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(2) 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.