Controlled Surface Modification Of Various Substrates With SnO₂Nanoparticles And Its Gas-sensing Properties

Surface modification of various substrates with SnO2nanoparticles are expected tohave wide applications in the fields of gas sensing, photocatalysis. However, the previousroutes are still a little complex, costly, and may not satisfy various applicationrequirements. Therefore, it is supposed to be meaningful to find a facile way to load SnO2nanoparticles on any desired substrates.In this work, we describe a simple, cost-effective approach for surface modificationof various substrates with SnO2nanoparticles by controlled hydrolysis, which is notconfined on specific chemical states of the surface. Specifically, these SnO2nanoparticleswere loaded onto the surfaces of carbon-based materials (graphene and CNTs), ioniccrystals (tin sulfide), polymer materials (silk fiber) and biological materials (yeast)withuniform distribution, despite the great differences in surface chemistries. The XRD, SEM，EDX，XPS and TEM results reveal that spherical SnO2particles spread evenly over all thesubstrate materials, and the diameters of the particles fell into a small range under5nm.Moreover, these SnO2nanoparticles were structurally of a uniform single crystal naturewith high crystallinity and were tightly integrated to the surface. The consistent anduniform surface modification with SnO2nanoparticles can be applied on various desiredsubstrates, which is not confined on specific chemical reactions or interactions with thesurface state. Moreover, the formation mechanism of the SnO2nanoparticles has beendiscussed, confirming that the process described can be easily implemented and adapted toother systems.The application of this method has also been studied. This method can also be used topreserve the structure of nanomaterials. In our work, SnO2/CNTs nanocomposites werescreen printed on the surface of coplanar sensor, and nanowire-like SnO2network wasdirectly obtained by structure replication from CNTs after thermal treatment. Theas-prepared porous nanowire-like SnO2network exhibited a good response and reversibility to some organic gases, such as formaldehyde and alcohols. The nanowire-likeSnO2network is a very promising gas-sensing material due to its large surface area andporous structures with a less agglomerated configuration.It is prospective that our route for surface modification of various substrates withSnO2nanoparticles will have important applications, including their use to sensitizegas-sensitive materials and photocatalytic materials. In addition, the route may also havepotential for some biochemical uses.