Improvement visible-light photocatalytic performance of single-crystalline SnSe1±x NPs toward degradation of organic pollutants

Abstract

SnSe NPs with different Se/Sn ratios (Se/Sn = 0.7–1.3) were synthesized by a simple co-precipitation method in the ambient conditions. X-ray diffraction pattern (XRD), high-resolution transmission electron microscopy (HRTEM) images, and selected area electron diffraction (SAED) patterns showed that the sample with Se/Sn = 1.2 ratio was included a single-crystal structure without any defects. In addition, the XRD pattern indicated that, there was an optimum ratio for obtaining SnSe phase, which was 0.8≤(Se/Sn)≤1.2. The photocatalytic activity results of the samples showed that, we were faced with the ultra-fast photocatalytic materials to degrade organic pollutants under the visible light irradiation conditions. Reusability test and XRD pattern result after the photocatalytic activity revealed that only sample with Se/Sn = 1.2 ratio was a stable photocatalytic material. Photoluminescence (PL) indicated that, the efficient electron-hole separation was higher for the Se-rich sample in comparison to another samples. Mott-Schottky (MS) and Brunauer-Emmett-Teller (BET) results indicated that, the flat-band potential (Vfb) shift and the enhancement textural parameters of the sample with Se-rich condition, which was the single-crystalline NPs, in compared with the other samples were the most important factors to enhance the photocatalytic performance. Besides, electrochemical impedance spectroscopy (EIS) results indicated that the sample with Se-rich condition had lower charge transfer resistance, which is a very important parameter to enhance the photocatalytic performance.