Plasma-modified Ni foam-supported CuCo2S4 nanowires as bifunctional electrocatalysts for high-performance overall water splitting

To solve the current energy and environmental dilemma, hydrogen energy is considered to be the best clean energy source to replace traditional fossil fuels. Water electrolysis as the main technology for hydrogen production has been affected by two half-reactions, making it difficult to improve the yield. To solve this problem, the development of inexpensive and efficient bifunctional electrocatalysts is the focus of current research. CuCo2S4/NF(Ni foam) nanowires are synthesized using a mild hydrothermal process and were later placed in a plasma reactor. Application of the voltage triggers a chemical reaction between the microdischarge wires and the sample. This leads to a change in the physical morphology of the catalyst and an improvement in its catalytic perfor-mance. The morphological characterization results show that the catalyst modification generates a distinct flower-like nanowire structure, which helps in the solid attachment of the catalyst to the nickel foam surface. The plasma-modified CuCo2S4/Ni foam (PA@CuCo2S4/NF) exhibits low overpotentials of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alka-line solutions. Additionally, the Tafel slopes of the HER and OER are 85.9 mVdec-1 and 142.7 mVdec-1, respectively, indicating optimal reaction kinetics. A cell voltage of only 1.55 V is required to provide a 10 mA cm -2 current during water splitting. This study validates the feasibility of using plasma technology to create high-performance electrocatalysts.(c) 2023 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

To address the current energy and environmental challenges, hydrogen energy is recognized as the most promising clean energy alternative to traditional fossil fuels. Water electrolysis, the main technology for hydrogen production, has been limited by two half-reactions, hampering yield improvement. To overcome this hurdle, the development of cost-effective and efficient bifunctional electrocatalysts has become a research focus. In this study, CuCo2S4/NF (Ni foam) nanowires were synthesized using a mild hydrothermal process and then subjected to a plasma reactor for modification. The plasma treatment led to a morphological change in the catalyst, resulting in a distinct flower-like nanowire structure that enhanced its catalytic performance. The plasma-modified CuCo2S4/Ni foam (PA@CuCo2S4/NF) exhibited low overpotentials for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in alkaline solutions. The Tafel slopes of the HER and OER were found to be 85.9 mVdec-1 and 142.7 mVdec-1, respectively, indicating favorable reaction kinetics. Furthermore, a cell voltage of only 1.55 V was sufficient to achieve a current density of 10 mA cm-2 during water splitting. This study demonstrates the feasibility of using plasma technology to create high-performance electrocatalysts.