共掺杂策略开发高效的钙钛矿析氧反应催化剂

Fe-Ni co-Doping Strategy in Perovskite for Developing an Efficient Oxygen Evolution Electrocatalyst

析氧反应的高反应势垒一直是水分解反应的瓶颈,目前迫切需要低成本、高性能且稳定的催化剂.本文采用共掺杂策略设计了一种有效的析氧反应电催化剂BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ).当电流密度在10 mA/cm^(2)时,BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ)的过电位为310 mV,Tafel斜率为50.2 mV/dec.BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ)的催化性能比Fe掺杂的BaCo_(0.8)Fe_(0.2)O_(3−δ)(BCF 360 mV)、Ni掺杂的BaCo_(0.8)Ni_(0.2)O_(3−δ)(375 mV)和IrO_(2)(329 mV)要好得多同时,BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ)也是一种比较稳定的碱性析氧反应催化剂.经过500次循环扫描,BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ)仍然表现出良好的催化活性,催化性能没有明显下降.电化学实验表明,BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ)在本文研究的材料中具有最快的反应动力学特征和最低的电荷转移电阻.此外,BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ)表面大量的高氧活性物种O_(2)^(2-)/O^(-)和羟基OH^(-)物种有利于析氧反应的发生,从而提高了反应速率.该研究为高性能电催化剂的开发提供了一种通用策略.

The high reaction barrier of the oxygen evolution reaction(OER)has always been the bottleneck of the water decomposition reaction,so low-cost,high-performance and stable catalysts are urgently needed currently.Herein,we designed an effective OER electrocatalyst BaCo_(0.6)Fe_(0.2)Ni_(0.2)O_(3−δ)(BCFN)by a codoping strategy.The overpotential of BCFN at a current density of 10 mA/cm^(2) reaches 310 mV,and possesses a Tafel slope of 50.2 mV/dec.The catalytic capability of BCFN is much stronger than that of Fe-doped BaCo_(0.8)Fe_(0.2)O_(3−δ)(360 mV),Ni-doped BaCo_(0.8)Ni_(0.2)O_(3−δ)(375 mV),and benchmark IrO_(2) with excellent performance(329 mV).At the same time,BCFN is also a fairly stable alkaline OER catalyst.After 500-cycle scans,BCFN still shows high catalytic activity without significant decrease in catalytic performance.Electrochemical experiments show that BCFN has the fastest reaction kinetics and the lowest charge transfer resistance among the materials in this work.In addition,a large amount of highly oxidative oxygen O_(2)^(2−)/O^(−)and hydroxyl groups OH^(−)on the surface of BCFN are conducive to the occurrence of OER,thereby increasing the reaction rate.This work provides a universal strategy to develop high-performance electrocatalysts for electrochemical energy conversion technology.