Overview on photoreforming of biomass aqueous solutions to generate H2 in the presence of g-C3N4 based materials

Abstract

Photoreforming (PR) of biomass can be considered a viable technology under mild experimental conditions to produce hydrogen with high reaction rate using compounds from renewable resources and waste materials. The application of biomass PR gives rise to both hydrogen generation and biomass waste valorization. The process could be scaled up to obtain hydrogen under solar irradiation and in recent years, research on photocatalysts based on polymeric carbon nitride (g-C3N4) has been widely considered. The non-metallic based carbon nitride materials are economical and (photo)stable polymer semiconductors, and their physicochemical surface and electronic properties are optimal for obtaining H2 which is considered an essential gas from the point of view of environmental sustainability. Some hindrances related to their structure, as the low absorption of visible light and the relatively high recombination rate of electron-hole pairs limit the performance, therefore it is necessary to improve their activity and the yield of the process by modifying them in various ways. In this context various types of approaches have been proposed, such as for example their coupling with other semiconductors to form composite materials. The current mini-review aims to overview the PR field reporting some of the most interesting papers devoted to understand the role of g-C3N4 in biomass PR. Information on many physico-chemical aspects related to the performance of the process and possible ways to obtain better results than those present up to now in the literature will be reported.