Search

Summary: Conjugated monomer 2,6‐dimethylindole (DMI) was integrated into the triazine framework of polymeric carbon nitride (PCN) via molecular engineering. As‐prepared samples were utilized for photocatalytic evolution of hydrogen (H2) through water splitting and photodegradation of RhB dye under visible light. The integration of this monomer DMI has been dominated within the internal framework of PCN and operated as a substitution reaction membrane, retarding an appropriate control and promote the charge density in π‐electron conjugated system. It also promotes the charge transferring and separation to elevate the photocatalytic activity of PCN under visible light. The HER for pure PCN was found as 77.9 μmol/h, while for PCN‐DMI18.0 was predicted at 701.2 μmol/h, which is exclusively output approximately nine times higher than that of pure PCN respectively. Besides, the pseudo‐order kinetic constant of PCN‐DMI18.0 degradation of RhB was multiple times higher when contrasted to pristine PCN. [ABSTRACT FROM AUTHOR]

Summary: Integration by conventional polymerization of different organic monomers with carbon nitride (CN) is a scalding topic and a simple one‐pot process. To change the electronic structure, chemical composition, and photocatalytic activity of CN, we report the deficient quinone ring monomer here. Thermal copolymerization of urea with 2,6‐diaminoantandantquinone (DQ) monomer is an efficient synthesis of a sequence of modified CN photocatalysts. Results show that the optical absorption capacity is improved by modulating the quinone ring in the CN framework, improving its charge transfer and separation of photogenerated electron and holes. The modified CN shows a notable improvement in the photocatalytic activity of overall water splitting, such as hydrogen evolution rate (HER) and oxygen evolution rate (OER). The co‐polymerized CN‐DQ5.0 displays a remarkable activity of 520.8 μmol/h of H2 evolution and 6.8 μmol/h of O2 evolution, which is around 8 times and 4.5 times greater than CN. The universal copolymerization by a small, optimized amount of monomer DQ explores a remarkable improvement in the photocatalytic activity. Novelty Statement: We manifested the process of molecular doping with carbon nitride (CN) semiconductor for utilization of solar heat radiation into chemical energy under sunlight perspective.Here, we suggest a novel nanoscopic organic‐conjugated heterocyclic monomer 2,6‐diaminoantandantquinone (DQ) monomer as a demonstrator within CN that boost the photocatalytic properties.An identifiable undulation occurred in the surface area, electronic structure, calculated band gap, and chemical composition analysis of CN and also improved its electronic generation process under visible light radiance.The superior photocatalyst stimulated a tremendous photocatalytic activity of water reduction and water oxidation as enhanced catalytic performances compared of pristine sample, respectively. [ABSTRACT FROM AUTHOR]

The systematic alteration of a carbon nitride unit (CNU) for visible light photocatalytic water splitting is a promising research subject owing to the increasingly serious energy and environmental complications. Herein, the conjugated monomer 3,6‐dibromopyridazine (DBP) is integrated within polymeric carbon nitride (PCN named as CNU = carbon nitride containing urea precursor) via thermal condensation, which is designated as CNU‐DBP. These samples are used for the first time in the photocatalytic conversion of CO2 reduction and hydrogen (H2) evolution through water splitting. Such integration intimidates the electron density, promoting charge transfer separation and elevating the photocatalytic activity of CNU under visible light illumination. The superior sample such as CNU‐DBP9.0 after 4 h of photooxidation generates 65.7 μmol of CO and 17.3 μmol of H2 of the reaction system, emphasizing the highest photocatalytic activity. The H2 evolution rate (HER) for pristine CNU is found as 11.9 μmol h−1, whereas for CNU‐DBP9.0 it is estimated at 178.2 μmol h−1 with 15 times greater activity. This process predicts a significant diversion in the specific area, bandgap, and chemical composition and promotes the efficient separation of photogenerated charge carriers from the ground state to the excited state of CNU, thereby considering it a best candidate for the photoreduction of CO2 source and water splitting into H2. [ABSTRACT FROM AUTHOR]

The modification of carbon nitride (CN) for visible light photocatalytic CO2 reduction is an important issue to explore in the context of energy and environmental challenges. The current work describes the fabrication of a butterfly-shaped photocatalyst derived from a heterojunction between the electron-rich organic monomer 2,5-dibromothiophene (TP) and a CN framework via copolymerization (UCN-TP). The successful incorporation of TP within CN means that it acts as a nucleophilic spare entity that provides electron solidity (π-conjugation) via charge allocation and increases the photocatalytic activity of CN (under visible light illumination). Density functional theory (DFT) data provide additional information on the amalgamation of TP inside CN and the reduced band gap. The best sample UCN-TP0.06 generated 68.18 μmole of CO and 18.52 μmole of H2 by photoreduction, demonstrating the highest photocatalytic activity. Moreover, this remarkable modification of the chemical configuration, band gap and surface area encouraged the good detachment of light-produced photons, thereby rendering it the best candidate for the photoreduction of CO2. [ABSTRACT FROM AUTHOR]