Tunable Kx-C3N4/ UiO-66-NH2 photocatalyst for selective oxidation of furfural to furoic acid with mediation of Na2CO3

Photocatalytic selective oxidation of furfural is a green, gentle way of preparing furoic acid. Photocatalytic oxidation effectively avoids the problems of difficult separation and high energy consumption in subsequent work-ups caused by the use of homogeneous oxidants. The photocatalytic process suffers from uncontrollable reactive oxygen species, resulting in low selectivity of the target product and excessive oxidation. Therefore, the Kx-C3N4/UiO-66-NH2-Y catalyst was prepared by the mass proportion of UiO-66-NH2 and Kx-C3N4 to form a heterogeneous structure, and the band gap width was adjusted to effectively avoid the formation of non-target strong reactive oxygen species (OH). The results showed that: the aqueous 0.1 mM Na2CO3 solution had an inhibitory effect on the non– target reactive oxygen species at room temperature; when the reaction time was 5 h and K0.1-C3N4/UiO-66-NH2-20, the furoic acid had the highest yield of 70.7, the target reactive oxygen species was confirmed by free radical capture experiments as O2–, and it was postulated that the reaction mechanism for the preparation of furoic acid by selective oxidation of furfural.