Copper-Incorporated heterostructures of amorphous NiSex/Crystalline NiSe2 as an efficient electrocatalyst for overall water splitting

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2021-10, Vol.422, p.130048, Article 130048
• Main Authors: Park, Kyoung Ryeol, Tran, Duy Thanh, Nguyen, Thanh Tuan, Kim, Nam Hoon, Lee, Joong Hee
• Format: Article
• Language: English
• Subjects: Amorphous-crystalline heterostructures; Copper-nickel selenides; Core@shell nanostructures; Water splitting
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.130048

[Display omitted] •Novel Cu-implanted heterostructure of amorphous NiSex/crystalline NiSe2 is prepared.•Catalyst needs overpotential of 156.9 mV for HER and 339 mV for OER at 10 mA cm−2.•The catalyst-based electrolyzer requires a low cell voltage of 1.62 V at 10 mA cm−2.•The catalyst-based electrolyzer shows a long-term stability of 21.5 h in 1.0 M KOH. In this research, we designed a novel heterostructure of porous amorphous-crystalline nickel selenide incorporated with copper (Cu-(a-NiSex/c-NiSe2)) and shelled over one-dimensional TiO2 nanorods (NRs) to simultaneously accelerate both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics in alkaline environment. The Cu-(a-NiSex/c-NiSe2)/TiO2 NRs supported by carbon cloth displayed as an effective bifunctional catalyst, which required low overpotentials of 156.9 mV for HER and 339 mV for OER to achieve a current response of 10 mA cm−2 in 1.0 M KOH medium. An electrolyzer derived from the Cu-(a-NiSex/c-NiSe2)/TiO2 NRs material allowed an operation voltage of 1.62 V at 10 mA cm−2 along with good long-term stability after 21.5 h operation towards water splitting in alkaline medium. This achievement was resulted from the fine-tuned 3D porous architecture of the amorphous NiSex-crystalline NiSe2 heterostructures doped by copper, which led to significant modulation of electronic properties as well as large surface of exposed electroactive site/types, thereby effectively promoting the catalytic performance. This study suggested a rational approach of structure and shape engineering to design a potential catalyst for producing green hydrogen via water spitting.