Functional B@mCN-assisted photocatalytic oxidation of biomass-derived pentoses and hexoses to lactic acid

Abstract

The integration of biorefining and photocatalysis is the most promising approach to enable green and efficient synthesis of biomass-based high value chemicals. Herein, a novel and functional carbon nitride photocatalyst was developed to achieve the production of lactic acid under visible-light irradiation. The doping of boron (B) and oxygen (O) atoms in the catalyst (B@mCN-Y) not only reduced the bandgaps, but also improved the separation efficiency of surface photoinduced charge carriers, resulting in an enhanced photocatalytic activity of B@mCN-Y. Furthermore, the catalyst exhibited excellent activity for different biomass-based monosaccharides, and the highest yield was 92.7%. Various oxidative active species of h⁺, ¹O₂, ˙O₂⁻ and ˙OH all benefit the synthesis of lactic acid, while the effect of h⁺ is superior to that of the others. The catalyst is also highly stable and recyclable, and the system for producing lactic acid has potential for amplification. The yield and conversion of a one-thousand-fold scale-up experiment retained 68.6% and 89.0% of the values of the one time experiment. This work promotes the development of photocatalytic biomass refining.