Nanoscale Pd catalysts decorated WO3–SnO2 heterojunction nanotubes for highly sensitive and selective acetone sensing

Abstract

In this study, we report on the construction of multiple heterojunctions by functionalization of WO3–SnO2 n–n junction nanotubes (NTs) with nanoscale Pd catalysts for highly sensitive and selective acetone sensing. WO3–SnO2 n–n junction NTs with various W/Sn molar ratios were fabricated via an electrospinning technique. Pd decoration of WO3–SnO2 NTs was further developed by a chemical deposition method. As a result, the enhancement of sensing selectivity and sensitivity to acetone and reduction of operating temperature were simultaneously achieved. The enhanced sensing characteristics of Pd@WO3–SnO2 NTs were mainly ascribed to the formation of multiple heterojunctions (WO3–SnO2 n–n junctions, PdO–SnO2 and PdO–WO3 p–n junctions) and chemical sensitization effect of Pd nanocatalysts. The present results demonstrate that porous WO3–SnO2 heterojunction NTs decorated with nanoscale Pd catalysts have a good potential for sensitive and selective detection of acetone.