Boosting hydrogenation properties of Pt single-atom catalysts via tailoring the electronic structures by coordination number regulation

Abstract

Clarifying the relationship of single metal atom coordination structures and catalytic properties is crucial for the fine-design of highly-efficient catalysts, but systematically manipulating the coordination structure (e.g., coordination numbers (CN) of metal atoms) without changing atomic dispersion is challenging. Herein, we develop a precursor-atomization strategy for the synthesis of single-atom catalysts (SACs) and further precisely tailor Pt-N CN by changing the pyrolysis sequence and atmosphere. It is found that as Pt-N CN decreases (from Pt-N5 to Pt-N3), the electron density of Pt atoms increases and the energy barrier for H2 dissociation decreases, thus achieving a ∼550-fold increase in activity of selective hydrogenation of 3-nitrophenylacetylene (reduction of nitro group while maintaining the highly sensitive alkyne group), successfully breaking the selectivity-activity seesaw. Additionally, Pt-N3 SACs also show remarkably broad applicability for the hydrogenation of nitroarenes (even for iodo-nitrobenzene) due to its unique heterolytic cleavage path of H2 and preferential adsorption of nitro group.