Highly selective NO2 sensor based on Au/SnS2 nano-heterostructures via visible-light modulation

The efficient monitoring of toxic nitrogen dioxide (NO 2 ) reveals a great practical significance in terms of environmental protection and human health. Tin disulfide (SnS 2 ) has recently presented bright application prospects for the NO 2 detection owing to its unique physiochemical properties. Unfortunately, the pristine SnS 2 -based gas sensor suffers from inferior selectivity to NO 2 since the emerging cross-response over interfering gases (especially to NH 3 ) at room temperature. Herein, a room-temperature-operated gas-sensitive device based on Au nanoparticles decorated SnS 2 nanosheet was proposed for the highly selective detection towards NO 2 by exploiting visible-light modulation. Benefited from the electronic sensitization and chemical sensitization of Au nanoparticles, the Au/SnS 2 gas sensor presented a visibly enhanced response toward 1 ppm NO 2 compared with pristine SnS 2 gas sensor, while its selectivity to NO 2 over NH 3 only increased by 35%. Further, through effectively modulating the adsorption and reaction behavior of gas molecules by introducing visible-light excitation, the Au/SnS 2 gas sensor manifested an excellent selectivity with 130% gain in detecting 1 ppm NO 2 at room temperature, endowed the robust repeatability and reliable long-term stability. This work thus demonstrates that the visible-light modulation can serve as a promising technique for exploiting highly selective gas-sensitive devices operating at room temperature.