Li Xiaoge, Liu Cong, Fang Zhitang, Xu Lin, Lu Chunliang, Hou Wenhua
Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China.
School of Chemistry and Materials Science, Jiangsu Key Laboratory of New Power Batteries, Nanjing Normal University, Nanjing, 210023, P. R. China.
Small. 2022 Jan;18(2):e2104354. doi: 10.1002/smll.202104354. Epub 2021 Nov 12.
Water splitting is a promising sustainable technology to produce high purity hydrogen, but its commercial application remains a giant challenge due to the kinetically sluggish oxygen evolution reaction (OER). In this work, a time- and energy-saving approach to directly grow NiFe-layered double hydroxide (NiFe-LDH) nanosheets on nickel foam under ambient temperature and pressure is reported. These NiFe-LDH nanosheets are vertically rooted in nickel foam and interdigitated together to form a highly porous array, leading to numerous exposed active sites, reduced resistance of charge/mass transportation and enhanced mechanical stability. As self-supported electrocatalyst, the representative sample (NF@NiFe-LDH-1.5-4) shows an excellent large-current-density catalytic activity for OER in alkaline electrolyte, requiring low overpotentials of 190 and 220 mV to reach the current densities of 100 and 657 mA cm with a Tafel slope of 38.1 mV dec . In addition, NF@NiFe-LDH-1.5-4 as an overall water splitting electrocatalyst can stably achieve a large current density of 200 mA cm over 300 h at a low cell voltage of 1.83 V, meeting the requirement of industrial hydrogen production. This exceedingly simple and ultrafast synthesis of low-cost and highly active large-current-density OER electrocatalysts can propel the commercialization of hydrogen producing technology via water splitting.
水分解是一种很有前景的可持续技术，可用于生产高纯度氢气，但由于析氧反应（OER）的动力学缓慢，其商业应用仍然是一个巨大的挑战。在这项工作中，报道了一种在常温常压下直接在泡沫镍上生长镍铁层状双氢氧化物（NiFe-LDH）纳米片的省时节能方法。这些NiFe-LDH纳米片垂直扎根于泡沫镍中，并相互交错形成高度多孔的阵列，从而导致大量暴露的活性位点，降低了电荷/质量传输电阻并增强了机械稳定性。作为自支撑电催化剂，代表性样品（NF@NiFe-LDH-1.5-4）在碱性电解质中对OER表现出优异的大电流密度催化活性，在电流密度分别为100和657 mA cm时，达到该电流密度所需的过电位低至190和220 mV，塔菲尔斜率为38.1 mV dec 。此外，NF@NiFe-LDH-1.5-4作为全水解电催化剂，在1.83 V的低电池电压下，可在300 h内稳定地实现200 mA cm的大电流密度，满足工业制氢的要求。这种极其简单且超快合成低成本、高活性大电流密度OER电催化剂的方法可以推动通过水分解制氢技术的商业化。
