Wang Lu, Liu Yi, Liu Xiaoheng, Chen Wei
Key Laboratory of Education Ministry Functional for Molecular Solids, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, China.
Key Laboratory of Education Ministry for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094, China.
Dalton Trans. 2023 Aug 29;52(34):12038-12048. doi: 10.1039/d3dt01814h.
Powder electrocatalysts for oxygen evolution reactions usually need adhesives for electrocatalytic performance tests, leading to the increase of resistance, reduction of catalyst loading, and easy stripping of the catalyst under long-time or high current operation. In this study, Ce-doped CoFe layered double hydroxides were uniformly grown on nickel foam by a one-step hydrothermal route. A nanostructured self-supported electrode Ce-CoFe-LDH/NF without adhesive was obtained directly, which has a regular nanoneedle morphology with a length of ∼1.2 μm and tip width of ∼20 nm. Adopting Ce ions with a large radius to partially displace Fe ions with a small radius produced lattice distortion and more defects in the host layer of CoFe-LDH, whereby possessing the great potential to enhance catalytic behaviors. Once used as an electrocatalyst for the oxygen evolution reaction, Ce-CoFe-LDH/NF shows an outstanding electrocatalytic performance, including an optimized overpotential of 225 mV at 10 mA cm, a decreased Tafel slope of 34.34 mV dec, and a low charge transfer impedance of 2.4 Ω in 1 M KOH electrolyte. Moreover, the overpotential of the working electrode increased by only 0.04 V after 24 hours and was maintained at a current density of 50 mA cm. These results demonstrate a low-cost strategy compared to using noble metal OER electrocatalysts. Thus, this study highlights a ready universal approach to fabricate high-performance supported catalysts for energy-related applications.
用于析氧反应的粉末电催化剂在进行电催化性能测试时通常需要粘合剂，这会导致电阻增加、催化剂负载量降低，并且在长时间或高电流操作下催化剂容易剥离。在本研究中，通过一步水热法将铈掺杂的钴铁层状双氢氧化物均匀生长在泡沫镍上。直接获得了一种无粘合剂的纳米结构自支撑电极Ce-CoFe-LDH/NF，其具有规则的纳米针形态，长度约为1.2μm，尖端宽度约为20nm。采用大半径的铈离子部分取代小半径的铁离子，在CoFe-LDH的主体层中产生晶格畸变和更多缺陷，从而具有增强催化性能的巨大潜力。一旦用作析氧反应的电催化剂，Ce-CoFe-LDH/NF表现出优异的电催化性能，包括在10 mA cm时优化的过电位为225 mV，Tafel斜率降低至34.34 mV dec，以及在1 M KOH电解液中的低电荷转移阻抗为2.4Ω。此外，工作电极在24小时后的过电位仅增加了0.04 V，并在50 mA cm的电流密度下保持稳定。这些结果表明，与使用贵金属析氧电催化剂相比，这是一种低成本策略。因此，本研究突出了一种现成的通用方法，可用于制备用于能源相关应用的高性能负载型催化剂。
