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

• Published in: Applied catalysis. B, Environmental Environmental, 2021-09, Vol.292, p.120063, Article 120063
• Main Authors: Liu, Shujie, Gao, Rui-Ting, Sun, Mao, Wang, Yan, Nakajima, Tomohiko, Liu, Xianhu, Zhang, Wei, Wang, Lei
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Catalysts; Charge transfer; Cobalt; Couplings; Durability; Electromagnetic absorption; Electron energy loss spectroscopy; Electron transfer; Energy dissipation; Energy loss; Etching; Hybrid Co(OH)2 oxygen evolution catalyst; Long-term durability; Nanotechnology; Nanowires; Photoelectron spectroscopy; Photoelectrons; Plasma etching; Solar water splitting; Spectroscopy; Spectrum analysis; Water splitting
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120063

[Display omitted] •Engineering the interfacial structure of hybrid catalysts for enhanced electrocatalytic performances.•A heterogeneous Co/CoO/Co(OH)2 robust nanowires with high conductivity.•The Co was oxidized to Co2+/Co3+ under potential with a super durability over 200 h.•A high photocurrent of 5.32 mA cm−2 at 1.23 VRHE and durability are obtained for Co/CoO/Co(OH)2/BiVO4. 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.