摘要
析氧反应(OER)电催化剂的本征活性及稳定性主要取决于活性材料的表界面性能.本文采用两步水热法制备了一种新型核壳异质结构电催化剂(NF/NiSe@Fe_(2)O_(3)).该催化剂在1 mol L^(-1)的KOH介质中,电流密度为10或200 mA cm^(-2)时,析氧反应过电位分别低至220和282 mV,同时还具有较小的Tafel斜率(36.9 mV dec^(-1))及良好的长期稳定性(~230h).X射线光电子能谱和X射线吸收光谱表明,NF/NiSe@Fe_(2)O_(3)异质结构一方面具有高度羟基化的表面,同时由于在NiSe和Fe_(2)O_(3)的界面处形成Fe-Se键而具有较强的界面耦合作用.密度泛函理论计算进一步证实,Fe-Se键的形成导致了NiSe@Fe_(2)O_(3)异质结d带中心的移动并很好地优化了其电子结构,从而促进了析氧反应过程中含氧中间体的吸附及O_(2)的脱附,极大增强了催化剂的OER活性.另外,其独特的核壳结构及较强的界面耦合作用有效提升了催化剂的长期稳定性.该研究为界面键合效应对电催化剂OER性能的影响提供了一些基本认识.
The intrinsic activity and durability of oxygen evolution reaction(OER)electrocatalysts are mainly dominated by the surface and interface properties of active materials.Herein,a core-shell heterogeneous structure(NF/NiSe@Fe_(2)O_(3))is fabricated via two-step hydrothermal method,which exhibits a low overpotential of 220 mV(or 282 mV)at 10 mA/cm^(2)(or 200 mA/cm^(2)),a small Tafel slope of 36.9 mV/dec,and long-term stability(-230 h)in 1 mol/L KOH for OER.X-ray photoelectron spectroscopy and X-ray absorption spectroscopy reveal the(oxy)hydroxide-rich surface and strong coupling interface between NiSe and Fe_(2)O_(3)via the Fe-Se bond.Density functional theory calculation suggests that the d-band center and electronic state of NiSe@Fe_(2)O_(3)heterojunction are well optimized due to the formation of Fe-Se bond,which is favorable for the enhanced OER activity because of the easy adsorption of oxygen-containing intermediates and desorption of O^(2)in the OER process.In addition,the unique core-shell structure and robust bonding interface are responsible for the good stability for OER.This work provides fundamental insights on the bonding effect that determine the performance of OER electrocatalyst.
作者
郭凯璐
王彦涛
杨思卓
黄俊峰
邹泽华
潘海瑞
Pravin S.Shinde
潘善林
黄吉儿
徐彩玲
Kailu Guo;Yantao Wang;Sizhuo Yang;Junfeng Huang;Zehua Zou;Hairui Pan;Pravin S.Shinde;Shanlin Pan;Jier Huang;Cailing Xu(State Key Laboratory of Applied Organic Chemistry,Laboratory of Special Function Materials and Structure Design of the Ministry of Education,College of Chemistry and Chemical Engineering,Lanzhou University,Lanzhou 730000,China;Department of Chemistry,Marquette University,Milwaukee,WI 53201,USA;Department of Chemistry and Biochemistry,The University of Alabama,Tuscaloosa,AL 35487,USA)
基金
supported by the National Natural Science Foundation of China (21673105)
the support received from NSF under the award numbers OIA-1539035 and CHE-1539035
supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award No. DE-AC02-06CH11357
