Corrugated Cobalt Titanate/Partially Reduced Graphene Oxide Heterojunctions for a Selective Isopentanol Gas Sensor

It is well-established that a high specific surface area and more active sites are the key factors for excellent gas sensing performances. Corrugated-morphology materials expose large surface areas and a variety of low-coordination atoms, which can promote gas adsorption and catalyze sensing reactions. In this work, corrugated cobalt titanate/partially reduced graphene oxide (CoTiO3/prGO) heterogeneous sensing materials are prepared by a sol–gel method combined with a controlled chemical reduction process. A green and ecofriendly reducing agent ascorbic acid (VC) is used to regulate the reduction process. An appropriate dosage of VC induces partial removal of functional groups from graphene oxide (GO) together with a periodical relaxation of the aromatic plane, forming a corrugated-morphology prGO. Excessive use of VC leads to asymmetrical or random removal of functional groups, leading to a wrinkled or porous morphology. The obtained corrugated CoTiO3/prGO exhibits high sensitivity to the isopentanol molecule. The response value reaches 30.1–100 ppm isopentanol, which is 3.2–10.4 times that of pentanol, pentanal, glutaral, and methylcyclopentane. The selectivity of CoTiO3/prGO to isopentanol is attributed to the corrugated morphology, the abundant C–O–Ti chemical bonds as activated adsorption sites, and the heterogeneous interfaces. This work offers a mild chemical reduction strategy to effectively regulate the morphological revolution, heterojunction formation, and selective sensing performance of the CoTiO3/prGO composite.