Synthesis of surface layered hierarchical octahedral-like structured Zn2SnO4/SnO2 with excellent sensing properties toward HCHO

An uniform surface layered hierarchical octahedral-like structured Zn2SnO4/SnO2 had been achieved through a simple chemical route with post heat-treatment. The structures of Zn2SnO4/SnO2 composites can be readily tailored from sphere, hierarchical octahedral-like structure to perfect octahedron simply by adjusting the reaction solution temperatures. The as-prepared Zn2SnO4/SnO2 composites were used as sensing materials to detect formaldehyde (HCHO) and other volatile organic compounds (VOCs). Among all the sensors of Zn2SnO4/SnO2, the sensor based on hierarchical octahedral-like Zn2SnO4/SnO2-20 degrees C demonstrated the most excellent response toward HCHO, which presented high sensitivity, wide detection limit, excellent stability/reversibility and distinguished selectivity. Such good sensing performance is mainly ascribed to the unique surface layered hierarchical octahedral-like structure. Zn2SnO4/SnO2-20 degrees C has uniform particles with smaller size and as much as possible exposed surface, resulting in large specific surface area, much active adsorption/interaction sites, narrow mesopore size distribution and proper pore volume which are beneficial to the gas sensing. This work renders a great way to improve the sensing characteristics by using a surface hierarchical structure material. (C) 2016 Elsevier B.V. All rights reserved.