Yolk-shelled ZnCo2O4 microspheres: Surface properties and gas sensing application

Author(s)

Joshi, Nirav ^{[1, 2]} ; da Silva, Luis F. ^[3] ; Jadhav, Harsharaj S. ^[4] ; Shimizu, Flavio M. ^[2] ; Suman, Pedro H. ^[5] ; M'Peko, Jean-Claude ^[2] ; Orlandi, Marcelo Ornaghi ^[5] ; Seo, Jeong Gil ^[4] ; Mastelaro, Valmor R. ^[2] ; Oliveira, Jr., Osvaldo N. ^[2]

Affiliation

^[1] Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 - USA

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, CP 369, BR-13560970 Sao Carlos, SP - Brazil

^[3] Univ Fed Sao Carlos, Dept Phys, Rodovia Washington Luis Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[4] Myongji Univ, Dept Energy Sci & Technol, Yongin - South Korea

^[5] Sao Paulo State Univ, Inst Chem, Dept Phys Chem, POB 355, BR-14800900 Araraquara, SP - Brazil

• Document type: Journal article
• Source: SENSORS AND ACTUATORS B-CHEMICAL; v. 257, p. 906-915, MAR 2018.
• Web of Science Citations: 60

Abstract

The need to improve the sensitivity, selectivity and stability of ozone gas sensors capable of monitoring the environment to prevent hazard to humans has sparked research on binary metal oxides. Here we report on a novel ozone gas sensor made with ca. 0.5 mu m yolk-shelled ZnCo2O4 microstructures synthesized via an eco-friendly, co-precipitation method and subsequent annealing. With these ZnCo2O4 microspheres, ozone concentrations down to 80 parts per billion (ppb) could be detected with a.c. and d.c. electrical measurements. The sensor worked within a wide range of ozone concentrations, from 80 to 890 ppb, being also selective to ozone compared to CO, NH3 and NO2. The high performance could be attributed to the large surface area to volume ratio inherent in yolk-shell structures. Indeed, ozone molecules adsorbed on the ZnCo2O4 surface create a layer of holes that affect the conductivity, as in a p-type semiconductor. Since this mechanism of detection is generic, ZnCo2O4 microspheres can be further used in other environment monitoring devices. (c) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/14262-7 - Nanostructured films from biologically-relevant materials
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/23474-6 - Nanomaterial-based heterostructures: synthesis and their gas sensing properties
• Grantee: Niravkumar Jitendrabhai Joshi
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 14/23546-1 - Enhanced sensitive and selective sensors made with p-NiO nanowire/n-ZnO Nanowire heterostructures
• Grantee: Niravkumar Jitendrabhai Joshi
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/15543-7 - Biosensors to detect Escherichia coli using the concept of an extended electronic tongue
• Grantee: FLAVIO MAKOTO SHIMIZU
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC