Ionothermal Synthesis of Triazine–Heptazine‐Based Copolymers with Apparent Quantum Yields of 60 % at 420 nm for Solar Hydrogen Production from “Sea Water”

Abstract

Polymeric carbon nitride (PCN), in either triazine or heptazine form, has been regarded as a promising metal-free, environmentally benign, and sustainable photocatalyst for solar hydrogen production. However, PCN in most cases only exhibits moderate activity owing to its inherent properties, such as rapid charge carrier recombination. Herein we present a triazine-heptazine copolymer synthesized by simple post-calcination of PCN in eutectic salts, that is, NaCl/KCl, to modulate the polymerization process and optimize the structure. The construction of an internal triazine-heptazine donor-acceptor (D-A) heterostructure was affirmed to significantly accelerate interface charge transfer (CT) and thus boost the photocatalytic activity (AQY=60 % at 420 nm). This study highlights the construction of intermolecular D-A copolymers in NaCl/KCl molten salts with higher melting points but in the absence of lithium to modulate the chemical structure and properties of PCN.

Direct Observation of Dynamic Bond Evolution in Single‐Atom Pt/C3N4 Catalysts

“…Furthermore, high‐resolution transmission electron microscopy (HR‐TEM, Figure B) was employed to examine Pt distribution on C 3 N 4 nanorods. The inset HR‐TEM image shows a lattice spacing of 0.94 nm, corresponding to the (100) plane of an in‐planar arrangement of nitrogen‐linked heptazine units . Specifically, no obvious Pt particle or cluster was observed, thus suggesting highly uniform Pt loading on the C 3 N 4 .…”

Polydopamine and Barbituric Acid Co‐Modified Carbon Nitride Nanospheres for Highly Active and Selective Photocatalytic CO2 Reduction

“…Particularly, copolymerization with monomers is an effective way to tailor the structure and properties of carbon nitride at molecular scale , . The copolymerization strategy can always generate more grain boundary defects and improve the crystallinity of carbon nitride, which is beneficial to promote the separation and fast transfer of photogenerated carriers compared to amorphous counterparts , . Nevertheless, the photocatalytic activity and selectivity of g‐C 3 N 4 is still unsatisfactory for practical applications.…”

Recent Advances in Visible‐Light‐Driven Hydrogen Evolution from Water using Polymer Photocatalysts

“…In particular, DA−HM1 showed significantly enhanced photocatalytic activity because of extended spectral absorption and high efficiency in charge separation and photoexcited carrier transfer. Very recently, they have also reported triazine−heptazine copolymers synthesized through simple post calcination of polymeric carbon nitride (PCN) in eutectic salts (NaCl/KCl) to accelerate the polymerization process and tailored the structures, morphologies, and electronic and optical properties of the materials . It was confirmed that these D‐A heterostructures significantly accelerate interface CT and thus enhance photocatalytic activity (CN−NaK, AQY=60 % at 420 nm).…”