Binary ruthenium dioxide and nickel oxide ultrafine particles loaded on carbon nanotubes for high-stability oxygen evolution reaction at high current densities.

RuO ₂ is an efficient electrocatalyst for the oxygen evolution reaction (OER). However, during the OER process, RuO ₂ is prone to oxidation into Ru ^x+ (x > 4), leading to its dissolution in the electrolyte and resulting in poor stability of RuO ₂ . Here, we report a bicomponent electrocatalyst, NiO and RuO ₂ co-loaded on carbon nanotubes (RuO ₂ /NiO/CNT). The results demonstrate that the introduction of NiO suppresses the over-oxidation of RuO ₂ during the OER process, not only inheriting the excellent catalytic performance of RuO ₂ , but also significantly enhancing the stability of the catalyst for OER at high current densities. In contrast to RuO ₂ /CNT, RuO ₂ /NiO/CNT shows no significant change in activity after 150 h of OER at a current density of 100 mA cm ^-2 . Density functional theory (DFT) calculations indicate that NiO transfers a large number of electrons to RuO ₂ , thereby reducing the oxidation state of Ru. In conclusion, this study provides a detailed analysis of the phenomenon where low-valent metal oxides have the ability to enhance the stability of RuO ₂ catalysts.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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