Novel Stable Co3O4-SnO2 Heterojunction Electrocatalysts with Low Oxygen Evolution Potential

Abstract

Proton exchange membrane (PEM) water electrolysis offers a sustainable route for hydrogen production, yet the reliance on costly noble metal-based anodes hinders scalability. Tin dioxide (SnO2) emerges as a promising alternative due to its acid stability, but its high oxygen evolution potential (OEP) limits practical application in hydrogen production via water electrolysis. Here, we address this challenge by incorporating cobalt (Co) into SnO2 to create a heterojunction electrocatalyst. The optimized Co3O4-SnO2 heterojunction catalyst with a tin-to-cobalt mass ratio of 3:1 exhibits a significantly reduced OEP (1.6 V vs. RHE) and an overpotential of 186 mV at 10 mA cm−2 in acidic media, outperforming undoped SnO2. Stability tests reveal a lifespan exceeding 24 h at 100 mA cm−2, a threefold improvement over pure SnO2. This work underscores the potential of the Co3O4-SnO2 heterojunction electrocatalyst as a cost-effective, durable anode catalyst for PEM electrolyzers.