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Updated: Aug 8, 2025
A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles
Published on: April 10, 2019
Direct Observation of Transition Metal Ions Evolving into Single Atoms: Formation and Transformation of Nanoparticle
Zheng Han1, Yi Wang1, Jiming Zheng1
1State Key Laboratory of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon-Technology, Northwest University, Xi'an, 710069, P. R. China.
Abstract:
Understanding the dynamical evolution from metal ions to single atoms is of great importance to the rational development of synthesis strategies for single atom catalysts (SACs) against metal sintering during pyrolysis. Herein, an in situ observation is disclosed that the formation of SACs is ascertained as a two-step process. There is initially metal sintering into nanoparticles (NPs) (500-600 °C), followed by the conversion of NPs into metal single atoms (Fe, Co, Ni, Cu SAs) at higher temperature (700-800 °C). Theoretical calculations together with control experiments based on Cu unveil that the ion-to-NP conversion can arise from the carbon reduction, and NP-to-SA conversion being steered by generating more thermodynamically stable Cu-N4 configuration instead of Cu NPs. Based on the evidenced mechanism, a two-step pyrolysis strategy to access Cu SACs is developed, which exhibits excellent ORR performance.
