Modulating the Electrocatalytic Performance of Palladium with the Electronic Metal–Support Interaction: A Case Study on Oxygen Evolution Reaction

The present work reports a general approach to improve the electrocatalytic property of noble metal through regulating its electron status by introducing the electronic metal–support interaction (EMSI). As a case study, the catalytic activity of metallic Pd toward oxygen evolution reaction (OER) in alkaline solution has been significantly promoted by stabilizing Pdδ+ oxidic species at the interface of the Pd–metal oxide support with the help of EMSI effect, suggesting an intrinsic advantage of Pdδ+ in driving OER. We further demonstrate that the chemical state of Pdδ+ can be easily modulated in the range of 2+ to 3+ by changing the metal oxide support, interestingly, accompanied by a clear dependence of the OER activity on the oxidation state of Pdδ+. The high Pd3+ species-containing Fe2O3/Pd catalyst has fed an impressively enhanced OER property, showing an overpotential of 383 mV at 10 mA cm–2 compared to those of >600 mV on metallic Pd and 540 mV on Fe2O3/glassy carbon. The greatly enhanced OER performance is believed to primarily derive from the distinctive improvement in the adsorption of oxygenated intermediates (e.g., *OH and *OOH) on metal-oxide/Pd catalysts. Moreover, similar EMSI induced improvements in OER activity in alkaline solution are also achieved on both of the Fe2O3/Au and Fe2O3/Pt, which possess the oxidic species of Au3+, and Pt2+ and Pt4+, respectively.