One-pot synthesis of AC/ZnO nanocomposites for highly sensitive, repeatable and fast response humidity sensor

Soren, D and Kumar, K and Deheri, PK and Pattojoshi, P (2024) One-pot synthesis of AC/ZnO nanocomposites for highly sensitive, repeatable and fast response humidity sensor. In: Ceramics International .

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Abstract

A highly sensitive and repeatable humidity sensor that can measure relative humidity at room temperature (25 °C) was fabricated using activated carbon-ZnO (AC/ZnO) nanocomposites. The AC/ZnO nanocomposites with high oxygen vacancies were prepared by a facile one-pot synthesis method through carbonization of ZnCl2-impregnated biomass precursor. The sensor exhibited a better response (96 at 0.5 V biasing), short response time (17.4 s), and recovery time (32.1 s). The same 96 relative response at 0.5V biasing for all four consecutive cycles was observed without losing the response-recovery time, indicating excellent repeatability. On the other hand, biomass-derived single-phase activated carbon (AC) did not respond to humidity change at room temperature. The improved humidity sensing in AC/ZnO nanocomposites was ascribed to the synergistic effects of increased oxygen vacancies, increased active sites in the AC phase, and the formation of p�n heterojunction at the composite interface, substantiated with X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS) studies. The sensing mechanism of AC/ZnO nanocomposite was discussed based on the enhanced reduction of H2O by adsorbed O2� at AC/ZnO heterojunction, leading to increasing sensor resistance. © 2024

Item Type:	Journal Article
Publication:	Ceramics International
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd
Keywords:	Carbonization; Heterojunctions; Humidity sensors; II-VI semiconductors; Nanocomposites; Oxygen vacancies; Supercapacitor; X ray photoelectron spectroscopy; Zinc chloride; Zinc oxide, Activated carbon-ZnO nanocomposite; Carbonisation; Fast response; High oxygen vacancies; One-pot synthesis; Recovery time; Relative response; Short response time; Synthesis method; ZnO, Activated carbon
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	29 Jul 2024 09:01
Last Modified:	29 Jul 2024 09:01
URI:	http://eprints.iisc.ac.in/id/eprint/85200

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