Novel Two-Dimensional WO 3 /Bi 2 W 2 O 9 Nanocomposites for Rapid H 2 S Detection at Low Temperatures.

Compared with single-component metal oxides, multicomponent metal oxides show good gas sensing performance in the field of gas sensing, but they still need to be further improved in terms of rapid response. In this paper, a two-dimensional flaky WO ₃ /Bi ₂ W ₂ O ₉ composite material with a thickness of about 32.3 nm was synthesized by a simple solvothermal method. The composite has good sensing performance and selectivity toward H ₂ S. When the operating temperature is as low as 92 °C, the response to 100 ppm H ₂ S reaches 84.18, and the response time is 2 s, which is extremely fast due to the open system of the two-dimensional nanosheet. A combination of gas chromatography-mass spectrometry (GC-MS) and X-ray photoelectron spectroscopy (XPS) is used to analyze the changes of H ₂ S and the surface chemistry of WO ₃ /Bi ₂ W ₂ O ₉ composite materials; the sensing mechanism of H ₂ S was studied by a Kelvin probe and UV diffuse reflection. Compared with the pure phase WO ₃ and Bi ₂ W ₂ O ₉ , good gas sensing properties of the WO ₃ /Bi ₂ W ₂ O ₉ composite may be due to its unique heterostructure. This is the first application of WO ₃ /Bi ₂ W ₂ O ₉ in the field of gas sensing and is of great significance for the rapid detection of H ₂ S at low temperatures for multicomponent metal oxides.