Synthesis and H₂S Sensing Properties of CuO−SnO₂ Core/Shell PN-Junction Nanorods

One-dimensional nanosized core/shell PN-junctions are formed from N-type SnO 2 nanorods (synthesized via a hydrothermal method; diameter ∼10 nm, length ∼100 nm) uniformly coated with P-type CuO nanoparticles (diameter ∼4 nm). Gas sensors are realized from these PN-junction nanorods, and their resistances greatly decrease upon exposed to H 2 S at room temperature. The sensitivity against 10 ppm H 2 S at 60 °C is up to 9.4 × 10 6 . At the same time, the sensors have very good selectivity against H 2 S. Such good performances are probably attributed to the destruction of PN-junctions and the small size effect of nanostructures. Our results imply that one-dimensional heterostructured nanomaterials are promising candidates for high-performance gas sensors.