Size-dependent work function and catalytic performance of gold nanoparticles decorated graphene oxide sheets

•Illustrated physical adsorption of gold nanoparticles on graphene oxide plane.•Work function significantly shifted down as gold nanoparticle size reduced to 5 nm.•Smaller gold nanoparticle resulted in enhanced catalytic properties.•Graphene oxide supported gold nanoparticles to act as a highly efficient catalyst.•Enhanced electron transfer at interlayer greatly improved catalytic performance.

We investigated the size-dependent work function and catalytic performance of gold nanoparticles (AuNPs) decorated graphene oxide (GO). The ultraviolet photoelectron spectroscopic analysis revealed that the work function decreased from 5.76 to 5.35 eV as the AuNP size was reduced from 40 to 5 nm. The catalytic performance of GO:AuNP hybrids was evaluated from the reduction of o-nitroaniline to 1,2-benzenediamine using sodium borohydride as a reducing agent. A considerable increase of the reaction rate constant with decreasing AuNP size is due to the enhanced surface interaction of AuNPs. Improved o-nitroaniline adsorption and electron transfer at the Au/GO interface leads to better catalytic activity, and this is more noticeable at an AuNP size of 5 nm. Our result indicates that GO:AuNP hybrids have considerable potential for use in industry wastewater treatment.

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