Coupling Dual-phased nickel selenides with N-doped carbon enables efficient urea electrocatalytic oxidation
2023
Cao, Qiuhan | Huang, Wen | Shou, Jiaru | Sun, Xiujuan | Wang, Kaili | Zhao, Yongjie | Ding, Rui | Lin, Weiwei | Liu, Enhui | Gao, Ping
Electrochemical urea oxidation reaction (UOR) is urgently in demand for diverse energy conversion and storage device coupled with pollution treatment because of its favorable thermodynamic potential (0.37 V vs RHE) and wide distribution nature of urea, but simultaneously gravely limited by the sluggish reaction dynamics and poisoning of catalyst. Herein, dual-phased Ni₀.₈₅Se/NiSe₂ coupling with N doped carbon (Ni₀.₈₅Se/NiSe₂@NC-2) in situ is prepared by a solvothermal-selenization pathway. Benefiting from the collective promotion of the dual-phased composition and the NC support, Ni₀.₈₅Se/NiSe₂@NC provides abundant active sites, enhanced electrical conductivity. It delivers a current density of 252 mA cm⁻² at 1.6 V vs RHE with a small Tafel slop of 64.4 mV dec⁻¹ and gets a lower reaction barrier. Moreover, it requires a cell voltage of 1.46 V to approach 50 mA cm⁻², about 250 mV less than that of water electrolysis, confirming the less energy consumption. Notably, the N doped carbon protects Ni₀.₈₅Se/NiSe₂ nanocrystals from aggregation leading to a faster CO₂ desorption from Ni sites, which endow the Ni₀.₈₅Se/NiSe₂@NC-2 a much better working stability. The direct urea hydrogen peroxide fuel cell (DUHPFC) achieves a maximum power density of 9.09 mW cm⁻² at 20 °C. This work extends highly efficient dual-phased structure loading in NC catalysts system for urea-assisted energy conversion.
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