Chen Jiexin, Long Qingwu, Xiao Kang, Ouyang Ting, Li Nan, Ye Siyu, Liu Zhao-Qing
School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials/Guangzhou Key Laboratory for Clean Energy and Materials, Guangzhou University, Guangzhou 510006, China.
School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials/Guangzhou Key Laboratory for Clean Energy and Materials, Guangzhou University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Petrochemical Pollution Process and Control, Guangdong University of Petrochemical Technology, Maoming 525000, China.
Sci Bull (Beijing). 2021 Jun 15;66(11):1063-1072. doi: 10.1016/j.scib.2021.02.033. Epub 2021 Mar 2.
Layered double hydroxides (LDHs) with decent oxygen evolution reaction (OER) activity have been extensively studied in the fields of energy storage and conversion. However, their poor conductivity, ease of agglomeration, and low intrinsic activity limit their practical application. To date, improvement of the intrinsic activity and stability of NiFe-LDHs through the introduction of heteroatoms or its combination with other conductive substrates to enhance their water-splitting performance has drawn increasing attention. In this study, vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes (NiFeP/MXene) were successfully synthesised through a hydrothermal reaction and phosphating calcination process. The optimised NiFeP/MXene exhibited a low overpotential of 286 mV at 10 mA cm and a Tafel slope of 35 mV dec for the OER, which exceeded the performance of several existing NiFe-based catalysts. NiFeP/MXene was further used as a water-splitting anode in an alkaline electrolyte, exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 mA cm. Density functional theory (DFT) calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to promote the energy level of the d-band centre, resulting in an enhanced OER performance. This study provides a valuable guideline for designing high-performance MXene-supported NiFe-based OER catalysts.
具有良好析氧反应（OER）活性的层状双氢氧化物（LDHs）在能量存储和转换领域得到了广泛研究。然而，其导电性差、易团聚以及本征活性低限制了它们的实际应用。迄今为止，通过引入杂原子或与其他导电基底结合来提高NiFe-LDHs的本征活性和稳定性以增强其析氢性能已引起越来越多的关注。在本研究中，通过水热反应和磷化煅烧过程成功合成了生长在碳化钛薄片（NiFeP/MXene）表面的垂直交错三元磷化镍/铁杂化物。优化后的NiFeP/MXene在10 mA cm时表现出286 mV的低过电位和35 mV dec的塔菲尔斜率用于OER，超过了几种现有镍铁基催化剂的性能。NiFeP/MXene进一步用作碱性电解质中的析氢阳极，在电流密度为10 mA cm时仅表现出1.61 V的电池电压。密度泛函理论（DFT）计算表明，作为导电基底的MXene与磷化过程的结合可以有效地调节电催化剂表面的电子结构和密度，以促进d带中心的能级，从而提高OER性能。本研究为设计高性能MXene负载的镍铁基OER催化剂提供了有价值的指导。
