Construction of a metal-free photocatalyst via encapsulation of 1,2,3,5-tetrakis(carbazole-9-yl)-4,6-dicyanobenzene in a carboxymethylcellulose-based hydrogel for photocatalytic lactic acid production

• Published in: Green chemistry : an international journal and green chemistry resource : GC 2023-01, Vol.25 (2), p.736-745
• Main Authors: Sun, Shaofei, Sun, Shaochao, Liu, Kangning, Xiao, Ling-Ping, Ma, Jiliang, Sun, Runcang
• Format: Article
• Language: English
• Subjects: Acid production; Biomass; Carbazole; Carbazoles; Carboxymethylcellulose; Catalytic activity; Conversion; Electromagnetic absorption; Encapsulation; Green chemistry; Hydrogels; Industrial applications; Lactic acid; Photocatalysis; Photocatalysts; Solar energy; Synergistic effect
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/D2GC04336J

The efficient application of solar energy to realize photocatalytic biomass conversion to value-added chemicals is of significance. Herein, we propose a novel metal-free photocatalyst (4CzIPN@CMC-HG), which was prepared by encapsulating 1,2,3,5-tetrakis(carbazole-9-yl)-4,6-dicyanobenzene (4CzIPN) in a carboxymethylcellulose-based hydrogel (CMC-HG) using a one-step thermal polymerization strategy. 4CzIPN@CMC-HG has an efficient photon-to-electron conversion rate, excellent visible light absorption, fast photogenerated carrier migration/separation, and high photocatalytic activity, with 90.7% yield of lactic acid (LA) and 100.0% conversion of xylose due to the synergistic effects between 4CzIPN and CMC-HG. 4CzIPN@CMC-HG showed remarkable universality and excellent stability, and the 1000-times amplification system indicated that this system has a potential industrial application in LA production. Furthermore, trapping experiments indicated that ˙OH, h + , 1 O 2 , and ˙O 2 − contributed to LA synthesis, with ˙O 2 − taking a leading role. These results showed the promising application prospects of metal-free photocatalysts in the photocatalytic biomass conversion to value-added chemicals.