Size hierarchy is a distinct feature of nanogold-catalysts as it can strongly affect their performance in various reactions. We developed a simple method to generate Au_nS_m nanoclusters of different sizes by thermal treatment of an Au₁₄₄(PET)₆₀ (PET: phenylethanethiol) parent cluster. These clusters, deposited on activated carbon, exhibit excellent catalytic performance in the hydrochlorination of acetylene. In-situ ultraviolet laser dissociation high-resolution mass spectrometry of the parent cluster in the presence of acetylene revealed a remarkable cluster size-dependence of acetylene adsorption, which is a crucial step in the hydrochlorination. Systematic density functional theory calculations of the reaction pathways on the differently-sized clusters provide deeper insight into the cluster size dependence of the adsorption energies of the reactants and afforded a scaling relationship between the adsorption energy of acetylene and the co-adsorption energies of the reactants (C₂H₂ and HCl), which could enable a qualitative prediction of the optimal Au_nS_m cluster for the hydrochlorination of acetylene.

The two-dimensional layered double hydroxides (LDHs) and zero-dimensional metal clusters have emerged as promising nanomaterials in the field of sustainable water oxidation, which can also facilitate joint experimental and computational studies. In this study, the synthesis of Ni₆@LDH composites, comprising atomically precise Ni₆(MPA)₁₂ (MPA: mercaptopropionic acid) clusters embedded into LDH nanosheets via electrostatic interaction, represents a significant advancement in the development of nanomaterials for sustainable water oxidation. Ni₆@NiFe-LDH exhibits superior electrochemical performance in oxygen evolution reaction (OER), exhibiting OER overpotentials of 198 mV@10 mA·cm⁻² and 290 mV@100 mA·cm⁻² with a low Tafel slope of 29 mV·dec⁻¹. It surpasses the corresponding NiFe-LDH and commercial RuO₂ catalysts, primarily due to the synergistic interaction between Ni₆ clusters and LDHs. Interestingly, our combined experimental and computational approach reveals that the M-OOH_ads formation is the rate-determining step (RDS) for the Ni₆-based catalysts, differing from the RDS for NiFe-LDH itself (the M-O_ads formation). These efforts serve as an attempt to push forward the current research frontier to study structure–property relationships progressing from the micro-/nano-level to the precise atomic-level.