The Design of Supramolecular Assemblies with Metal Salt as Precursors Enables The Growth of Stable Polymeric Carbon Nitride Photoanodes

Abstract

Polymeric carbon nitrides (CN) have gained significant interest as photoanodes in photoelectrochemical cells (PEC). A widely researched approach for synthesizing CN films with controlled optical and photoelectrochemical properties relies on using supramolecular assemblies as the precursors for thermal polymerization over a transparent conductive substrate. However, the formation of supramolecular assemblies is highly dependent on the temperature and solubility in a given solvent, limiting the full potential of this method. Moreover, the intercalation of metal ions is challenging due to the use of polar solvents. Here, this study shows a new way of synthesizing supramolecular assemblies with metal ions using a solvothermal approach. The solvent, monomer composition, salt quantity, reaction temperature, and film thickness are varied in this study. As a result, well‐attached, uniform CN films with good optoelectronic properties are achieved. The synthesized photoactive CN films exhibit very low onset potentials and reach ≈0.13, ≈0.15, and 0.30 ± 0.01 mA cm−2 photocurrents in 0.1 m phosphate buffer (neutral) solution, 0.1 m KOH(aq) (basic) solution, and 0.1 m KOH solution containing 10 vol.% triethanolamine as the hole scavenger, respectively.

NC Meets CN: Porous Photoanodes with Polymeric Carbon Nitride/ZnSe Nanocrystal Heterojunctions for Photoelectrochemical Applications

“…Fourier-transform infrared (FTIR) spectra of both CNGO and CNGO/ZnSe films exhibited similar peaks in the 1180–1630 cm –1 range, which are assigned to the characteristic stretch modes of aromatic CN heterocycles (Figure S4), whereas the peak at 812 cm –1 corresponds to the breathing mode of the heptazine units. , The broad band between 3000 and 3600 cm –1 is consistent with the presence of −NH 2 groups. UV–vis diffuse reflectance spectroscopy (DRS) of the CNGO electrode (Figure S5) shows an absorption onset of 450 nm with a direct band gap ( E g ) of 2.82 eV, obtained from the Tauc plot as displayed in Figure a, while the modified CNGO with ZnSe NCs demonstrates an extended absorption tail beyond 500 nm with an estimated band gap of 2.68 eV.…”

Melamine Cyanaurate Microrods Decorated with SnO2 Quantum Dots for Photoelectrochemical Applications

“…The stated results indicate that the structures are fine-quality crystals and approve the demonstration of SnO 2 in the crystalline structure, which is in a virtuous pact with the XRD studies. In addition, the broadening peak at 3414 cm −1 with defined intensity was noticed, and suspected to be due to the stretching of the hydroxyl group [32]. The frequency shift may be credited to the influence of the stress and strain that occurred throughout the coordination bonding of the nanostructure of SnO 2 with melamine cyanaurate.…”