Anion insertion enhanced electrodeposition of robust metal hydroxide/oxide electrodes for oxygen evolution

Abstract

Electrochemical deposition is a facile strategy to prepare functional materials but suffers from limitation in thin films and uncontrollable interface engineering. Here we report a universal electrosynthesis of metal hydroxides/oxides on varied substrates via reduction of oxyacid anions. On graphitic substrates, we find that the insertion of nitrate ion in graphene layers significantly enhances the electrodeposit–support interface, resulting in high mass loading and super hydrophilic/aerophobic properties. For the electrocatalytic oxygen evolution reaction, the nanocrystalline cerium dioxide and amorphous nickel hydroxide co-electrodeposited on graphite exhibits low overpotential (177 mV@10 mA cm ⁻²) and sustains long-term durability (over 300 h) at a large current density of 1000 mA cm ⁻². In situ Raman and operando X-ray diffraction unravel that the integration of cerium promotes the formation of electrocatalytically active gamma-phase nickel oxyhydroxide with exposed (003) facets. Therefore, combining anion intercalation with cathodic electrodeposition allows building robust electrodes with high electrochemical performance.

Abstract

Electrodeposition provides a facile fabrication means for electrochemical devices but weak substrate-deposit interactions cause poor performance. Here, authors utilize anion insertion within graphitic layers to improve the material interfaces and construct highly active O ₂-evolving electrocatalysts.