The exploration of high-performance, cost-effective, and stable electrocatalysts for the oxygen evolution reaction (OER) is crucial for future energy storage and conversion technologies. Cobalt-based hydroxides and oxides have been considered as ideal OER electrocatalysts and have been intensively studied; however, their catalytic activity is still unsatisfactory. It is known that the interfacial electron and structure engineering of composite electrocatalysts often results in synergistically enhanced catalytic performance. Herein, a self-supported binary heterogeneous catalyst composed of CoFe LDH/Co0.85Se nanosheet arrays vertically grown on carbon cloth has been reported. The heterostructure electrocatalyst exhibits excellent activity for the OER in alkaline electrolyte, requiring an overpotential of only 241 mV at a current density of 10 mA cm−2 with a small Tafel slope of 48 mV dec−1. These performances are significantly better than those of the bare CoFe LDH and Co0.85Se catalysts. Moreover, the composite electrodes exhibit outstanding durability within 40 h of testing. Our further electrochemical results show that the excellent activities of the heterostructure electrodes should be ascribed to the interfacial coupling effect, increased number of activity sites, accelerated electron transfer, and strong structural stability. This work paves an interesting route for boosting the OER performance of oxide-based electrocatalysts by the regulation of electronic structure through introducing non oxide electrocatalysts for various applications.
Junxiang Zhang,Zhuanpei Wang,Xuelian Li,Jie Yang,Chenhui Song,Yongpeng Li,Jianli Cheng,Qun Guan,Bin Wang
The fiber-shaped dye sensitized solar cell represents a promising flexible power conversion system for next generation wearable electronics due to its facile preparation, lightweight, and good weavability. However, the use of fiber-shaped dye sensitized solar cells is largely limited by their low power conversion efficiency and flexibility. Herein, a flexible Pt-free fiber-shaped dye sensitized solar cell with a high power conversion efficiency of 10.28% is fabricated, by sequentially growing polyaniline layers and Co0.85Se nanosheets on the surface of carbon fibers as the counter electrodes and TiO2 nanotubes grown on the Ti wire as the photoanode. The polyaniline layer can not only work as the nucleation sites for the following deposition of the Co0.85Se nanosheets but also act as the catalytic sites with large specific surface area to further improve the catalytic activity and reduce the charge transfer resistance, while the Co0.85Se nanosheets can further improve the electrocatalytic activity for the transition of I–/I3–, leading to a remarkably enhanced photovoltaic performance of the cell. This result provides a new design strategy for high-performance flexible fiber-shaped dye sensitized solar cells.
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