Recently, Professor Zhuhua Zhang/ Academician Wanlin Guo'team from institute for Frontier Sciences (hereinafter referred to as IFS) , Professor Yongmin He from the School of Chemistry and Chemical Engineering of Hunan University, and Professor Zheng Liu from Nanyang Technological University, Singapore cooperated with the team to conduct accurate first-principles calculations and experiments. In combination, a single-atom-layer noble metal catalyst was designed. The research result was published online in Nature Catalysis under the title of Amorphizing noble metal chalcogenide catalysts at the single-layer limit towards hydrogen production and was selected for the cover of the March magazine.
Rational design of noble metal catalysts and improved utilization are critical for industrial applications. Currently, noble metal catalysts with high activity and selectivity (such as platinum, palladium, etc.) are often used in water electrolysis for hydrogen production, fuel cells and air batteries and other energy fields. However, the scarcity of the earth's reserves (for example, the content of platinum in the crust is only five parts per billion) and the high cost (for example, platinum 200-250 yuan/g) hinder the large-scale application of precious metal catalysts. Taking the automotive market as an example, in order to meet the cost control needs of fuel cell systems, the Pt content in batteries has been reduced from 0.117 g/kWgross in 2018 to 0.108 g/kWgross in 2020, and is expected to drop to 0.064 g/kWgross in 2025 kWgross. Therefore, how to improve the utilization rate of precious metals is the main direction of current research. Nanoization of precious metals is an effective general strategy to improve their utilization and reduce weight loading. At present, a variety of noble metal nanostructures have been reported, ranging from large three-dimensional porous structures, two-dimensional nanosheet structures, one-dimensional nanowires, to small zero-dimensional nanoclusters and even single atoms. catalyst. Following this trend, the utilization of precious metals will eventually evolve into single-atom-layer catalysis. That is, almost all noble metal atoms may participate in the reaction as active sites.
In order to realize single atomic layer catalysis, the research team used the atomic layer structure characteristics of the two-dimensional material itself, and pre-simulated the structural characteristics and structural stability of amorphized PtSex through first-principles calculations, and predicted amorphization through theoretical calculations. The zero boundary point of the transition is pointed out, and the excellent catalytic properties that the material in the amorphous state may possess. Subsequently, a low-temperature amorphization strategy was used experimentally to fabricate wafer-sized amorphous PtSex films on SiO2 substrates, which enabled a high atomic utilization rate (~26 wt%) of single-atom-layer platinum. This amorphous PtSex (1.2 < x < 1.3) has a fully activated amorphous surface that readily catalyzes reactions, has a current density close to 100% relative to pure platinum surfaces, and enables reliable and continuous hydrogen production on 2-inch wafers . In addition, the electrolyzer with this PtSex electrode can generate a high current density of 1000 mA cm−2. This amorphization strategy can also be extended to other noble metals, including Pd, Ir, Os, Rh, and Ru elements, demonstrating the universality of single-atom-layer catalysis.
This research is expected to expand the design of current catalyst systems and reduce the application cost of noble metal catalysts. The paper was published in the internationally recognized top journal Nature Catalysis in the field of catalysis. Professor Zhuhua Zhang from IFS is the corresponding author, postdoctoral fellow Liren Liu (now associate professor of Nanjing University of Technology) is the co-first author, and the co-authors also include Zhiqiang Zhao, and Academician Wanlin Guo.
Link: https://doi.org/10.1038/s41929-022-00753-y
