligands, we tailor a series of well-defined and stable coordination complexes with three-dimensional supramolecular/coordinated structures. The coordinated water as potential open coordination sites can directly become intermediates, while the metal center easily achieves re-coordination with water molecules in the pores to resist lattice oxygen dissolution. In situ experiments and theory simulations indicate that nickel centers with neighboring coordinated water molecules follow an intramolecular oxygen coupling mechanism with a low thermodynamic energy barrier. With more coordinated water introduced, an optimized intramolecular oxygen coupling process may appear for favoring the reaction kinetics. As such, a low overpotential of 248 mV at 10 mA cm and long-term stability of 200 h are achieved. This study underscores the potential of crafting coordinated water molecules for efficient electrocatalysis applications.
配位络合物是用于高效电催化析氧反应的有前景的候选物，但通过局部配位调控来促进动力学行为仍面临挑战。在此，通过优化羧酸根阴离子与多共轭苯并咪唑配体的协同作用，我们定制了一系列具有三维超分子/配位结构的明确且稳定的配位络合物。作为潜在开放配位点的配位水可直接成为中间体，而金属中心易于在孔中与水分子重新配位以抵抗晶格氧溶解。原位实验和理论模拟表明，具有相邻配位水分子的镍中心遵循具有低热力学能垒的分子内氧偶联机制。随着引入更多配位水，可能会出现优化的分子内氧偶联过程以促进反应动力学。因此，在10 mA cm时实现了248 mV的低过电位和200 h的长期稳定性。这项研究强调了构建配位水分子用于高效电催化应用的潜力。
