This recently conducted study was led by Professor Zhong-Qun Tian (University of Xiamen) and Professor Kostya S. Novoselov (National University of Singapore).
Having been sourced from its ultrafast laser-to-thermal conversion capacity and graphene’s impenetrable and adaptable features, Dr. Ye-Chuang Han (lead author) and Professor Zhong-Qun Tian discovered the concept and selected graphene as the available diffusion-limited nanoreactor for high-temperature reactions.
In one pulse of nanosecond laser irradiation, they found that the graphene irradiated area acquires a very high heating or cooling rate of 109 °C/s, and refers to the heating technique as graphene-limited ultrafast radiant heating (GCUH).
In addition, through a partnership with Dr. Jun Yi (first co-author) and Professor Kostya S. Novoselov, researchers carried out theoretical calculations and found that the very fast cooling process is in line with the Stefan-Boltzmann law, and it turns out that radiation is the main mode of energy release at very high temperatures.
Thermally activated ultrafast diffusion, collision, and combination of metal atoms are the basic processes for synthesizing the developing subnanometer metal clusters, and no technique exists that enables the kinetically controllable synthesis of subnanometer metal clusters without compromising metal loading.
Dr. Ye-Chuang Han and Dr. Beibei Pang (first co-author, University of Science and Technology of China) illustrated that the kinetics-driven GCURH method has the potential to synthesize subnanometer Co cluster catalysts with high metal loads of up to 27.1 wt%.
This can be accomplished by pyrolyzing Co-based metal-organic frameworks in only microseconds, thus being one of the largest size loading and fastest rate combinations for MOF pyrolysis in the reported literature.
Overall, this work offers a general plan for beating the trade-off prize between ultra-small size and high charge in metal cluster catalysts. Also, it carries great promise for the upcoming industrial applications of cluster catalysts.
Han, YC., et al. (2023) Ultrafast radiant heating constrained graphene for high load subnanometer metal cluster catalysts. National Science Review. doi.org/10.1093/nsr/nwad081.