Facile fabrication of flower-like CuS/MnCO3 microspheres clusters on nickel foam as an efficient bifunctional catalyst for overall water splitting |
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Authors: | Nannan Chen Yanhong Wang Xiaoqiang Du Xiaoshuang Zhang |
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Affiliation: | 1. School of Chemical Engineering and Technology, North University of China, Taiyuan, 030051, People''s Republic of China;2. School of Science, North University of China, Taiyuan, 030051, People''s Republic of China |
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Abstract: | Utilizing the abundant elements on earth to product inexpensive, high-active and stable catalysts for water splitting is very significant but still remains serious challenge to produce hydrogen. Herein, heterostructures of CuS/MnCO3 on nickel foam substrate are firstly successfully synthesized via a facile one-step hydrothermal strategy. The as-prepared electrocatalyst displays an enhanced oxygen evolution reaction (OER) performance in alkaline conditions with a minimum overpotential of 70 mV and a small Tafel slope of 42.5 mV/dec to achieve 10 mA cm?2. The catalyst also exhibits an excellent HER activity with a low overpotential of 143 mV and the Tafel slope of 51.4 mV/dec to acquire 10 mA cm?2 in 1.0 M KOH. Moreover, when the CuS/MnCO3//CuS/MnCO3 electrode is applied for the overall water splitting, the electrolyzer cell device affords 10 mA cm?2 at a relative low voltage of 1.43 V, which is one of the best catalysts ever reported. In stability test, its activity first decreases and then remains stable in 1 M KOH solution for about 10 h, indicating that the electrode has good electrochemical stability. Density functional theory calculations (DFT) show that MnCO3 has a stronger adsorption energy for water than CuS does, indicating that MnCO3 is a real active center and CuS plays a certain synergistic effect. This work not only provides a low-cost and efficient bifunctional catalyst for water splitting technology, but also extends the application of bifunctional catalyst based on transition metal sulfide and carbonate compound. |
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Keywords: | Density functional theory Water splitting Heterostructure Nickel foam |
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