Controllable tuning of polymetallic Co-Ni-Ru-S-Se ultrathin nanosheets to boost electrocatalytic oxygen evolution
Wei Deng, Wenshuo Xie, Dan Li, Yuping Gai, Zhide Chen, Jun Yu, Renqiang Yang, Xichang Bao, Fei Jiang
Abstract
Abstract Replacing precious metals in oxygen evolution reaction (OER) catalysts has broad prospects to achieve a viable water splitting system. Since the electrocatalytic OER is a four-electron transfer reaction with a very sluggish kinetic process, there is great interest in the development of inexpensive, durable, and high-efficiency OER catalysts. Herein, trimetallic Co-Ni-Ru sulfoselenide and bimetallic sulfoselenide nanosheets were designed by regulating their composition and morphology for efficient and durable OER electrocatalysis. The sheet structure has a large specific surface area to promote contact between the catalyst and electrolyte. Compared with bimetallic Co-Ni, Co-Ru, Ni-Ru, Co-Cd, and Co-Au sulfoselenide nanosheets, trimetallic Co-Ni-Ru sulfoselenide nanosheets show superior OER performance. By modulating the composition ratio of metal atoms in the Co-Ni-Ru-S-Se nanosheets (1:1:0.5:1:1), the nanosheets showed a significant OER overpotential of η = 261 mV (1.491 V versus RHE) at 10 mA cm −2 , a Tafel slope of 52.2 mV dec –1 and outstanding stability after 48 h of continuous testing. For comparison, Co-Ni, Co-Ru, Ni-Ru, Co-Cd, and Co-Au bimetallic sulfoselenide nanosheets (denoted as Co-Ni-S-Se, Co-Ru-S-Se, Ni-Ru-S-Se, Co-Au-S-Se, Co-Cd-S-Se) were also tested. Density functional theory (DFT) calculations showed that appropriately doping Ru and Ni simultaneously (Co-Ni-Ru-S-Se) can increase the density of the states at the Fermi level, resulting in excellent charge density and low intermediate adsorption energy. These findings present a practical route to design 2D polymetallic nanosheets to optimize catalytic OER performance.