Facile synthesis cedar-like SnO2 hierarchical micro-nanostructures with improved formaldehyde gas sensing characteristics

Abstract

In this work, well-defined cedar-like SnO2 hierarchical micro-nanostructures have been successfully synthesized through a facile low-temperature hydrothermal method. XRD, SEM, TEM and HRTEM were carried out to investigate morphology and structure of as-obtained products. The morphology can be tailored by modulating the reaction temperature and annealing temperature. It is observed that the cedar-like SnO2 micro-nanostructure are composed of two parts: the “trunk” and “leaves”. The trunk is composed of a hexagonal-pyramid, and the leaves are constructed by numerous ordered triquetrous nanosheets. As-fabricated cedar-like SnO2 micro-nanostructure based sensors exhibit fast response time (<1 s)/recovery time (13 s), high sensitivity, good repeatability, and good sensing selectivity towards formaldehyde gas at lower working temperatures. A possible reaction formation mechanism of the cedar-like micro-nanostructure and a morphology-dependent sensing mechanism are proposed.