Heterointerface-driven integration of energy storage and hydrogen evolution in a Co(OH)2@BiOI@g-CN ternary hybrid

초록

The advancement of hybrid electrode materials with multiple functions is motivated by the growing need for superior energy storage and conversion technologies. Herein, a rationally designed cobalt hydroxide/bismuth oxyiodide@graphitic carbon nitride (Co(OH)2@BiOI@g-CN) ternary hybrid serves as a viable supercapacitor (SC) electrode material and is further evaluated for the hydrogen evolution reaction (HER). The synergistic effect of the pseudocapacitive Co(OH)2, semiconductive BiOI, and conductive g-CN ensures the efficiency of charge storage, electron transfer, and structural stability. The Co(OH)2@BiOI@g-CN composite demonstrates a superior specific capacitance of 3301.6 +/- 90 F/g at 1 A/g in a three-electrode system. Additionally, the asymmetric device demonstrates a specific capacity of 197.7 +/- 20 C/g at 1 A/g, along with an energy density of 45 Wh/kg and a power density of 2915 W/kg, and retains 91% capacitance over 10,000 cycles at 2 A/g. The ternary composite demonstrates improved kinetic activity for the HER reaction, with a low Tafel slope of 70 mV/dec, confirming its potential as a multifunctional material.

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