Hydrogen, which possesses high gravimetric energy density, has recently received great attentions to respond to the seriousness of global climate change [1, 2]. In particular, the alkaline water electrolysis cells (AECs) that can produce hydrogen through electrochemical reactions without greenhouse gas emissions are substantially promising as renewable next-generation energy storage and conversion devices. In AECs, oxygen evolution reactions (OERs) occur at the anode, while hydrogen evolution reactions take place at the cathode [3, 4]. However, the sluggish kinetics of the multi-electron transfer process is a paramount challenge for efficient OER activity. Furthermore, precious metal catalysts such as iridium and ruthenium are still mainly used as an OER catalyst, and their low economic efficiency and durability are acting as major problems in the commercialization stage. Therefore, the reduction of reaction overpotential is crucial to boost catalytic efficiency for OER in AECs. In this study, the OER catalyst study is performed on sulfide-based chalcogenide materials. It has been reported that the sulfide-based chalcogenide materials have shown the excellent catalytic activity because the covalent characteristics between transition metal and chalcogenide is stronger than that of oxide-based catalysts [5]. In particular, among various sulfide-based chalcogenide materials, nickel sulfide-based catalysts have actively studied because they can simply synthesize using a hydrothermal method. Additionally, nickel sulfides have a structurally Ni-Ni metal bond that makes it easy to transfer charge species for OERs. Herein, various transition metals are doped into the nickel sulfide to improve the catalytic activity and electrical conductivity via generation of extra defects in the crystal structure. The crystal structure and catalytic activity of chalcogenide catalysts are analyzed through various physicochemical and electrochemical analysis methods.

References

[1] Hainan Sun, Xiaomin Xu, Zhiwei Hu, Liu Hao Tjeng, Jie Zhao, Qin Zhang, Hong-Ji Lin, Chien-Te Chen, Ting-Shan Chan, Wei Zhou, Zongping Shao, Journal of Materials Chemistry A 7 (2019) 9924.

[2] Thomas E. Mallouk, Nature Chemistry 5 (2013) 362–363.

[3] Muhammad Saqib, In-Gyu Choi, Hohan Bae, Kwangho Park, Ji-sup Shin, You-Dong Kim, John-In Lee, Minkyeong Jo, Yeong-Cehol Kim, Kug-Seung Lee, Sun-Ku Song, Eric D. Wachsman and Jun-Young Park, Energy & Environmental Science 14 (2021) 2472–2484.

[4] Sung Ryul Choi, John-In Lee, Hyunyoung Park, Sung Won Lee, Dong Yeong Kim, Won Young An, Jung Hyun Kim, Jongsoon Kim, Hyun-seok Cho, Jun-Young Park, Chemical Engineering Journal 409 (2021) 128226.

[5] Hatem M. A. Amin, UIf-Peter Apfel, European Journal of Inorganic Chemistry 2020 (2020) 2679–2690.

Keywords: Oxygen evolution reaction, Alkaline electrolysis cell, Water splitting, Transition metal, Post-transition metal, Chalcogenide.

* Corresponding author: jyoung@sejong.ac.kr (J. Y. Park)