Construction of Pd-doped RuO2 nanosheets for efficient and stable acidic water oxidation

RuO₂ has been considered a potential alternative to commercial IrO₂ for the oxygen evolution reaction (OER) due to its superior intrinsic activity. However, its inherent structure dissolution in acidic environments restricts its commercial applications. In this study, we report a novel Pd-doped ruthenium oxide (Pd-RuO₂) nanosheet catalyst that exhibits improved activity and stability through a synergistic effect of Pd modulation of Ru electronic structure and the two-dimensional structure. The catalyst exhibits excellent performance, achieving an overpotential of only 204 mV at a current density of 10 mA cm^-2. Impressively, after undergoing 8000 cycles of cyclic voltammetry testing, the overpotential merely decreased by 5 mV. The PEM electrolyzer with Pd_0.08Ru_0.92O₂ as an anode catalyst survived an almost 130 h operation at 200 mA cm^-2. To elucidate the underlying mechanisms responsible for the enhanced stability, we conducted an X-ray photoelectron spectroscopy (XPS) analysis, which reveals that the electron transfer from Pd to Ru effectively circumvents the over-oxidation of Ru, thus playing a crucial role in enhancing the catalyst's stability. Furthermore, density functional theory (DFT) calculations provide compelling evidence that the introduction of Pd into RuO₂ effectively modulates electron correlations and facilitates the electron transfer from Pd to Ru, thereby preventing the over-oxidation of Ru. Additionally, the application of the two-dimensional structure effectively inhibited the aggregation and growth of nanoparticles, further bolstering the structural integrity of the catalyst.