Construction of 1D SnO 2 -coated ZnO nanowire heterojunction for their improved n-butylamine sensing performances

Abstract

One-dimensional (1D) SnO 2 -coated ZnO nanowire (SnO 2 /ZnO NW) N-N heterojunctions were successfully constructed by an effective solvothermal treatment followed with calcination at 400 °C. The obtained samples were characterized by means of XRD, SEM, TEM, Scanning TEM coupled with EDS and XPS analysis, which confirmed that the outer layers of N-type SnO 2 nanoparticles (avg. 4 nm) were uniformly distributed onto our pre-synthesized n-type ZnO nanowire supports (diameter 80∼100 nm, length 12∼16 μm). Comparisons of the gas sensing performances among pure SnO 2, pure ZnO NW and the as-fabricated SnO 2 /ZnO NW heterojunctions revealed that after modification, SnO 2 /ZnO NW based sensor exhibited remarkably improved response, fast response and recovery speeds, good selectivity and excellent reproducibility to n-butylamine gas, indicating it can be used as promising candidates for high-performance organic amine sensors. The enhanced gas-sensing behavior should be attributed to the unique 1D wire-like morphology of ZnO support, the small size effect of SnO 2 nanoparticles, and the semiconductor depletion layer model induced by the strong interfacial interaction between SnO 2 and ZnO of the heterojunctions. The as-prepared SnO 2 /ZnO NW heterojunctions may also supply other novel applications in the fields like photocatalysis, lithium-ion batteries, waste water purification, and so on.