Fabrication of a Covalent Organic Framework-Based Heterojunction via Coupling with ZnAgInS Nanosphere with High Photocatalytic Activity.

Covalent organic frameworks (COFs) exhibit visible-light activity for the degradation of organic pollutants. However, the recombination rates of their photoinduced electron-hole pairs are relatively high, limiting their practical application. In this work, we fabricated a 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1) (TpPa-1) COF-based heterojunction through coupling the TpPa-1 COF with a ZnAgInS nanosphere via a facile oil bath heating method. The results show that the prepared heterojunction exhibits outstanding catalytic activity for the degradation of high concentrations the antibiotic tetracycline (TC) and the dye rhodamine B (RhB), which is driven by simulated sunlight. Its degradation rates for RhB and TC were 30× and 18× higher than that of the pure TpPa-1 COF, respectively. The greatly enhanced photocatalytic performances can be ascribed to the formed heterojunction with good band-gap match, which promotes the migration and separation of light-induced electrons and holes and increases both light absorbance and the specific surface area. This study introduces an effective and feasible strategy for improving the photocatalytic performances of COFs via subtly integrating TpPa-1 COFs with a ZnAgInS nanosphere into an organic-inorganic hybrid. The results of the photocatalytic experiments indicate that the fabricated hybrid has a potential application in the highly efficient removal of organic pollutants.

Construction of MOF/COF Hybrids for Boosting Sunlight-Induced Fenton-like Photocatalytic Removal of Organic Pollutants.

In this work, a metal-organic framework (MOF) material of NH2-MIL88B was hybridized with TpPa-1-COF through covalent bonding, and the hybrid was subsequently employed for the degradation of Rhodamine B (RhB) and tetracycline (TC) by simulated sunlight-induced Fenton-like exciting H2O2. The obtained results show that its photocatalytic activity is much better than those of its parent MOF and covalent organic framework (COF). Moreover, it is much higher than that of bare photocatalysis without Fenton-like excitation of H2O2. The high degradation efficiency is ascribed to two factors. One is the formation of hybrid, which promotes charge separation and light absorbance. Another is the Fenton-like excitation of H2O2, which produces more hydroxyl radicals (•OH). This report presents a facile approach to greatly improve the photocatalytic property of MOF materials by the formation of hybrid with COFs and Fenton-like excitation of H2O2.

Fabrication of 2D-2D Heterojunction Catalyst with Covalent Organic Framework (COF) and MoS2 for Highly Efficient Photocatalytic Degradation of Organic Pollutants.

In this work, for the first time, we fabricated a novel covalent organic framework (COF)-based 2D-2D heterojunction composite MoS2/COF by a facile hydrothermal method. The results of photocatalytic degradation of TC and RhB under simulated solar light irradiation showed that the as-prepared composite exhibited outstanding catalytic efficiency compared with pristine COFs and MoS2. The significantly enhanced catalytic efficiency can be ascribed to the formation of 2D-2D heterojunction with a well-matched band position between COF and MoS2, which can effectively restrain the recombination of charge carriers and increase the light absorption as well as the specific surface area. Moreover, the fabricated 2D-2D layered structure can effectively increase the contact area with an intimate interface contact, which greatly facilitates the charge mobility and transfer in the interfaces. This study reveals that artful integration of organic (COFs) and inorganic materials into a single hybrid with a 2D-2D interface is an effective strategy to fabricate highly efficient photocatalysts.

Fabrication of Hierarchical Co9S8@ZnAgInS Heterostructured Cages for Highly Efficient Photocatalytic Hydrogen Generation and Pollutants Degradation.

In the present study, a hierarchical Co9S8@ZnAgInS heterostructural cage was developed for the first time which can photocatalytically produce hydrogen and degrade organic pollutants with high efficiency. First, the Co9S8 dodecahedron was synthesized using a metal-organic framework (MOFs) material, ZIF-67, as a precursor, then two kinds of metal sulfide semiconductors were elaborately integrated into a hierarchical hollow heterostructural cage with coupled heterogeneous shells and 2D nanosheet subunits. The artfully designed hollow heterostructural composite exhibited remarkable photocatalytic activity without using any cocatalysts, with a 9395.3 µmol g-1 h-1 H2 evolution rate and high degradation efficiency for RhB. The significantly enhanced photocatalytic activity can be attributed to the unique architecture and intimate-contact interface between Co9S8 and ZnAgInS, which promote the transfer and separation of the photogenerated charges, increase light absorption, and offer large surface area and active sites. This work presents a new strategy to design highly active semiconductor photocatalysts by using MOF materials as precursors and coupling of metal sulfide semiconductors to form hollow architecture dodecahedron cages with an intimate interface.

Unlocking enhanced photocatalytic power: Donor-acceptor synergy in non-metallic g-C3N4 hollow nanospheres.

Selecting safe, non-toxic, and non-metallic semiconductor materials that facilitate the degradation of pollutants in water stands out as an optimal approach to combat environmental pollution. Herein, graphitic carbon nitride (g-C3N4)-based hollow nanospheres nonmetallic photocatalyst modified with covalent organic framework materials named TpMA, based on 1, 3, 5-trimethylchloroglucuronide (Tp) and melamine (MA), was successfully synthesized (abbreviated as CNTP). The ordered electron donor-acceptor structure inherent in TpMA contributed to enhancing the transport efficiency of photogenerated carriers in CNTP. The CNTP photocatalysts exhibited excellent performance in degrading rhodamine B and tetracycline in visible light, with optimal degradation rates reached more than 90% in 60 and 80 min, respectively, which were 5.3 and 3.0 times higher than those of pure CNNS. The increased photocatalytic efficiency observed in CNTP composites could be traced back to the covalently connection between the two molecules, forming a π-conjugated system that facilitated the separative efficiency of photogenerated electron-hole pairs and intensified the utilization of visible light. This study provided a new means to design and fabricate highly efficient and environmentally friendly non-metallic photocatalytic materials.