Selective and efficient cleavage of lignin model compound into value-added aromatic chemicals with CuFe2O4 nanoparticles decorated on partially reduced graphene oxides via sunlight-assisted heterogeneous Fenton processes

Abstract

Abstract We developed a unique photocatalyst, CuFe2O4 nanoparticles decorated on partially reduced graphene oxides, to selectively and efficiently cleave lignin model compounds into value-added aromatic chemicals via a sun-light assisted heterogeneous Fenton process. Through proper design of the photocatalyst composition and reaction conditions, controlled oxidative cleavage of the lignin model compound was achieved to produce high-value aromatic chemicals, guaiacol and 2‑methoxy‑4-propylphenol, in high yields, instead of complete mineralization of the lignin model compound. The CuFe2O4 nanoparticles effectively catalyze the generation of highly oxidative free radicals from the oxidant, H2O2, for β-O-4 bond cleavage. The partially reduced graphene oxides serve as the large size support to accommodate and immobilize the CuFe2O4 nanoparticles for easy recycling of the catalyst, to attract the lignin model compounds through π–π stacking and hydrogen bonding for efficient cleaving reaction, and to accelerate transport of photo-induced electrons for better charge separation and thus higher photocatalytic activities. At optimal conditions, yields of 72.6% and 52.5% were achieved for guaiacol and 2‑methoxy‑4-propylpheno, respectively in 60 min at room temperature and under ambient pressures.