Selective Hydrothermal Method To Create Patterned and Photoelectrochemically Effective Pt/WO₃ Interfaces

A hydrothermal method based on the use of hydrogen peroxide is described to grow a homogeneous layer of tungsten oxide (WO3) on a platinum (Pt) film supported on a silicon wafer. WO3 growth is highly selective for Pt when present on silicon in a patterned arrangement, demonstrating that Pt catalyzes decomposition of the WO3 precursor in solution. The obtained Pt/WO3 interface yields high photocurrents of 1.1 mA/cm in photoelectrochemical water splitting when illuminated by a solar simulator. The photocurrents are significantly higher than most previously reported values for hydrothermally grown layers on indium−tin oxide and fluorine−tin oxide glasses. The selective growth method thus provides new options to effectively implement WO3 in photoelectrochemical devices.