▎ 摘　　要

Two-dimensional (2D) nanomaterials and their composites have become a popular area among researchers owing to their superior properties which can be attributed to the planar structure. In this work, we used a hydrothermal method to generate ultrathin SnO2 nanosheets with thickness of similar to 5nm on the reduced graphene oxide (rGO) layer to construct sheet-on-sheet heterostructured architectures. The sensor response of rGO/SnO2 nanosheets composites is 11.9 to 100ppm formaldehyde at the optimal operating temperature of 220 degrees C. Besides of the superior sensor response at lower working temperature, the rGO/SnO2 nanosheets composites sensor exhibited good selectivity and fast response/recover performance. These strengths revealed the promising applications of the rGO/SnO2 nanosheets composites in practical detection. The present work definitely reveals the advantages of rGO/SnO2 nanosheets composites featured with a sheet-on-sheet architecture between two different nanosheets in gas sensing applications.