Precisely constructed diatomic metal sites that bridge the gap between single-atom dispersion and cluster-like synergy offer a promising strategy to overcome the activity-selectivity trade-off in heterogeneous catalysis. In this work, we report the synthesis of a non-bonding diatomic Pt2-ND@G catalyst via a two-step atomic layer deposition for the selective hydrogenation of m-dinitrobenzene. Aberration-corrected high-resolution scanning transmission electron microscopy combined with X-ray absorption spectroscopy reveals that Pt2-ND@G predominantly contains high-density non-bonding Pt diatomic sites with well-tuned electronic interactions. Pt2-ND@G achieves complete m-dinitrobenzene conversion with >99.0% selectivity toward m-phenylenediamine and retains high stability over five cycles under mild conditions, outperforming reference catalysts including isolated single atoms, fully exposed clusters, and nanoparticles. Experimental and theoretical studies further suggest that the electron-deficient non-bonding diatomic Pt sites synergistically activate both m-dinitrobenzene and hydrogen, while also promoting the efficient desorption of m-phenylenediamine. This work highlights the structural and electronic advantages of high-density diatomic catalysts for multi-step hydrogenation and offers a versatile platform for catalyst design. Balancing activity and selectivity limits the performance of many catalysts in fine chemical hydrogenation. This study shows that paired platinum atoms work together to fully convert a nitroarene into its diamine with enhanced catalytic activity, high selectivity and good recyclability.
Chen et al. (Wed,) studied this question.