Interface strain engineering of a Ru–RuOx/graphene aerogel composite boosts HER, OER and ORR applications

Abstract

Development of efficient and multifunctional catalysts is crucial for the continued advancement of various clean energy conversion (e.g., the HER, OER and ORR) applications. However, achieving high activity under multiple reaction conditions remains a formidable challenge. Ru-based catalysts possess specific HER, OER, and ORR performances due to the ability to modulate their electronic structure and can be considered as potential candidates for catalyzing multiple electrocatalytic reactions. Herein, we first use density-functional theory (DFT) calculations to predict the effect that interfacial Ru–RuO_x strain will have on the ability to catalyze multiple electrocatalytic reaction activities. Theoretical calculations confirm that the interfacial interaction between Ru and RuO_x leads to the elongation of the Ru–O bond, thereby promoting the optimization of electronic structure of the Ru sites and causing a negative shift of the d-band center, thus optimizing the adsorption of reaction intermediates and facilitating electrocatalytic reactions. After using this theoretical guidance for the synthesis of various catalysts, Ru–RuO_x/GA-2 is identified as the optimal catalyst, exhibiting outstanding HER, OER and ORR performance. The Ru–RuO_x/GA-2 catalyst achieves a current density of 10 mA cm⁻² at a low overpotential of only 17 mV in the HER and 268 mV in the OER. The catalyst also displays a high half-wave potential of 0.84 V for the ORR. The membrane electrode assembly (MEA) and Zn–air battery (ZAB) assembled based on Ru–RuO_x/GA-2 demonstrate excellent activity and cycling stability, highlighting their potential in clean energy conversion fields. This work provides important insights into the design and development of advanced single electrocatalysts with multiple electrocatalytic applications via interface strain engineering.