Design of a highly sensitive ethanol sensor using a nano-coaxial p-Co3O4/n-TiO2 heterojunction synthesized at low temperature.
In this paper, we describe the design, fabrication and gas-sensing tests of nano-coaxial p-Co3O4/n-TiO2 heterojunction. Specifically, uniform TiO2 nanotubular arrays have been assembled by anodization and used as templates for generation of the Co3O4 one-dimensional nanorods. The structure morphology and composition of as-prepared products have been characterized by SEM, XRD, TEM, and XPS. A possible growth mechanism governing the formation of such nano-coaxial heterojunctions is proposed. The TiO2 nanotube sensor shows a normal n-type response to reducing ethanol gas, whereas TiO2-Co3O4 exhibits p-type response with excellent sensing performances. This conversion of sensing behavior can be explained by the formation of p-n heterojunction structures. A possible sensing mechanism is also illustrated, which can provide theoretical guidance for the further development of advanced gas-sensitive materials with p-n heterojunction.
School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China. xjyang@tju.edu.cn.
Y Q
YQ
Liang
Z D
ZD
Cui
S L
SL
Zhu
Z Y
ZY
Li
X J
XJ
Yang
Y J
YJ
Chen
J M
JM
Ma
D003035:Cobalt / Q000737:chemistry*; D055664:Electrochemical Techniques; D000431:Ethanol / Q000032:analysis*; D005740:Gases / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D012666:Semiconductors; D013696:Temperature; D014025:Titanium / Q000737:chemistry*
D005740:Gases; D010087:Oxides; C009495:titanium dioxide; D003035:Cobalt; D000431:Ethanol; D014025:Titanium; C060728:cobalt oxide