Colloidal synthesis of tungsten oxide quantum dots for sensitive and selective H2S gas detection

Abstract

Tungsten oxide (WO3) has been intensely investigated as an important gas-sensing materials. Here the sensitive and selective H2S gas sensors based on WO3 quantum dots that were synthesized via a colloidal process using WCl6 ethanol solutions mixed with oleic acid and oleylamine were demonstrated. The solution processability of the colloidal WO3 quantum dots enabled a room-temperature sensor fabrication without high-temperature sintering. The optimal sensor response toward 50ppm of H2S is 57 with the response time of 47s, and the response was fully recoverable upon H2S release at 80°C. The sensing mechanism was discussed by using first-principles calculation based on density functional theory (DFT). Their highly sensitive and fast response at lower operating temperature, combined with the benefit of ease fabrication, make the colloidal tungsten oxide quantum dots highly attractive for the construction of low cost gas sensor with reduced power consumption.