Novel p-n heterojunction Co3O4/AlOOH composites materials for gas sensing at room temperature

In this work, Co3O4/AlOOH composite materials were synthesized via a two-step method, where cobalt oxide/aluminum oxide intermediate was first synthesized by hydrothermal method, then followed by calcinations in air. The structure and morphology of the samples are characterized by XRD, FT-IR and TEM etc. The as-prepared Co3O4/AlOOH composite materials display special 2D nanosheets and mesopore structure. The small Co3O4 nanoparticles with sizes about 7 nm are highly dispersed on the surface of AlOOH. Mott-Schottky plots displaying the p-n junctions are existent in the composite materials. The gas sensing results reveal that the 1:9 Co3O4/AlOOH composite materials gas sensor shows significantly enhance NOx gas sensing performance. The Co3O4/AlOOH composite materials sensor shows responses of 57.8-7.5% to 100-0.1 ppm of NOx at room temperature. The outstanding NOx gas sensing performance may attribute to the structure of the Co3O4/AlOOH composite materials and the formation of the p-n junctions in materials. (C) 2017 Published by Elsevier B.V.