Unravelling intramolecular charge transfer in donor–acceptor structured g-C₃N₄ for superior photocatalytic hydrogen evolution

Abstract

The photocatalytic performance of donor–acceptor structured g-C3N4 was enhanced by up to 3.83-fold due to the accelerated intramolecular charge transfer.

Promoting intramolecular charge transfer of graphitic carbon nitride by donor–acceptor modulation for visible‐light photocatalytic H2 evolution

“…The corresponding intensity of the CNDM x signal is much higher than that of UCN, which reveals CNDM x has a much higher concentration of unpaired electrons and a stronger p–π‐conjugated delocalization effect owing to the introduced π‐conjugated DM. [ 39 ] Combined with the results of solid‐state 13 C NMR and XPS spectra, one can conclude that the intensive p–π‐conjugated delocalization effect in CNDM 200 promotes the formation of IEF. The more unpaired electrons and enhanced delocalized effect in CNDM x further promote the ICT process and separation of photoinduced electrons and holes.…”

“…[ 47 ] Besides, the bands around 1700–1100 cm −1 and 806 cm −1 are ascribed to the stretching and breathing vibration modes (out‐of‐plane bending) of aromatic 3‐ s‐ triazine heterocycles, respectively. [ 39 ] Clearly, the peak around 3072 cm −1 associated with the stretching vibration mode of aromatic C–H (combined with FTIR spectra of DM molecule; Figure 1D) reveals the incorporation of DM into CNDM x . Furthermore, the strong H–O ads /N–H/N–H…N absorption band of CNDM 200 indicates its robust adsorption ability of the H 2 O molecules by hydrogen‐bond interaction, promoting the PHE process.…”

“…Recently, inspired by visible-light PHE of donoracceptor (D-A)-based conjugated copolymers, [29,30] the researches to date have also focused on D-A-based g-C 3 N 4 -conjugated copolymers (D-A g-C 3 N 4 ). [31][32][33][34][35][36][37][38][39] The internal electric field (IEF) can be formed within the entire D-A g-C 3 N 4 bulk phase by introducing small organic molecules as electron donors (D) or electron acceptors (A), which provides a driving force for intramolecular charge transfer (ICT) in an excited state. [30,40] The generation mechanism of IEF in an organic system, principally depends on the inductive effect (short-range interaction) and π-conjugated delocalized effect (long-range interaction).…”

Molecular engineering of g-C3N4 with spatial charge separation for enhancing photocatalytic performances

“…26 Zhang et al prepared aromatic ring-grafted CN by calcining of urea and enzoic acid, naphthoic acid, or anthroic acid, which led to a 3.5-fold improvement in H 2 evolution. 27 The fabrication of CN-based polymers with intramolecular donor-acceptor (D-A) groups is also a useful method for redistributing electrons for efficient charge carrier separation. 20,[27][28][29] Liu et al prepared an ultrathin CN-benzoyl isothiocyanate D-A conjugated copolymer with expanded light absorption properties, high charge carrier separation, and enhanced H 2 production activity.…”

Constructing g-C3N4/Cd1−xZnxS-Based Heterostructures for Efficient Hydrogen Production under Visible Light

“…For example, this can be performed by creating heterojunctions that ensure the transfer of charge carriers across the semiconductor 1/semiconductor 2 interface [13][14][15]. For these systems, multiple pathways for photoinduced electron and hole migration may be realized [16,17]. Recently, composite systems such as CdS/g-C 3 N 4 [14], TiO 2 /g-C 3 N 4 [15], BiVO 4 /g-C 3 N 4 [18], and CoO/g-C 3 N 4 [19] have been proposed for photocatalytic hydrogen production.…”