Effect of multi-walled carbon nanotubes on the visible light photocatalytic activity of AgInS2 for Rhodamine B degradation
Jianyun Yang, Xinyue Gu, Liqiong Yang, Minghua Li, Ya Yan, Ye Zhang
Abstract
Visible-light responsive AgInS 2 (AIS) nanoparticles modified with either pristine multi-walled carbon nanotubes ( p -MWCNTs) or mixed-acid (H 2 SO 4 and HNO 3 ) oxidized multi-walled carbon nanotubes ( o -MWCNTs) were synthesized using a low-temperature liquid phase method. The resulting nanocomposites are denoted as p -MWCNTs/AIS or o -MWCNTs/AIS. The structure, morphology, and optical properties of the samples were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), photoluminescence spectroscopy (PL), and ultraviolet-visible diffuse reflectance spectroscopy (UV–Vis DRS). The photocatalytic activity of p / o -MWCNTs/AIS towards the degradation of Rhodamine B (RhB) was investigated, and the optimal proportion of p/o -MWCNTs introduced on AIS was determined. A possible degradation mechanism of RhB over p / o -MWCNTs/AIS was proposed. The results demonstrated that p / o -MWCNTs were successfully incorporated into AIS, and the addition of an appropriate amount of p / o -MWCNTs improved the visible-light photocatalytic activity of AIS. Among the samples, 2 % o -MWCNTs/AIS exhibited the highest visible-light catalytic activity , achieving a degradation efficiency of 95 % within 40 min. The·⋅O 2 − species were identified as the main active species during the photocatalytic degradation process . The introduction of o -MWCNTs not only facilitated the separation of photogenerated electron-hole pairs (e − /h + ) in AIS but also enhanced the visible-light absorption of AIS, leading to a significant improvement in its photocatalytic performance. Furthermore, the incorporation of o -MWCNTs greatly enhanced the cycling stability of AIS for reuse.