Abstract
Rational synthesis of sub-nanocatalysts with controllable electronic and atomic structures remains a challenge to break the limits of traditional catalysts for superior performance. Here we report the atomic-level precise synthesis of Pt/graphene sub-nanocatalysts (from single atom, dimer, and to cluster) by atomic layer deposition, achieved by a novel high temperature pulsed ozone strategy to controllably pre-create abundant in-plane epoxy groups on graphene as anchoring sites. The specific in-plane epoxy structure endows the deposited Pt species with outstanding uniformity, controllability and stability. Their size-depended electronic and geometric effects have been observed for ammonia borane hydrolysis, revealing a volcano-type dependence of intrinsic activity on their sizes. Their active site structures have been identified based on extensive characterizations, dynamic compensation effect, kinetic isotope experiments and density function theory simulation. The Pt dimers show the highest catalytic activity and good durability than Pt single atoms and nanoparticles, ascribed to the unique C-Pt-Pt-O (C5Pt2O, metal-metal bond dimer) active site structure. Our work provides new insights into the precise tailoring and catalytic mechanism in sub-nanometer level.
Visualisation of single atom dynamics in water gas shift reaction for hydrogen generation
