Photocatalysis and photoelectrochemical glucose oxidation on Bi2WO6: Conditions for the concomitant H2 production

Abstract

Glucose solar light photoinduced oxidation on Bi2WO6 and the chemical kinetics conditions for concurrent photoelectrochemical H2 production are reported. The results show that the conversion of this organic compound is determined by their surface concentration according to the Langmuir-Hinshelwood mechanism. The performance of Bi2WO6 powder for the photocatalytic oxidation of glucose is higher than that observed with TiO2-based materials. Glucose degradation and mineralization rates are similar; therefore, stable intermediates are not formed during glucose oxidation. Photoluminescence studies indicate that glucose promotes electron injection into the valence band of semiconductor. The initial glucose concentration in combination with the electrode potential used, determines the H2 production. In fact, electrode potential of 0.9 V vs. SHE and 60 ppm of glucose defines kobs values equal to kK with maximum H2 evolution rate: 3.05 μmol h−1 cm−2. This value arises from the transformation of the 97% of the Faradaic current measured. The phenomenological conditions for renewable energy applications have been envisaged.