In Situ Electrochemical Oxidation of Cu₂S into CuO Nanowires as a Durable and Efficient Electrocatalyst for Oxygen Evolution Reaction

Abstract

The development of cost-effective oxygen evolution catalysts is of capital importance for the deployment of large scale energy storage systems based on metal-air batteries and reversible fuel cells. In this direction, a wide range of materials have been explored, especially in more favorable alkaline conditions, and several metal chalcogenides have particularly demonstrated excellent performances. However, chalcogenides are thermodynamically less stable than the corresponding oxides and hydroxides under oxidizing potentials in alkaline media. While this instability in some cases has prevented the application of chalcogenides as oxygen evolution catalysts, and it has been disregarded in some other, we propose to use it in our favor to produce high performance oxygen evolution catalysts. We characterize here the in situ chemical, structural and morphological transformation during the oxygen evolution reaction (OER) in alkaline media of Cu2S into CuO nanowires (NWs), mediating the intermediate formation of Cu(OH)2. We also test their OER activity and stability under OER operation in alkaline media, and compare them with the OER performance of Cu(OH)2 and CuO nanostructures directly grown on the surface of a copper mesh. We demonstrate here that CuO produced during OER from Cu 2 S displays an extraordinary electrocatalytic performance toward OER, well above that of CuO and Cu(OH)2 synthesized mediating no OER in situ transformation.3

Superior methanol electrooxidation performance of (110)-faceted nickel polyhedral nanocrystals

“…This result is consistent our previous work on the in situ oxidation of copper chalcogenides to CuO during OER. 45 Finally, electrodes based on polyhedral and spherical Ni NCs were analyzed by EIS in open circuit condition within a solution containing 1.0 M KOH and 1.0 M methanol at 0.6 V vs. Hg/HgO ( Figure S14). Data was precisely fitted using the model circuit shown in figure S14.…”

Understanding Surface Recombination Processes Using Intensity‐Modulated Photovoltage Spectroscopy on Hematite Photoanodes for Solar Water Splitting

“…Despite considerable efforts to boost the solar‐to‐hydrogen (STH) conversion efficiency for unassisted solar water splitting, the performance and stability of PEC tandem cell device is still insufficient for commercialization . The major performance bottleneck for these devices is attributed to photoanode where the sluggish water oxidation reaction occurs . Thus significant efforts have been dedicated to understanding and improving the performance of photoanode materials.…”

Zinc Substitution‐Induced Subtle Lattice Distortion Mediates the Active Center of Cobalt Diselenide Electrocatalysts for Enhanced Oxygen Evolution

“…Subsequently, the nature of active species on the surfaces was explored by characterization of the electrodes after OER. It has been reported that the active sites of metal‐based catalysts under alkaline conditions for OER are located in a thin layer of oxide/hydroxide on the surface 40–43. The detection of slight metal ion in the electrolytes after electrochemical measurements suggests the surface reconstruction of the Zn‐CoSe 2 NAs (Figure S12, Supporting Information).…”

“…It has been reported that the active sites of metal-based catalysts under alkaline conditions for OER are located in a thin layer of oxide/hydroxide on the surface. [40][41][42][43] The detection of slight metal ion in the electrolytes after electrochemical measurements suggests the surface reconstruction of the Zn-CoSe 2 NAs ( Figure S12, Supporting Information). Further proof could be revealed by the CV curve images of the Zn-CoSe 2 NAs (Figure 4a).…”