Co<sub>3</sub> O<sub>4</sub> /Fe<sub>0.33</sub> Co<sub>0.66</sub> P Interface Nanowire for Enhancing Water Oxidation Catalysis at High Current Density.

Zhang, Xiaoyan; Li, Jing; Yang, Yong; Zhang, Shan; Zhu, Haishuang; Zhu, Xiaoqing; Xing, Huanhuan; Zhang, Yelong et al. · Adv Mater · 2018

basic_science · Level V

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Abstract

Designing well-defined nanointerfaces is of prime importance to enhance the activity of nanoelectrocatalysts for different catalytic reactions. However, studies on non-noble-metal-interface electrocatalysts with extremely high activity and superior stability at high current density still remains a great challenge. Herein, a class of Co<sub>3</sub> O<sub>4</sub> /Fe<sub>0.33</sub> Co<sub>0.66</sub> P interface nanowires is rationally designed for boosting oxygen evolution reaction (OER) catalysis at high current density by partial chemical etching of Co(CO<sub>3</sub> )<sub>0.5</sub> (OH)·0.11H<sub>2</sub> O (Co-CHH) nanowires with Fe(CN)<sub>6</sub> <sup>3-</sup> , followed by low-temperature phosphorization treatment. The resulting Co<sub>3</sub> O<sub>4</sub> /Fe<sub>0.33</sub> Co<sub>0.66</sub> P interface nanowires exhibit very high OER catalytic performance with an overpotential of only 215 mV at a current density of 50 mA cm<sup>-2</sup> and a Tafel slope of 59.8 mV dec<sup>-1</sup> in 1.0 m KOH. In particular, Co<sub>3</sub> O<sub>4</sub> /Fe<sub>0.33</sub> Co<sub>0.66</sub> P exhibits an obvious advantage in enhancing oxygen evolution at high current density by showing an overpotential of merely 291 mV at 800 mA cm<sup>-2</sup> , much lower than that of RuO<sub>2</sub> (446 mV). Co<sub>3</sub> O<sub>4</sub> /Fe<sub>0.33</sub> Co<sub>0.66</sub> P is remarkably stable for the OER with negligible current loss under overpotentials of 200 and 240 mV for 150 h. Theoretical calculations reveal that Co<sub>3</sub> O<sub>4</sub> /Fe<sub>0.33</sub> Co<sub>0.66</sub> P is more favorable for the OER since the electrochemical catalytic oxygen evolution barrier is optimally lowered by the active Co- and O-sites from the Co<sub>3</sub> O<sub>4</sub> /Fe<sub>0.33</sub> Co<sub>0.66</sub> P interface.