De Novo Synthesis of Gold‐Nanoparticle‐Embedded, Nitrogen‐Doped Nanoporous Carbon Nanoparticles (Au@NC) with Enhanced Reduction Ability

Abstract

Abstract A de novo synthesis of gold‐nanoparticle‐embedded, nitrogen‐doped nanoporous carbon nanoparticles (Au@NC) was investigated in this work. Chloroauroic acid was encapsulated inside zeolitic imidazolate framework‐8 (ZIF‐8) nanoparticles during the synthesis and later reduced into gold nanoparticles. The as‐synthesized gold‐nanoparticle‐embedded ZIF‐8 (Au@ZIF‐8) was then carbonized into Au@NC to enhance the stability of the nanoporous support. The results show that Au@NC exhibits a porous structure containing 3 wt % of gold. 2‐Methylimidazole provided an abundant amount of nitrogen (19 wt %) on the carbon matrix, which resulted in a hydrophilic and positively charged surface that is useful for the reduction of 4‐nitrophenol. The results of the catalytic reaction indicate that synthesized Au@NC could act as an effective catalyst with a turnover frequency (TOF) of 1185 g −1 s −1 , which is higher than that of conventional naked Au nanoparticles (TOF: 339 g −1 s −1 ) and that of Au nanoparticles on activated carbon (TOF: 89 g −1 s −1 ). We propose that the enhanced performance of Au@NC resulted from homogeneous distribution of Au nanoparticles along with the hydrophilic and positively charged nitrogen‐doped carbon surface.