Emerging Concepts in Carbon Nitride Organic Photocatalysis

Abstract

Carbon nitrides encompass a class of transition-metal-free materials possessing numerous advantages such as low cost (few Euros per gram), high chemical stability, broad tunability of redox potentials and optical bandgap, recyclability, and a high absorption coefficient (> 10 5 cm À 1), which make them highly attractive for application in photoredox catalysis. In this Review, we classify carbon nitrides based on their unique properties, structure, and redox potentials. We summarize recently emerging concepts in heterogeneous carbon nitride photocatalysis, with an emphasis on the synthesis of organic compounds: 1) Illumination-Driven Electron Accumulation in Semiconductors and Exploitation (IDEASE); 2) singlet-triplet intersystem crossing in carbon nitride excited states and related energy transfer; 3) architectures of flow photoreactors; and 4) dual metal/carbon nitride photocatalysis. The objective of this Review is to provide a detailed overview regarding innovative research in carbon nitride photocatalysis focusing on these topics.

Visible-Light-Driven Photocatalytic Water Disinfection Toward Escherichia coli by Nanowired g-C3N4 Film

“…As the superoxide anion (•O 2 − ) is an active intermediate in the production of H 2 O 2 , the more O 2 − is produced, the more H 2 O 2 will be generated. Based on these results we can then confirm that the disinfection mechanism occurs via the generation of superoxide and water peroxide, and thus is related to the strong oxidation properties of g-C 3 N 4 (Mazzanti and Savateev, 2020).…”

Structure/Property Control in Photocatalytic Organic Semiconductor Nanocrystals

“…This is why the bandgap in molecular crystals is comparatively small, typically in the 1.5–3.5 eV range. Photocatlytic OSNs show a marked diversity, and can be generally categorized into the following families ( Figure ): small‐molecular phthalocyanines (PCs), [ 16 ] porphyrins, [ 17 ] perylene diimides (PDIs), [ 18 ] perylene monoimides (PMIs), [ 19 ] fullerenes (C 60 , C 70 ), and polymeric graphitic carbon nitride (g‐C 3 N 4 ), [ 20 ] polypyrroles (PPYs), [ 21 ] polythiophenes (PTHs), [ 22 ] polypyridine (PPyDs), [ 23 ] polyanilines (PANIs), [ 24 ] polyimides (PIs) [ 25 ] etc. Crystalline porous polymers are an important addition to the family of polymeric photocatalysts, encompassing a broad range of systems from metal‐organic frameworks (MOFs) [ 6c ] to covalent organic frameworks (COFs).…”

Photoredox catalysis in nickel-catalyzed C–H functionalization

“…The authors proposed a plausible catalytic cycle to account for the mode of action of this cascade arylation protocol (Figure 10) [73]. In the photocatalytic cycle, the SET event be- The König group discovered that the arylation of α-amino C(sp 3 )-H bonds could be realized with aryl halides using mesoporous graphitic carbon nitride (mpg-CN) [74][75][76] as a heterogeneous organic semiconductor photocatalyst in combination with nickel catalysis [77]. Here, the catalytic system consisting of NiBr 2 •glyme, 2,2′-bipyridine, 2,6-lutidine, and mpg-CN under blue light irradiation at ambient temperature was found to be optimal to furnish the desired cross-coupled products 37 in satisfactory yields.…”