Gold nanoparticle-decorated reduced graphene oxide (rGO) as a highly reactive catalyst for the selective α,β-dehydrogenation of N-methyl-4-piperidone

Gold nanoparticles (AuNPs) supported on reduced graphene oxide (AuNPs/rGO) were demonstrated to be a highly reactive catalyst for the selective α, β-oxidative dehydrogenation (ODH) of N-methyl-4-piperidone as a model substrate for β-N-substituted saturated ketones. This substrate was chosen due to the significant pharmaceutical relevance of the reaction product 1-methyl-2,3-dihydropyridin-4(1H)-one which is very expensive (>1000 €/g), in contrast to the inexpensive starting material (0.15 €/g). Various synthesis methods were employed to prepare AuNPs supported on different carbon materials, including reduced graphene oxide (rGO), activated carbon (AC), and carbon black (CB), to investigate the influence of the carbon support on the catalyst performance. As stabilizing agents for the AuNPs citrate (Cit) and the polyoxometallate [SiW ₉ O ₃₄ ] ^10– (SiW ₉ ) were used. Among the tested catalysts, the rGO-supported ones, Au-Cit/rGO, Au-SiW₉/rGO, Au@SiW₉/rGO and exhibited superior catalytic activity for the selective oxidation reaction. These findings offer valuable insights for the design of highly active Au-based catalysts for the dehydrogenation of β-N-substituted saturated ketones and other fine chemical applications.