Photooxidation of biomass for sustainable chemicals and hydrogen production on graphitic carbon nitride-based materials: A comprehensive review
Mohammed Ismael, Qiaoyan Shang, Jun Yue, Michael Wark
Abstract
Photocatalytic biomass conversion is commonly recognized as one of the most favorable procedures to fabricate valuable chemicals as well as carbon-free hydrogen energy. Developing novel photocatalysts is necessary to achieve significant improvement in the target product selectivity and yield. Graphitic carbon nitride (g-C3N4) is a potential material for the photooxidation of biomass due to its intriguing physicochemical, electronic, and optical properties. In this review, we summarized the latest development in the photooxidation of lignocellulosic biomass and biomass-derived substrates such as 5-hydroxymethylfurfural (5-HMF) and sugars over g-C3N4 to produce highly value-added chemicals. This review also sheds light on the current advancement in hydrogen evolution efficiency over g-C3N4-based photocatalytic material coupled with conversion of biomass and its substrates. Herein, the properties, synthesis, morphological nanostructures, characterization, modification techniques, and photocatalytic applications of g-C3N4 photocatalysts were highlighted. Various methods for enhancing its stability, and efficiency for commercialization utilization were emphasized. Then, the process intensification aspects for the photocatalytic process over g-C3N4-based photocatalysts in continuous flow microreactors are discussed. Finally, we discussed the perspectives, challenges, and knowledge gap in the future directions for native lignocellulose biomass photocatalytic conversion and upcoming difficulties to improve the profitability and sustainability of photocatalytic hydrogen production by using metal-free g-C3N4-based photocatalytic materials.