Photocatalytic removal of NO by Z-scheme mineral based heterojunction intermediated by carbon quantum dots

A novel photocatalyst integrated with carbon quantum dots (CQDs), SmFeO3 and attapulgite (ATP) clay mineral was synthesized by sol-gel/impregnation method which was successfully applied for NO removal under solar light irradiation. The textual and optical properties of the materials were analyzed by various characterizations. Results indicated the SmFeO3 nanoparticles were uniformed loaded on the ATP support and both coherently interacted with CQDs. The amount of CODs had significant effect on the NO conversion, while 5 wt% incorporation achieved the highest 90% conversion rate. An indirect Z-scheme mechanism was proposed that the CQDs performed as an intermediate between SmFeO3 and ATP for the charge transfer while the high redox potential was maintained. In addition, the ATP fiber showed not only UV-responsive property in Z-scheme structure, but also excellent adsorption effect for gas molecules.