Interface Engineering of Ru/RuO2 Heterostructures on Carbon Nanotubes for Efficient and Stable Acidic Oxygen Evolution

Abstract

The efficient and durable oxygen evolution reaction (OER) electrocatalysts are critical for enhancing proton exchange membrane water electrolyzer (PEMWE) performance. RuO2 has high intrinsic OER activity, but it is susceptible to oxidation into soluble RuO4− species in acidic electrolyte due to the highly reactive nature of lattice oxygen. Herein, we introduce an effective strategy aimed at bolstering structural stability by constructing Ru/RuO2 heterostructures onto carbon nanotubes (Ru/RuO2@CNT). The formation of Ru0−O−Ru4+ interfacial structures within these heterostructures effectively suppresses the Ru4+ oxidation state and simultaneously refines the d-band center of Ru sites for optimizing intermediates adsorption, thus accelerating the OER kinetics. Consequently, the Ru/RuO2@CNT-300 achieves a low overpotential of 169 mV at 10 mA cm−2 and displays remarkable durability exceeding 100 hours of stable operation in a 0.5 M H2SO4. The unique structure endows the Ru/RuO2@CNT-300 with exceptional acidic OER activity compared to most reported electrocatalysts. This work provides a feasible pathway for designing efficient and stable OER electrocatalysts for high-performance PEMWE.