▎ 摘　　要

We report the use of a scanning Kelvin probe in measuring the gas adsorption induced change in contact potential difference (CPD) for the graphene-based binary nanocomposites towards various volatile organic compounds (VOCs) at room temperature. The binary nanocomposites (GO/SnO2) were prepared by one-step solvothermal (GS-I) and two-step mechanical mixing (GS-II) methods. The significant change in CPD upon visible light illumination for both the samples in the air medium enabled a room temperature interaction with VOCs. GS-I exhibited superior structural, optical and electrical properties in terms of lower crystallite size, defects, a higher percentage of surface atoms and visible light absorption. This appears to be consistent with the change in surface potential upon VOC interaction with a downward band bending for GS-I and upward bending for GS-II. These findings provided substantial details for understanding the interfacial modifications between graphene-based binary nanocomposites and assist in characterizing the mechanism of gas interaction.