UV-activated efficient formaldehyde gas sensor based on cauliflower-like graphene-modified In-doped ZnO at room temperature

So far, for photoelectric metal oxide semiconductor gas sensors, it is a huge bottleneck to achieve high response performance and low detection limit of formaldehyde at room temperature. This work introduced the synthesis of cauliflower-like graphene-modified In-doped ZnO (GR/In-ZnO) composites via a facile one -pot method with a large comparative surface area for low-concentration formaldehyde sensing at room temperature. GR/In-ZnO-30 0 showed the highest response to 10 ppm formaldehyde, up to 1891%, which was 12 times that of In-ZnO-30 0. In addition, the theoretical detection limit of GR/In-ZnO-30 0 was as low as 13 ppb, and the response at this concentration was 137%. Through the characterization of Surface Photovoltage (SPV), Transient Photovoltage (TPV), Surface Photocurrent (SPC), X-ray Photoelectron Spectroscopy (XPS), and nitrogen gas adsorption isotherms, good formaldehyde sensing performance of GR/ In-ZnO-30 0 was attributed to the excellent separation and transmission capacity of photogenerated car-riers, the high specific surface area (109.2 m(2)/g), and abundant oxygen defects on the surface. This work provides a feasible strategy for the design of low-concentration formaldehyde sensing materials with a rapid response at room temperature.(c) 2022 Elsevier B.V. All rights reserved.