Tailoring Advanced N‐Defective and S‐Doped g‐C₃N₄ for Photocatalytic H₂ Evolution

Abstract

Although challenges remain, synergistic adjusting various microstructures and photo/electrochemical parameters of graphitic carbon nitride (g‐C3N4) in photocatalytic hydrogen evolution reaction (HER) are the keys to alleviating the energy crisis and environmental pollution. In this work, a novel nitrogen‐defective and sulfur‐doped g‐C3N4 (S‐g‐C3N4‐D) is designed elaborately. Subsequent physical and chemical characterization proved that the developed S‐g‐C3N4‐D not only displays well‐defined 2D lamellar morphology with a large porosity and a high specific surface area but also has an efficient light utilization and carriers‐separation and transfer. Moreover, the calculated optimal Gibbs free energy of adsorbed hydrogen (ΔGH*) for S‐g‐C3N4‐D at the S active sites is close to zero (≈0.24 eV) on the basis of first‐principle density functional theory (DFT). Accordingly, the developed S‐g‐C3N4‐D catalyst shows a high H2 evolution rate of 5651.5 µmol g−1 h−1. Both DFT calculations and experimental results reveal that a memorable defective g‐C3N4/S‐doped g‐C3N4 step‐scheme heterojunction is constructed between S‐doped domains and N‐defective domains in the structural configuration of S‐g‐C3N4‐D. This work exhibits a significant guidance for the design and fabrication of high‐efficiency photocatalysts.

Sulfur-doped g-C3N4 photocatalyst for significantly steered visible light photocatalytic H2 evolution from water splitting

“…The strongest peak was observed at 398.6 eV, corresponding to the sp 2 -hybridized pyridinic-N species in the triazine rings (CN–C). 21,56 The peaks at 399.8 and 401.2 eV are ascribed to the tertiary nitrogen (N–C 3 ) and terminal amino groups (C–N–H) of the general g-C 3 N 4 structure, respectively. 26,41,57 The weak peak appearing at 404.3 eV is associated with π-excitations.…”

“…5d). The photocurrent of S-CN-7 is nearly 2.3 times higher than that of pristine g-C 3 N 4 , which shows more favorable photocatalytic kinetic properties for photocatalytic H 2 evolution, 21 because sulfur doping shortens the layer spacing of S-CN-7, which accelerates the charge transfer between interlayers, and promotes the excitons to migrate from the interior to the interface and inhibits recombination. In addition, the benzene ring on 4-MBA remaining after calcination is favorable for improving electrical conductivity.…”

“…In 2009, Wang et al discovered that graphitic carbon nitride (g-C 3 N 4 ) can be used for photocatalytic water splitting to produce hydrogen (H 2 ) under visible light illumination. 20 Recently, g-C 3 N 4 has been applied in various photocatalytic areas, such as H 2 generation, [21][22][23] carbon dioxide (CO 2 ) reduction, 24,25 organic contaminant degradation, 26,27 selective organic synthesis, 28 and even bacteria disinfection, 29 owing to its chemical stability, controllable band gap, easy chemical modification, earth-abundance, facile synthesis, and nontoxicity. 30,31 However, the disadvantages of pristine g-C 3 N 4 , including low specific surface area, rapid recombination of photogenerated electron-hole pairs, and poor visible light absorption, greatly hinder its photocatalytic applications.…”

Interfacial electric field construction of hollow PdS QDs/Zn1−xCdxS solid solution with enhanced photocatalytic hydrogen evolution

“…6 Furthermore, PHE does not produce hazardous by-products or pollutants. 7,8 The hydrogen produced through this process serves as an energy carrier that, when combined with oxygen from the air, produces pollution-free water through a fuel cell device. 9,10 As a results, the development of nano-materials with modified structure of catalysts could regulate the catalytic reaction pathways for efficient hydrogen production, which has garnered significant attention.…”

In Situ Fabrication of a 2D/2D MXene/CN Heterojunction for Photothermally Assisted Photocatalytic Sterilization under Visible Light Irradiation

“…Among the light-responsive semiconductors, graphitic phase carbon nitride (CN) is an excellent candidate due to its low cost, suitable energy band structure, and visible light responsiveness. − However, its weak light utilization, low carrier separation efficiency, and small number of active sites severely influence its actual light-driven sterilization effect . Although some studies have been implemented to improve the photocatalytic activity of CN by constructing heterojunctions (Ag 2 S/CN, Ag 3 PO 4 /CN, and TiO 2 /CN), elemental doping (P-CN and S-CN), and co-catalysts (Au/CN, Ag/CN, and GO/CN) as strategies, these systems still have disadvantages such as low photocatalytic activity and high cost, which are not beneficial for their large-scale application. − …”