Mottakin M, Selvanathan Vidhya, Ariful Islam Md, Almohamadi Hamad, Alharthi Nabeel H, Yoshimura Satoru, Akhtaruzzaman Md
Solar Energy Research Institute (SERI, Universiti Kebangsaan Malaysia (UKM) (@ The National University of Malaysia), Bangi, 43600, Selangor, Malaysia.
Dept. of Applied Chemistry and Chemical Engineering, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, 8100, Bangladesh.
Chem Asian J. 2024 Aug 19;19(16):e202300532. doi: 10.1002/asia.202300532. Epub 2023 Aug 18.
This study explores a water-splitting activity using a biphasic electrodeposited electrode on nickel foam (NF). The *NiS/CuS/NF electrode with citric acid reduction exhibits superior OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) performance with reduced overpotential and a steeper Tafel slope. The *NiS/CuS/NF electrode displays the ultra-low overpotential value of 212 mV for OER and 109 mV for HER at the current density of 10 mA cm. The Tafel slope of 25.4 mV dec for OER and 108 mV dec for HER was found from that electrode. The maximum electrochemical surface area (ECSA), lowest series resistance and lowest charge transfer resistance are found in citric acid reduced electrode, showing increased electrical conductivity and quick charge transfer kinetics. Remarkably, the *NiS/CuS/NF electrode demonstrated excellent stability for 80 hours in pure water splitting and 20 hours in seawater splitting. The synergistic effect of using bimetallic (Cu&Ni) sulfide and enhanced electrical conductivity of the electrode are caused by reduction of metal sulfide into metallic species resulting in improved water splitting performance.
本研究探索了使用在泡沫镍（NF）上双相电沉积电极的析氢活性。经柠檬酸还原的NiS/CuS/NF电极展现出卓越的析氧反应（OER）和析氢反应（HER）性能，过电位降低且塔菲尔斜率更陡。在10 mA cm的电流密度下，NiS/CuS/NF电极的析氧过电位超低，为212 mV，析氢过电位为109 mV。从该电极测得析氧反应的塔菲尔斜率为25.4 mV dec，析氢反应的塔菲尔斜率为108 mV dec。在经柠檬酸还原的电极中发现了最大的电化学表面积（ECSA）、最低的串联电阻和最低的电荷转移电阻，表明其电导率增加且电荷转移动力学加快。值得注意的是，NiS/CuS/NF电极在纯水分解中表现出80小时的优异稳定性，在海水分解中表现出20小时的优异稳定性。使用双金属（Cu&Ni）硫化物的协同效应以及电极电导率的提高是由于金属硫化物还原为金属物种，从而改善了析氢性能。
