Er-Doping Enhances the Oxygen Evolution Performance of Cobalt Oxide in Acidic Medium

High Resolution Image Download MS PowerPoint Slide Exploring highly active and durable non-noble electrocatalysts for acidic oxygen evolution reaction (OER) is critical for advancing H 2 production via water electrolysis using proton exchange membrane electrolyzer. However, it remains an immense challenge. Herein, we propose a strategy to synergistically enhance catalytic activity through Er doping, thereby enhancing both the intrinsic OER activity and stability of Co 3 O 4 . The cost-effective Er–Co 3 O 4 catalyst with 4% Er demonstrates significantly improved performance with an overpotential of 321 ± 5 mV at 10 mA cm –2 and exceptional stability exceeding 250 h. Additionally, doping Er into Co 3 O 4 induces structure defects to generate oxygen vacancies, increasing the ratio of Co 3+ /Co 2+ . In situ Raman analyses showed that during the OER process, there was an increase in Co–O active species at octahedral sites in 4% Er–Co 3 O 4, indicating accelerated generation of the key *O intermediates for enhanced OER kinetics. Microkinetic modeling and density functional theory calculations further demonstrate an optimized G O -G HO value at Er–Co 3 O 4, which is close to the theoretical optimal OER activity at the current density of interest. This study not only develops a cost-effective electrocatalyst for acidic OER but also provides fundamental insights into manipulating the structure of Co 3 O 4 for water electrolysis.