Molten Salt-Mediated Surface Reconstruction Induced Orientation-Growth of 1D/2D Heterostructure for High-Sensitivity H2S Gas Sensing

Multi-dimensional heterostructure with integrative dimensionality and synergic effects are intriguing, but the rational synthesis and further study into the influence of structure on the surface reaction performance are still urgent tasks. Here, we report a molten salt mediated method to synthesize 1D/2D heterostructure. Particularly, the Sn-O bonds and Cu-O bonds on the surface of materials can be destabilized due to the strong polarization of LiCl-KCl molten salt, and the newly formed CuCl species can be homogeneously dispersed in amorphous SnOx. Notably, the surface reconstruction induced orientation-growth of 1D Cu-doped SnO2 single crystal occurs in the recrystallization process to form the 1D nanoribbon/2D nanosheet. As a proof of the concept, the unique 1D/2D heterostructure integrate the merits of fast electron transfer and numerous surface active O2–(ad) species, which endow it superior gas sensing performance to H2S. Experimental and theoretical studies reveal high sensing response (Ra/Rg = 132.6 to 1 ppm), fast response and recovery rate (10 s and 72 s) and high selectivity at 150 °C is attributed to the construction of 1D/2D heterostructure and the two-pathway sensing mechanism. It is believed the surface-reconstruction induced orientation-growth method in molten salt can be extended to synthesize other 1D/2D heterostructures for various applications.