No abstract

We report the sol-gel synthesis of a CuWO 4 (E g $ 2.0-2.15 eV) thin film loaded with Ag nanowires. The incorporation of Ag nanowires into the semiconductor matrix significantly improves the performance of CuWO 4 as a photoanode for use in photochemical water splitting (PEC). Here, we have developed a planar electrode to test the photoactivity of the catalyst using standard electrochemical procedures under simulated solar light. The sol-gel synthesis of CuWO 4 is modified such that we add Ag nanowires during sol aging. We demonstrate that there is negligible change to the CuWO 4 matrix microstructure, morphology or crystal structure. When we compare the pristine CuWO 4 to the material with Ag nanowires embedded in the CuWO 4 matrix there is a fourfold improvement of photocurrent at 1.23 V vs.NHE to ca. 1.5 mA cm À2 (pH 9) under simulated AM1.5G illumination. This photocurrent is very competitive against more well developed photoanode structures when consideration for surface area is allowed. The Ag nanowires increase carrier mobility film enabling a sufficiently thick sample of catalyst, measured at 750 nm, to effectively harvest incident light. The addition of the Ag nanowires removes the plateau region found for CuWO 4 further indicating that there is a good flow of carriers to the surface of the catalyst, a significant improvement as carrier mobility has been shown to be low in CuWO 4 . The Faradaic efficiency of the catalyst was measured at 31%. Our flat band potential is found to be 0 vs. NHE.The ability to make a highly photoactive catalyst using a simple chemical process opens up opportunities in a wide range of areas that focus on PEC and other light harvesting processes.Cite this: J. Mater. Chem. A, 2015, 3, 9638

Glazing employing electrochromic materials can change their optical characteristics of transparency and absorption of solar radiation according to users' needs by simultaneously reducing visible light and NIR transmission through the window. However, spectral selectivity has been becoming a key requirement in smart dynamic windows as it permits maximizing both visual and thermal comfort while minimizing energy consumption for heating, cooling, and lighting. Herein, a dual band electrochromic system is presented, which consists of an engineered nanocomposite electrode capable of advantageously combining the broad band plasmonic response of nanocrystalline indium-tin-oxide with high optical contrast of polyaniline. Their synergistical spectroelectrochemical features make possible the implementation of a four-state tunable electrochromic system (here referred to as "plasmochromic"), which permits selectively regulating optical transmittance in the visible and near-infrared range and exhibits excellent spectral selectivity (the ratio between visible light transmittance (T LUM ) and solar transmittance (T SOL ) can be tuned from 0.67 to 1.61) across a potentials window of only 1.2 V.