Enhancing Metal-Support Interactions of Ru Catalysts via Relaxation of Oxygen Vacancies for Hydrogen Production

Abstract

The stability of Ru-based catalysts under harsh electrochemical conditions is a critical challenge limiting their practical application in energy conversion systems. In this study, Ru catalysts supported on ZrO2-x, CeO2-x, and ZrCeO2-x are synthesized via pyrolysis of metal-organic frameworks (MOFs) and systematically evaluated to elucidate the role of support interactions on catalytic performance and durability. Advanced characterization techniques, including HR-TEM, XRD, XPS, and EXAFS, revealed that Ru-ZrCeO2-x exhibited superior structural stability compared to Ru-ZrO2-x and Ru-CeO2-x, particularly under high-potential sweep (HPS) conditions. The incorporation of Ce into ZrO2-x is shown to stabilize oxygen vacancies and enhance the interaction between Ru catalyst and the support, thereby mitigating catalyst degradation. Density functional theory (DFT) calculations further confirmed that Ce doping decreases formation energy of the oxygen vacancy, providing a thermodynamically favorable environment for Ru stabilization. This work demonstrates the promise of ZrCeO2-x as a robust support material for Ru-based catalysts, advancing their potential for durable and efficient energy applications.