Electrochemical synthesis and characterization of tungsten oxide catalysts for photoelectrochemical water splitting

In the present paper, synthesis of porous tungsten oxide via anodization in sulfate-fluoride electrolytes at different voltages and process durations, followed by thermal treatment at 500 C, is reported. The porosity of the obtained oxides is estimated by re-anodization in a non-dissolving electrolyte. Electronic conductivity is assessed using voltammetric measurements. Electronic properties of the oxide are determined using highfrequency capacitance-potential measurements. The results are interpreted by contemporary models for the semiconductor/electrolyte junction. Spectral characteristics of modulated photocurrent are also registered to estimate the optical band gap of oxides. The photo-induced carrier dynamics in the oxides is assessed by intensity modulated photocurrent spectroscopy (IMPS). Based on the multi-method characterization, conclusions are drawn on the photo-absorbing and photo-catalytic properties of the oxides depending on anodization conditions.