In situ construction of hybrid Co(OH)2 nanowires for promoting long-term water splitting

Engineering the interfacial structure of hybrid catalysts is crucial for enhanced electrocatalytic performances. Herein, a new strongly heterogeneous catalyst of Co/CoO/Co(OH)(2) nanowires with proper interfacial structure was synthesized via a plasma etching approach. X-ray photoelectron spectroscopy and electron energy loss spectroscopy revealed that strong chemical couplings at the hybrid interface induced fast charge transfer, leading to considerable amounts of Co2+/Co sites present in the hybrid. The high conductivity from metal Co and one dimensional nanostructure favored the electron transfer and electrolyte access. The metallic Co was further oxidized to Co2+/Co3+ to address instability under applied potential during long-term testing. The resulting catalyst exhibited an excellent overpotential of 266 mV at 20 mA cm(-2) and a Tafel slope of 85 mV dec(-1) in alkaline medium. Importantly, the hybrid Co/CoO/Co(OH)(2) demonstrated a super long-term durability over 200 h among the most ultra-long stability Co-based OEC catalysts. This catalyst was applied on light absorbing BiVO4 for solar-driven water splitting, exhibiting a significantly enhanced photoelectrochemical (PEC) activity, 5.32 mA cm(-2) obtained at 1.23 VRHE, which represented one of the best performances achieved by Co-based OER cocatalysts.

Automated summary

Engineering the interfacial structure of Co/CoO/Co(OH)(2) nanowires via plasma etching approach led to fast charge transfer and high conductivity, resulting in enhanced electrocatalytic performances. The hybrid catalyst exhibited excellent stability and durability, showing promising potential for applications in solar-driven water splitting.