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

The efficient monitoring of toxic nitrogen dioxide (NO2) reveals a great practical significance in terms of envi-ronmental protection and human health. Tin disulfide (SnS2) has recently presented bright application prospects for the NO2 detection owing to its unique physiochemical properties. Unfortunately, the pristine SnS2-based gas sensor suffers from inferior selectivity to NO2 since the emerging cross-response over interfering gases (especially to NH3) at room temperature. Herein, a room-temperature-operated gas-sensitive device based on Au nano -particles decorated SnS2 nanosheet was proposed for the highly selective detection towards NO2 by exploiting visible-light modulation. Benefited from the electronic sensitization and chemical sensitization of Au nano -particles, the Au/SnS2 gas sensor presented a visibly enhanced response toward 1 ppm NO2 compared with pristine SnS2 gas sensor, while its selectivity to NO2 over NH3 only increased by 35%. Further, through effectively modulating the adsorption and reaction behavior of gas molecules by introducing visible-light excitation, the Au/ SnS2 gas sensor manifested an excellent selectivity with 130% gain in detecting 1 ppm NO2 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 oper-ating at room temperature.