Enhancing the Photodegradation Property of NO through the Construction of a SrTiO3/GQDs/NH2-UiO-66 Heterojunction

To holistically promote oxidative abilities, we construct SrTiO3/GQDs/NH2-UiO-66 (STO/GQDs/NU6, SGN) to degrade nitric oxide (NO) under visible light. By simple electrostatic attraction and a hydrothermal reaction, NU6 nanoparticles are grown evenly on three-dimensional STO microflowers, with graphene quantum dots (GQDs) playing the role of additional electronic transmission bridges as well as type II heterojunction. Introducing conductive materials into the heterojunction solves the problem of a short electron lifetime. The oxygen vacancies (OVs) introduced in STO are conducive to the adsorption of oxygen molecules and the electronic transition and thus generate an active substance. The final product boosts the light-driving removal efficiency of NO (600 ppb). Adjusting the percentage composition of both GQDs and NU6 significantly increases the retention efficiency to 69.0%. This improvement results from the synergistic effect of type II heterojunction construction, the electron transport capacity of GQDs, and the active defect center. Moreover, the resulting compound generates little noxious nitrogen dioxide (NO2) as a byproduct during the catalytic process. Reusability of the SGN system is also verified by transient photocurrent, response measurements, and cycling degradation experiments. This work sheds light on photocatalytic strategies for safe and efficient air purification.