Activating ruthenium dioxide via compressive strain achieving efficient multifunctional electrocatalysis for Zn-air batteries and overall water splitting

Surface strain engineering is a promising strategy to design various electrocatalysts for sustainable energy storage and conversion. However, achieving the multifunctional activity of the catalyst via the adjustment of strain engineering remains a major challenge. Herein, an excellent trifunctional electrocatalyst (Ru/RuO2@NCS) is prepared by anchoring lattice mismatch strained core/shell Ru/RuO2 nanocrystals on nitrogen-doped carbon nanosheets. Core/shell Ru/RuO2 nanocrystals with similar to 5 atomic layers of RuO2 shells eliminate the ligand effect and produce similar to 2% of the surface compressive strain, which can boost the trifunctional activity (oxygen evolution reaction [OER], oxygen reduction reaction [ORR], and hydrogen evolution reaction [HER]) of the catalyst. When equipped in rechargeable Zn-air batteries, the Ru/RuO2@NCS endows them with high power (137.1 mW cm(-2)) and energy (714.9 Wh kg(zn)(-1)) density and excellent cycle stability. Moreover, the as-fabricated Zn-air batteries can drive a water splitting electrolyzer assembled with Ru/RuO2@NCS and achieve a current density of 10 mA cm(-2) only requires a low potential similar to 1.51 V. Density functional theory calculations reveal that the compressive strained RuO2 could reduce the reaction barrier and improve the binding of rate-determining intermediates (*OH, *O, *OOH, and *H), leading to the enhanced catalytic activity and stability. This work can provide a novel avenue for the rational design of multifunctional catalysts in future clean energy fields.

Automated summary

Surface strain engineering is a promising strategy for designing electrocatalysts for sustainable energy storage and conversion. This study presents the preparation of a trifunctional electrocatalyst (Ru/RuO2@NCS) by anchoring lattice mismatch strained core/shell Ru/RuO2 nanocrystals on nitrogen-doped carbon nanosheets. The resulting catalyst exhibits high catalytic activity for the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER), enabling high power and energy density in rechargeable Zn-air batteries and achieving efficient water splitting. The compressive strained RuO2 in the catalyst reduces the reaction barrier and improves the binding of intermediates, leading to enhanced catalytic activity and stability.