Facile Construction of a Hollow In₂S₃/Polymeric Carbon Nitride Heterojunction for Efficient Visible-Light-Driven CO₂ Reduction

Abstract

The development of high-efficiency photocatalysts is of great importance to realize robust solar-driven CO2 conversion; however, the low carrier separation efficiency and poor light absorption ability usually limit the performance of the photocatalysts. Herein, a hollow In2S3/polymeric carbon nitride (IS/CN) heterojunction was prepared via electrostatic self-assembly and in situ sulfidation under solvothermal conditions. The intimate interfacial contact between the IS and CN facilitates the construction of an effective heterojunction, as demonstrated by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The optimized IS/CN-5 sample exhibits a high CO evolution rate of 483.4 μmol g–1 h–1, which is 99 and 6 times as high as that of IS and CN, respectively. The improved charge separation and transfer efficiency, the hollow nanotube structure, and the enhanced CO2 adsorption ability are the reasons for the excellent photocatalytic activity. Besides, a possible photocatalytic mechanism of CO2 reduction by the IS/CN heterojunction was proposed on the basis of the band structures. This work provides an effective and facile strategy to construct hollow semiconductor heterojunctions for photocatalytic applications.

Nitrogen-rich porous polymeric carbon nitride with enhanced photocatalytic activity for synergistic removal of organic and heavy metal pollutants

“…In general, the E CB of an n-type semiconductor is 0–0.2 V more negative than its V fb . 68 Combined with the relationship E NHE / V = E Ag/AgCl / V + 0.197 V, the E CB values of DCN, DCN-S and DCCN-S are approximately −1.12, −0.74 and −1.05 V ( vs. NHE, pH = 7), respectively, in good agreement with those estimated from VB-XPS spectra. On the basis of the above analysis, the band structure alignments are illustrated in Fig.…”

“…According to the formula E NHE / V = Φ + − 4.44 ( E NHE : the potential of the standard hydrogen electrode; Φ = 4.30 eV: the electron work function of the analyzer), the positions of the valence band maximum ( E VB ) for DCN, DCN-S and DCCN-S were estimated to be 1.69, 1.81 and 1.58 V ( vs. NHE, pH = 7), respectively. 68 Based on the relationship between E g and band edge positions, the positions of the conduction band minimum ( E CB ) of DCN, DCN-S and DCCN-S were estimated to be −1.12, −0.74 and −1.06 V ( vs. NHE, pH = 7), respectively.…”

Metal@hollow carbon sphere nanoreactors for sustainable biomass and CO2valorization

“…256,257 Hollow In 2 S 3 /polymeric carbon-nitride (IS/CN) heterojunctions were fabricated by in situ sulfidation under solvothermal conditions and electrostatic self-assembly. 258 Both IS and CN are stimulated by visible light irradiation, producing holes and electrons, with the electrons leaping into the conduction band (CB) and the holes remaining in the valence band (VB). Because of the resulting heterojunction, the photogenerated holes in the VB of the CN are transferred to the VB of the IS, while the photogenerated electrons in the CB of the IS are move to the CB of the CN.…”

Naphthalene Diimide-Based Donor–Acceptor–Donor Small Molecules as Metal-Free Organocatalysts for Photocatalytic CO2 Reaction

“…In 2012, Dong and Zhang first used pristine g-C 3 N 4 as an organic photocatalyst for CO 2 reduction . Since then, several research groups have further improved its photoactivity by incorporating metal components in g-C 3 N 4 . − In addition, POPs have emerged as a promising semiconductor for photocatalytic reactions. In 2019, Dai et al reported two triphenylamine (TPA)-based porous polymers, 2,5-diphenyl-1,3,4-oxadiazole (OXD)-TPA and biphenyl (BP)-TPA; for these two polymers, the electron-withdrawing unit of OXD improved both the light-harvesting capability and charge separation efficiency .…”