Phenylalanine Dipeptide-Regulated Ag/In2O3 Nanocomposites for Enhanced NO2 Gas Sensing at Room Temperature with UV Illumination

Abstract

This work demonstrates that phenylalanine dipeptide-regulated silver can improve the gas sensing performance of a nitrogen dioxide (NO2) gas sensor. Herein, Ag/In2O3 was prepared by a hydrothermal method to detect NO2 gas, where varying amounts of phenylalanine dipeptide (FF) were introduced to regulate the growth of Ag NPs. The morphologies, microstructures, and compositions of the obtained samples were characterized in detail, and the results indicate that Ag NPs grow into nanorods with the regulation of FF. The gas sensing characteristics were systematically investigated with UV illumination (365 nm) at room temperature (25 °C). Upon exposure to NO2 gas, the optimal sensor exhibits a relatively high response value, good linearity, and satisfactory stability. In addition, the sensor can maintain good gas sensing performance under varying humidity. The reason underlying the observed enhancement in the gas sensing property is the formation of more active sites with the Ag nanorod structure. This study suggests that the introduction of polypeptides is a promising idea to improve the performance of gas sensors.