Perylenetetracarboxylic diimide modified Zn 0.7 Cd 0.3 S hybrid photocatalyst for efficient hydrogen production from water under visible light irradiation

Recent Advances and Insights in Designing ZnxCd1-xS-Based Photocatalysts for Hydrogen Production and Synergistic Selective Oxidation to Value-Added Chemical Production

Combining the hydrogen (H2) extraction process and organic oxidation synthesis in photooxidation-reduction reactions mediated by semiconductors is a desirable strategy because rich chemicals are evolved as byproducts along with hydrogen in trifling conditions upon irradiation, which is the only effort. The bifunctional photocatalytic strategy facilitates the feasible formation of a C═O/C─C bond from a large number of compounds containing a X-H (X = C, O) bond; therefore, the production of H2 can be easily realized without support from third agents like chemical substances, thus providing an eco-friendly and appealing organic synthesis strategy. Among the widely studied semiconductor nanomaterials, ZnxCd1-xS has been continuously studied and explored by researchers over the years, and it has attracted much consideration owing to its unique advantages such as adjustable band edge position, rich elemental composition, excellent photoelectric properties, and ability to respond to visible light. Therefore, nanostructures based on ZnxCd1-xS have been widely studied as a feasible way to efficiently prepare hydrogen energy and selectively oxidize it into high-value fine chemicals. In this Review, first, the crystal and energy band structures of ZnxCd1-xS, the model of twin nanocrystals, the photogenerated charge separation mechanism of the ZB-WZ-ZB homojunction with crisscross bands, and the Volmer-Weber growth mechanism of ZnxCd1-xS are described. Second, the morphology, structure, modification, synthesis, and vacancy engineering of ZnxCd1-xS are surveyed, summarized, and discussed. Then, the research progress in ZnxCd1-xS-based photocatalysis in photocatalytic hydrogen extraction (PHE) technology, the mechanism of PHE, organic substance (benzyl alcohol, methanol, etc.) dehydrogenation, the factors affecting the efficiency of photocatalytic discerning oxidation of organic derivatives, and selective C-H activation and C-C coupling for synergistic efficient dehydrogenation of photocatalysts are described. Conclusively, the challenges in the applicability of ZnxCd1-xS-based photocatalysts are addressed for further research development along this line.

Facile Construction of Intramolecular g-CN-PTCDA Donor-Acceptor System for Efficient CO2 Photoreduction

Due to the different electron affinity, the construction of a donor-acceptor (DA) system in the graphitic carbon nitride (g-CN) matrix is an attractive tactic to accelerate photo-induced electron-holes separation, and then further elevate its photocatalytic performance. In this work, perylene tetracarboxylic dianhydride (PTCDA) with magnificent electron affinity and excellent thermal stability was chosen to copolymerize with urea via facile one-pot thermal copolymerization to fabricate g-CN-PTCDA equipped with DA structures. The specific surface area of g-CN-PTCDA would be enlarged and the visible light absorption range would be broadened simultaneously when adopting this copolymerization strategy. A series of characterizations such as electron paramagnetic resonance (EPR), steady and transient photoluminescence spectra (PL), electrochemical impedance spectroscopy (EIS), and photocurrent tests combined with computational simulation confirmed the charge separation and transfer efficiency dramatically improved due to the DA structures construction. When 0.25% wt PTCDA was introduced, the CO evolution rate was nearly 23 times than that of pristine g-CN. The CO evolution rate could reach up to 87.2 μmol g−1 h−1 when certain Co2+ was added as co-catalytic centers. Meanwhile, g-CN-1 mg PTCDA-Co exhibited excellent long-term stability and recyclability as a heterogeneous photocatalyst. This research may shed light on designing more effective DA structures for solar-to-energy conversion by CO2 reduction.

Review on application of perylene diimide (PDI)-based materials in environment: Pollutant detection and degradation

Environment pollution is getting serious and various poisonous contaminants with chemical durability, biotoxicity and bioaccumulation have been widespreadly discovered in municipal wastewaters and surface water. The detection and removal of pollutants show great significance for the protection of human health and other organisms. Due to its distinctive physical and chemical properties, perylene diimide (PDI) has received widespread attention from different research fields, especially in the area of environment. In this review, a comprehensive summary of the development of PDI-based materials in fluorescence detection and advanced oxidation technology for environment was introduced. Firstly, we chiefly presented the recent progress about the synthesis of PDI and PDI-based nanomaterials. Then, their application in fluorescence detection for environment was presented and categorized, principally including the detection of heavy metal ions, harmful anions and organic contaminants in the environment. In addition, the application of PDI and PDI-based materials in different advanced oxidation technologies for environment, such as photocatalysis, photoelectrocatalysis, Fenton and Fenton-like reaction and persulfate activation, was also summarized. At last, the challenges and future prospects of PDI-based materials in environmental applications were discussed. This review focuses on presenting the practical applications of PDI and PDI-based materials as fluorescent probes or catalysts (especially photocatalysts) in the detection of hazardous substances or catalytic elimination of organic contaminants. The contents are aimed at supplying the researchers with a deeper understanding of PDI and PDI-based materials and encouraging their further development in environmental applications.