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Uncovering near-free platinum single-atom dynamics during electrochemical hydrogen evolution reaction.

Shi FangXiaorong ZhuXiaokang LiuJian GuWei LiuDanhao WangWei ZhangYue LinJunling LuShiqiang WeiYafei LiTao Yao
Published in: Nature communications (2020)
Single-atom catalysts offering intriguing activity and selectivity are subject of intense investigation. Understanding the nature of single-atom active site and its dynamics under working state are crucial to improving their catalytic performances. Here, we identify at atomic level a general evolution of single atom into a near-free state under electrocatalytic hydrogen evolution condition, via operando synchrotron X-ray absorption spectroscopy. We uncover that the single Pt atom tends to dynamically release from the nitrogen-carbon substrate, with the geometric structure less coordinated to support and electronic property closer to zero valence, during the reaction. Theoretical simulations support that the Pt sites with weakened Pt-support interaction and more 5d density are the real active centers. The single-atom Pt catalyst exhibits very high hydrogen evolution activity with only 19 mV overpotential in 0.5 M H2SO4 and 46 mV in 1.0 M NaOH at 10 mA cm-2, and long-term durability in wide-pH electrolytes.
Keyphrases
  • molecular dynamics
  • electron transfer
  • high resolution
  • ionic liquid
  • gold nanoparticles
  • mass spectrometry
  • room temperature