Preparation of a semiconductive compound obtained by the pyrolysis of urea under N2 and the photocatalytic property under visible light irradiation

Preparation and photocatalytic property of a compound prepared from the pyrolysis of urea under N2 atmosphere was investigated. The compounds prepared over 773 K showed photo-absorption below 460 nm and the property of n-type semiconductor. The platinized compounds showed the photocatalytic activity on H2 production from aqueous methanol under the visible light irradiation (shorter than 440 nm). The photocatalytic active phase was confirmed to be graphitic C3N4 (g-C3N4) like phase produced under the pyrolysis of urea above 723 K. The effects of the addition of cyanuric acid and melamine, regarded as the intermediates of the compounds to the photocatalytic activity were examined.