Laser-driven solid-state route to ultrasmall nanocatalysts Dr. Huize Wang 1,2 , Prof. Marc Ledendecker 1,2 1 Technical University of Munich, Campus Straubing, Schulgasse 22, 94315 Straubing, Germany, 2 Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Cauerstraße 1, 91058 Erlangen, Germany Electrochemical processes such as electrolysis, fuel cell oxygen reduction, CO 2 conversion, and ammonia synthesis are central to decarbonization efforts. 1 Yet, practical applications face challenges beyond catalyst activity and stability, including the need for sustainable and scalable synthesis methods. In proton exchange membrane electrolysis (PEMWE), developing stable and active catalysts remains challenging due to the harsh oxygen evolution reactions (OER) environment. Iridium oxide is among the most stable options. However, its low activity and iridium scarcity require strategies to enhance atomic utilization. To address these challenges, alternative synthesis methods that enable precise control over catalyst structure and composition are highly desirable. Laser-induced synthesis has recently gained attention as a practical method for preparing nanostructured catalysts and has also shown potential in sustainable ammonia production. 2,3 Compared to liquid-phase irradiation, solvent-free solid-phase processing has the potential to be faster, more economical, and more scalable. 3,4 Here, we present a novel laser-induced synthesis approach for fabricating ultra-small metal or metal oxide nanoparticles in the solid phase, as opposed to conventional liquid-phase methods, as illustrated in Figure 1A. 5 Upon laser irradiation, the iridium precursor rapidly transforms into ultra-small crystalline IrO 2 and Ir particles, approximately 2 nm and 1 nm in diameter, respectively as illustrated in Figure 1B. The laser-induced synthesis of IrO 2 resulted in a catalyst with an exceptionally high mass activity of 350 ± 15 A g Ir -¹ at 300 mV overpotential, surpassing the activity of state-of-the-art iridium oxide (Alpha Aesar) materials (Figure 1C) by a factor of 5 and outperforming all previously reported IrO 2 catalysts synthesized via conventional methods. This laser-induced solid-state synthesis method enables the development of stable and efficient corrosion- resistant iridium-based catalysts for acidic OER, while also showing strong potential for synthesizing ultrasmall mixed-metal and mixed-metal oxide nanoparticles. Moreover, the approach is compatible with the fabrication of atomic-scale catalysts, which can maximize metal utilization—particularly for noble metals—and facilitate the design of highly active, selective, and scalable electrocatalysts for a broad range of electrochemical energy conversion processes.
Figure 1: A) Schematic diagram of the synthesis process: first, the iridium hydroxide precursor is irradiated to obtain crystalline rutile IrO2. B) The dark-field STEM images of IrO 2 nanoparticles encapsulated in silica. C) Mass normalized activities of laser- induced synthesized (Lis)-IrO 2 , Ir and comparing the state-of-the-art commercial IrO 2 5 References 1. Cabana, J. et al. NGenE 2022: Electrochemistry for Decarbonization. ACS Energy Lett. 8, 740–747 (2023). 2. Wang, B. et al. General synthesis of high-entropy alloy and ceramic nanoparticles in nanoseconds. Nat. Synth. 1, 138–146 (2022). 3. Wang, H. et al. Laser-induced nitrogen fixation. Nat. Commun. 14, 5668 (2023). 4. Kumar, A. et al. Solid-State Reaction Synthesis of Nanoscale Materials: Strategies and Applications. Chem. Rev. 122, 12748–12863 (2022). 5. Wang, H. et al. Laser-Engineered Iridium-Based Nanoparticles with High Activity and Stability. at https://doi.org/10.26434/ chemrxiv-2025-nr4f2 (2025).
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© The Author(s), 2025
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