Enhanced photocatalytic activity of mesoporous carbon/C3N4 composite photocatalysts.

HYPOTHESIS: The C3N4 as a cheap and clean photocatalyst shows suitable band gap to splitting water and spectral response. However the poor conductivity of C3N4 limits the photocatalytic hydrogen evolution rate. The combination of C3N4 and high conductivity materials will enhance the separation of photo-generated carriers and thus enhance the photocatalytic activity. As many carbon materials have been tried, the mesoporous carbon should be a good candidate to solve this problem. EXPERIMENTS: A photocatalytic system with C3N4 and mesoporous carbon has been designed to test the photocatalytic performance of both the photocatalytic hydrogen evolution and the photocatalytic degradation of methylene blue. The results of EPR, EIS and PL spectra were given to further understand the photo-generated carrier and its transfer. FINDINGS: The enhancement of the highest hydrogen evolution rate is 48% from 69 to 102 µmol/h by mesoporous carbon/C3N4 sample. The existence of small amount of mesoporous carbon can facilitate the photogenerated carrier separation, thus enhancing the photocatalytic performance. In the meantime, the introduction of mesoporous carbon into C3N4 is beneficial for improving electron delocalization and conduction electrons and increasing the optical absorption.

Sporicidal performance induced by photocatalytic production of organic peroxide under visible light irradiation.

Bacteria that cause serious food poisoning are known to sporulate under conditions of nutrient and water shortage. The resulting spores have much greater resistance to common sterilization methods, such as heating at 100 °C and exposure to various chemical agents. Because such bacteria cannot be inactivated with typical alcohol disinfectants, peroxyacetic acid (PAA) often is used, but PAA is a harmful agent that can seriously damage human health. Furthermore, concentrated hydrogen peroxide, which is also dangerous, must be used to prepare PAA. Thus, the development of a facile and safe sporicidal disinfectant is strongly required. In this study, we have developed an innovative sporicidal disinfection method that employs the combination of an aqueous ethanol solution, visible light irradiation, and a photocatalyst. We successfully produced a sporicidal disinfectant one hundred times as effective as commercially available PAA, while also resolving the hazards and odor problems associated with PAA. The method presented here can potentially be used as a replacement for the general disinfectants employed in the food and health industries.