Synergy Effect between Pt Single Atoms and Nanoclusters for Promoted Ammonia Borane Hydrolysis

Single-active-site catalytic materials, such as standalone single atoms (SAs) or nanoclusters/particles (NCs/NPs), generally face inherent trade-offs between atomic efficiency and performance. SAs offer high atomic utilization but sluggish kinetics, and NCs/NPs have high site density but poor atomic economy. Constructing SA/NC dual-site materials holds promise for overcoming these limitations. However, the dynamic synergistic interplay between these two components remains unclear. To gain insights into the synergistic behavior of dual-site materials, we herein carried out density functional theory calculations on Pt SA/NC dual sites, revealing regulated electronic states and enhanced reactant activation. The ammonia borane (AB) hydrolysis performance was investigated for a dual-site material synthesized via atomic layer deposition on TiO 2 nanosheets. It exhibits a turnover frequency of 1865.2 mol H2 mol Pt –1 min –1, 4.2 and 4.3 times higher than those of the SA-only and NC-only counterparts, respectively. Mechanistic studies reveal that the dual sites not only realize site-specific activation of H 2 O and AB but also collaboratively afford a successive proton-transfer channel mediated by bridging H 2 O, enabling rapid *H transfer for H 2 production. The universality of dual-site synergy is validated by extension to electrocatalytic methanol oxidation (MOR) and thermocatalytic p -chloronitrobenzene ( p -CNB) hydrogenation and is further complemented by evaluations on various supports and loaded elements, providing a rational basis for designing high-performance catalysts.