Acceptorless dehydrogenation and hydrogenation of N- and O-containing compounds on Pd₃Au₁(111) facets.

Abstract

Catalytic dehydrogenation and hydrogenation of amines and alcohols are important in the synthesis of fine chemicals. Despite several efficient homogeneous catalysts having been identified, highly active heterogeneous catalysts remain elusive, although they would meet an unmet need. Here, we show that bimetallic Pd-Au nanoparticles with Pd-to-Au molar ratios of 3:1 immobilized on multiwall carbon nanotubes (Pd₃Au₁/CNT) display high catalytic activity in the oxidant-free and acceptorless dehydrogenation and hydrogenation of N- and O-containing heterocyclic compounds, amines/imines, and alcohols/ketones. Transmission electron microscopy analysis demonstrates the preferential exposure of Pd₃Au₁(111) facets on the Pd₃Au₁/CNT catalyst. Mechanistic insights combining experimental data with density functional theory calculations reveal that the Pd₃Au₁(111) surface enhances both dehydrogenation and hydrogenation reactions and provides a rationale for the observed enhancements.