A combined experimental and theoretical study of composite SnO2–BiVO4 for selective NO2 sensing

Tin oxide-bismuth vanadate heterostructures (SnO2–BiVO4) exhibit considerably enhanced surface-exposed edge sites with an abundance of the dangling bond due to their intrinsic crystallographic anisotropy. Its high chemical reactivity and chemisorption capabilities make it ideal for high-performance electrochemical sensing. In this paper, Tin oxide-bismuth vanadate heterostructures (SnO2–BiVO4) were synthesized using a simple hydrothermal synthesis method and employed as room temperature NO2 sensor. X-ray diffractometers (XRD), scanning electron microscopes (SEM), and transmission electron microscopes. (TEM), X-ray photoelectron spectrometer (XPS) and ultraviolet–visible spectrometer (UV–vis) were used to examine the heterogeneous structure of as-synthesized SnO2–BiVO4. The as-prepared SnO2–BiVO4 (1:1) revealed optimal gas-sensing performance toward 0.1 ppm–1 ppm NO2 at a relatively low optimal operating temperature (298 K), including fast response, fast recovery, high sensitivity and good reproducibility. The experimental results demonstrated that the as-synthesized SnO2–BiVO4 has enormous future potential for real-time detection of NO2 traces at room temperature. Density Functional Theory (DFT) calculations were analyzed to reveal the underlying principles behind the experimentally observed improvement.