Preparation of gold nanoparticles and carbon dots by hydrothermal reaction of bovine haemoglobin with chloroauric acid and energy band bending in carbon dots

Abstract

The incubation and hydrothermal reaction under alkaline condition of bovine haemoglobin with chloroauric acid were investigated. The products in the supernatant from the centrifuge were found to be gold nanoparticles and carbon dots. Greigite (Fe3S4) was found as a byproduct in the precipitation. In the incubation process, the reduction ability of bovine haemoglobin molecules was activated under alkaline condition (pH ≈ 12), and Au(III) ions underwent progressive reduction to form Au nanoparticles in situ. In the hydrothermal reaction, denatured bovine haemoglobin molecules underwent biomineralisation to form carbon dots and greigite. Photoluminescence was used as a measurement of the energy band bending of as-prepared carbon dots. The effects of the acceptor 4-nitrotoluene and donor N,N-diethylaniline molecules on the photoluminescence intensity imply that oxygen-contained surface groups induce the upward band bending of carbon dots.

Keywords

• Au nanoparticles
• carbon dots
• bovine haemoglobin
• energy band bending