Applied Surface Science, Vol.450, 9-20, 2018
Pt-decorated SnO2 nanotubes prepared directly on a conducting substrate and their application in solar energy conversion using a solid polymer electrolyte
We report the electrostatic decoration of Pt nanoparticles on SnO2 nanotubes (ST) directly prepared on a conducting substrate and high electrocatalytic activities of the resulting materials. A pre-coating of poly (vinyl acetate) (PVAc) is the key for the direct uniform deposition of the ST, which serves dual functions as a fast electron transport path as well as a physical support for Pt nanoparticles. The self-assembly of Pt nanoparticles on the ST is based on electrostatic interaction between the Pt cations and negatively charged ST surface. A dip-coating method leads to homogeneous decoration of well-connected Pt nanoparticles with a larger surface area. Solar energy conversion devices with a solid polymer electrolyte are fabricated using Pt on ST as the electrocatalyst for the reduction of I-3 to I. The Pt dip-coated ST shows a photovoltaic efficiency of 5.07%, which is higher than those of Pt spin-coated ST (4.88%) and Pt spincoated on the substrate without ST (4.59%). An increase in the Pt concentration leads to further improvement in the efficiency up to 5.51%, which is a moderate value for solid electrolyte devices. The improved performance is attributed to the decreased electron transfer resistance and increased surface area of the electrode. (C) 2018 Elsevier B.V. All rights reserved.