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 SnO2 nanorods (synthesized via a hydrothermal method; diameter similar to 10 nm, length similar to 100 nm) uniformly coated with P-type CuO nanoparticles (diameter similar to 4 nm). Gas sensors are realized from these PN-junction nanorods, and their resistances greatly decrease upon exposed to H2S at room temperature. The sensitivity against 10 ppm H2S at 60 degrees C is up to 9.4 x 10(6). At the same time, the sensors have very good selectivity against H2S. 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.