Researchers from the UK and China have reported a novel technique for accelerating the development of binary metal oxide nanoarchitecture and layered double hydroxides on nickel foams for electrocatalytic applications. This technique is based on a laser-induced hydrothermal reaction (LIHR) mechanism and is detailed in a study published in the International Journal of Extreme Manufacturing on November 1st, 2023.
Laser-induced hydrothermal growth (LIHG) can occur in the ambient atmosphere to prepare integrated electrodes with dense nanosheet arrays on nickel foams for electrocatalysis (with or without further treatment). Image Credit: Yang Sha, Menghui Zhu, Kun Huang, Yang Zhang, Francis Moissinac, Zhizhou Zhang, Dongxu Cheng, Paul Mativenga and Zhu Liu.
Developing electrocatalysts to break through the kinetic energy barriers for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is necessary for the large-scale electrochemical synthesis of hydrogen from water splitting. Low-cost, stable, and active electrocatalysts are required.
While there are many options, non-precious nickel-based catalysts—Ni-Mo catalysts in particular—have become well-known for alkaline HER, while layered-double hydroxides (LDHs) based on transition metals—Fe, Co, and Ni—have acquired popularity for OER catalysts in alkaline media.
However, those electrocatalysts are often made by solvothermal or hydrothermal processes, which take a lot of energy and time in addition to autoclaves and solvents.
To overcome these issues, the team that pioneered laser electrocatalyst synthesis expanded on an alternate way to conventional hydrothermal treatment by laser irradiating a substrate immersed in a liquid containing metal salt precursors.
The hydrothermal reaction mechanism occurs on nickel foams when the laser beam interaction at the interface between the liquid (containing Ni/Mo or Fe/Ni precursors) and nickel substrate produces a combination of high temperature and high pressure, which fulfills the requirement of metal oxide growth on the substrate.
Such nanostructures produced by the LIHR exhibit excellent catalytical activity for overall water splitting, and more importantly, with a superior durability under an industrial current density, to the majority of reported catalysts, and commercial precious metal catalysts. In addition, the LIHG improves the production rate by over 19 times, but only consumes 27.78% of the total energy required by conventional hydrothermal methods to achieve the same production.
Dr. Yang Sha, Study First Author and PhD Student, The University of Manchester
Professor Zhu Liu, from the Chinese Academy of Science, Ningbo Institute of Material Technology and Engineering, added, “LIHR was first reported in 2013 by Yeo et al. to produce local ZnO nanowires through photothermal reactions. This technique is rapid, versatile, scalable and cost-effective, enabling direct synthesis of metal oxide nanostructures. However, this technique has been well understudied and its potential applications have yet to be explored. We hope this study offers a new route for the rapid synthesis of free-standing electrocatalytic electrodes. We continue to extend its applications including the LIHR growth of nanostructured metal oxide (ZnO, SnO2) thin-films for perovskite solar cells.”
Journal Reference:
Sha, Y., et. al. (2023) Towards a new avenue for rapid synthesis of electrocatalytic electrodes via laser-induced hydrothermal reaction for water splitting. International Journal of Extreme Manufacturing. doi:10.1088/2631-7990/ad038f