Wang Ze, Zhou Qianyu, Zhu Yanni, Du Yangfan, Yang Weichun, Chen Yuanfu, Li Yong, Wang Shifeng
Innovation Laboratory of Materials for Energy and Environment Technologies, Institute of Oxygen Supply, Tibet University, Lhasa 850000, China.
Key Laboratory of Cosmic Rays, Tibet University, Ministry of Education, Lhasa 850000, China.
Nanomaterials (Basel). 2022 Jun 27;12(13):2200. doi: 10.3390/nano12132200.
Currently, precious metal group materials are known as the efficient and widely used oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalysts. The exorbitant prices and scarcity of the precious metals have stimulated scale exploration of alternative non-precious metal catalysts with low-cost and high performance. Layered double hydroxides (LDHs) are a promising precursor to prepare cost-effective and high-performance catalysts because they possess abundant micropores and nitrogen self-doping after pyrolysis, which can accelerate the electron transfer and serve as active sites for efficient OER. Herein, we developed a new highly active NiFeMn-layered double hydroxide (NFM LDH) based electrocatalyst for OER. Through building NFM hydroxide/oxyhydroxide heterojunction and incorporation of conductive graphene, the prepared NFM LDH-based electrocatalyst delivers a low overpotential of 338 mV at current density of 10 mA cm with a small Tafel slope of 67 mV dec, which are superior to those of commercial RuO catalyst for OER. The LDH/OOH heterojunction involves strong interfacial coupling, which modulates the local electronic environment and boosts the kinetics of charge transfer. In addition, the high valence Fe and Mn species formed after NaOH treatment provide more active sites and promote the Ni to higher oxidation states during the O evolution. Moreover, graphene contributes a lot to the reduction of charge transfer resistance. The combining effects have greatly enhanced the catalytic ability for OER, demonstrating that the synthesized NFM LDH/OOH heterojunction with graphene linkage can be practically applied as a high-performance electrocatalyst for oxygen production via water splitting.
目前，贵金属基材料是已知的高效且广泛应用的析氧反应（OER）和析氢反应（HER）催化剂。贵金属的高昂价格和稀缺性促使人们大规模探索低成本、高性能的替代非贵金属催化剂。层状双氢氧化物（LDHs）是制备具有成本效益和高性能催化剂的有前途的前驱体，因为它们具有丰富的微孔，并且在热解后会发生氮自掺杂，这可以加速电子转移并作为高效OER的活性位点。在此，我们开发了一种新型的基于高活性NiFeMn层状双氢氧化物（NFM LDH）的OER电催化剂。通过构建NFM氢氧化物/羟基氧化物异质结并引入导电石墨烯，制备的基于NFM LDH的电催化剂在电流密度为10 mA cm时具有338 mV的低过电位和67 mV dec的小塔菲尔斜率，这优于用于OER的商业RuO催化剂。LDH/OOH异质结涉及强界面耦合，它调节局部电子环境并促进电荷转移动力学。此外，NaOH处理后形成的高价Fe和Mn物种提供了更多的活性位点，并在析氧过程中促进Ni达到更高的氧化态。此外，石墨烯对降低电荷转移电阻有很大贡献。这些综合效应大大增强了OER的催化能力，表明合成的具有石墨烯连接的NFM LDH/OOH异质结可实际用作通过水分解制氧的高性能电催化剂。
