Sun Yaxun, Wang Ze, Zhou Qianyu, Li Xin, Zhao Dongye, Ding Bo, Wang Shifeng
Key Laboratory of Plateau Oxygen and Living Environment of Tibet Autonomous Region, College of Science, Tibet University, Lhasa, 850000, China.
College of Information Engineering, Xizang Minzu University, Xianyang 712000, China.
Heliyon. 2024 May 14;10(10):e30966. doi: 10.1016/j.heliyon.2024.e30966. eCollection 2024 May 30.
Oxygen evolution reaction (OER) is a very complex process with slow reaction kinetics and high overpotential, which is the main limitation for the commercial application of water splitting. Thus, it is of necessary to design high-performance OER catalysts. NiFe based layered double hydroxides (NiFe-LDHs) have recently gained a lot of attention due to their high reaction activity and simple manufacturing process. In this study, a novel electrocatalyst based on NiFe-LDH was constructed by introducing TiC, which was utilized to modulate the structural and electronic properties of the electrocatalysts. Structural examinations reveal that the TiC of 2D structure successfully dope the NiFe-LDHs nanosheets, forming NiFe-LDH/TiC heterojunctions. Firstly, the heterojunction substantially reduces the charge transfer resistance, promoting the electron migration between the LDH nanosheets. Secondly, theoretical calculations demonstrate that the energy barrier between the rate-determining step from *OH to *O is lowered, favoring the formation of the reaction intermediates and thus the occurrence of OER. As a result, the composite electrocatalyst exhibits a low overpotential of 334 mV at a current density of 10 mA/cm and a small Tafel slope of 55 mV/dec, which are superior to those of the NiFe-LDH by 11.2 % and 38.5 %, respectively. This study provides inspiration for promoting the performances of NiFe based electrocatalysts by utilizing 2D materials.
析氧反应（OER）是一个非常复杂的过程，反应动力学缓慢且过电位高，这是水分解商业化应用的主要限制。因此，设计高性能的析氧反应催化剂是很有必要的。基于镍铁的层状双氢氧化物（NiFe-LDHs）由于其高反应活性和简单的制造工艺，最近受到了广泛关注。在本研究中，通过引入TiC构建了一种基于NiFe-LDH的新型电催化剂，用于调节电催化剂的结构和电子性质。结构检测表明，二维结构的TiC成功掺杂到NiFe-LDHs纳米片中，形成了NiFe-LDH/TiC异质结。首先，异质结显著降低了电荷转移电阻，促进了LDH纳米片之间的电子迁移。其次，理论计算表明，从OH到O的速率决定步骤之间的能垒降低，有利于反应中间体的形成，从而促进析氧反应的发生。结果，复合电催化剂在电流密度为10 mA/cm时表现出334 mV的低过电位和55 mV/dec的小塔菲尔斜率，分别比NiFe-LDHs的性能高出11.2%和38.5%。本研究为利用二维材料提高镍铁基电催化剂的性能提供了思路。
