Plasma defect engineering to stabilize Mn-doped ruthenium dioxide nanoparticles for oxygen evolution via oxide path mechanism

Developing efficient acid-stable catalysts capable of driving the oxygen-evolution reaction (OER) via oxide-path mechanism (OPM) is of significant interest, but remains a considerable challenge. This work demonstrates that by employing an O 2 plasma treatment-assisted method, Mn-doped RuO 2 nanoparticles (NPs) supported on nitrogen-doped carbon nanotubes (p-RuMnO@NCNTs) can be developed to follow the OPM with superior OER activity and exceptional stability. The plasma treatment promotes the formation of more oxygen vacancies (Ov·) in p-RuMnO and enhances the crystallization of the p-RuMnO NPs. The p-RuMnO@NCNTs exhibits a low overpotential of only 123 mV to achieve 10 mA cm −2 , showing no significant activity loss over 200 h of continuous operation. Its Ru mass activity is 797 times higher than that of the commercial RuO 2 . Structure analysis indicates that the incorporation of Mn and the presence of more Ov· can create the dual-metal active sites with optimal atomic distances to facilitate the OER via the OPM. The DFT calculations indicate that the Mn incorporation, the presence of more Ov·, and the NCNTs support all contribute to the improved OER activity of the p-RuMnO@NCNTs. The p-RuMnO@NCNTs demonstrates great potential for practical applications in PEMWEs to achieve efficient and stable overall water splitting.