Study on AuNPs size regulation and AuNPs/BP photocatalytic performance

As a new two-dimensional material, black phosphorus (BP) has many advantages, like layer-dependent direct band gap, wide spectral response, high carrier mobility and abundant active sites. It is widely used in photocatalysis, solar energy conversion and other fields. However, the rapid recombination of photo-generated carriers and poor chemical stability limit the development of BP in the field of photocatalysis. In this study, a composite photocatalyst was configurated by loading Au nanoparticles (AuNPs) on the surface of the BP, namely AuNPs/BP. By adjusting the conditions such as reducing agent, protective agent, temperature, gold source in the reaction system, the mechanism and influencing factors of AuNPs particle size were explored. The composite catalyst was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible spectrometry (UV–vis), X-ray photoelectron energy spectrometry (XPS), and photochemical test platforms. Next, the catalytic performance of AuNPs/BP was evaluated by photocatalytic degradation of methyl orange (MO). The results showed that the degradation performance of AuNPs/BP on MO is significantly better than that of pure BP, and the degradation rate increased from 49.7% to 67.7%. The apparent rate constant increased from 5.726 × 10−3min−1 to 9.418 × 10−3min−1. Due to the surface proton resonance effect of AuNPs, BP with AuNPs evenly loaded on the surface showed strong absorption of visible light, high carrier separation efficiency, and widened the band gap of BP.