ABSTRACT
The efficiency of photocatalytic Nitric Oxide(NO) oxidation is limited by the lack of oxygen(O2) active sites and poor charge carrier separation. To address this challenge, we developed a molecular Cobalt Phthalocyanine modified MIL-68(In)-NH2 photocatalyst with a robust Built-in electric field(BIEF). In the 2 % CoPc-MIN sample, the BIEF strength is increased by 3.54 times and 5.83 times compared to pristine CoPc and MIL-68(In)-NH2, respectively. This BIEF facilitates the efficient S-scheme charge transfer, thereby enhancing photogenerated carrier separation. Additionally, the Co-N4(II) sites in CoPc can effectively trap the separated photoexcited electrons in the S-scheme system. In addition, the Co-N4(II) sites can also serve as active sites for O2 adsorption and activation, promoting the generation of superoxide radical (O2-), thereby driving the direct conversion of NO to nitrate(NO3-). Consequently, the 2 % CoPc-MIN sample exhibits a remarkable photocatalytic NO removal efficiency of 79.37 % while effectively suppressing the formation of harmful by-product nitrogen dioxide(NO2) to below 3.5 ppb. This study provides a feasible strategy for designing high-efficiency O2 activation photocatalysts for NO oxidation.
ABSTRACT
The lack of compactness in heterojunction interfaces and poor charge separation is a great challenge in developing high-efficiency heterojunction photocatalysts. Herein, a novel Bi4Ti3O12-BiPO4 heterojunction was successfully prepared for the first time by epitaxial growth of BiPO4 on the surface of Bi4Ti3O12 nanosheets. The optimized Bi4Ti3O12-BiPO4-0.5 increased the NO oxidation efficiency to 73.05%, surpassing pure Bi4Ti3O12 (63.45%) and BiPO4 (8.35%). Experiments and theoretical calculations indicated that the closely contacted heterointerface between BTO and BPO promoted the generation of the built-in electric field, which led to the formation of the Z- scheme transfer pathway for the photogenerated carriers. Therefore, the separation of photogenerated carriers was facilitated while retaining high redox potential, generating more ·O2- and ·OH to participate in NO oxidation. Furthermore, the adsorption of NO and O2 was enhanced by introducing BiPO4, further improving the photocatalytic NO oxidation performance. This work emphasizes the critical role of heterointerface in accelerating charge transfer, providing a basis for the design and construction of tightly contacted heterojunction photocatalysts.
ABSTRACT
White light emitting materials have broad application prospects in fields such as displays, lighting devices, etc., but developing such materials faces considerable challenges. In this study, 1,3,5-tris[4-(pyridine-4-butyl)phenyl]benzene derivative (BTPY) was synthesized and a supramolecular assembly with AIE properties named BTPY@Q[7] was prepared with cucurbit[7]uril (Q[7]). Furthermore, by adding rhodamine 6G (R6G) to it, and controlling its ratio with R6G, a dual-emission white light system (0.33, 0.33) was synthesized and used for white light emitting materials as well as anti-counterfeiting fields. In addition, based on the BTPY@Q[7]-R6G system, a light harvesting system in aqueous phase was constructed, with an energy transfer efficiency (ΦET) of 26.19 % and an antenna effect (AE) of 10.21. Interestingly, the supramolecular self-assembly can also be used as a fluorescent probe, specifically recognize Fe(CN)63- ions in water, with a detection limit of 2.5 × 10-8 M.
