Alkynyl and halogen co-protected (AuAg)44 nanoclusters: a comparative study on their optical absorbance, structure,
Yun Tang1, Fang Sun2, Xiaoshuang Ma1
1Guangzhou Key Laboratory for Surface Chemistry of Energy Materials, New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, Guangdong, 510006, P. R. China. zhht@scut.edu.cn.
Abstract:
We report the synthesis, structure, and electrochemical hydrogen evolution reaction (HER) performance of two alkynyl and halogen coprotected AuAg alloy nanoclusters, namely Au24Ag20(BuPh-CC)24Cl2 (NC 1 for short) and Au22Ag22(BuCC)16Br3.28Cl2.72 (NC 2 for short). Single crystal X-ray structural analysis revealed that the two nanoclusters possess a rather similar core@shell@shell keplerate metal core configuration to M12@M20@M12 with the main difference in the outermost shell (Au12vs. Au10Ag2). Interestingly, such a subtle difference in the two-metal-atoms results in different optical absorbance features and drastically different HER performances. Both NCs have excellent long-term stability for the HER, but NC 1 possesses superior activity to NC 2, and density functional theory calculations disclosed that the binding energy of hydrogen to form the key *H intermediate for NC 1 is much lower and hence it adopts a more energetically feasible HER pathway.
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