In the context of growing energy shortages and environmental issues, photocatalytic technologies are becoming particularly relevant. Using sunlight as the only energy source, photocatalysis enables the production of synthetic fuels, such as hydrogen and methane.
A key factor affecting photocatalytic efficiency is the choice of semiconductor material, which must combine chemical stability, visible-light activity, and favorable textural and surface properties. Graphitic carbon nitride (g-C₃N₄) with a partially oxidized surface is a promising candidate. Oxidation of g-C₃N₄ via hydrothermal treatment in H₂O₂ solution significantly increases its specific surface area, enhances photoinduced conductivity, and introduces O-containing functional groups. These modifications improve hydrophilicity, facilitate reactant adsorption, and ensure strong anchoring of cocatalyst species in the form of nanoparticles or single atoms.
The photocatalytic performance of oxidized g-C₃N₄ loaded with 0.1–1 wt.% Pt was investigated in two reactions: hydrogen evolution (HER) from aqueous organic substrates under LED irradiation (λmax = 440 nm) and simulated sunlight (AM 1.5 G), and CO₂ reduction under LED irradiation (λmax = 405 nm). In the CO₂ reduction reaction, the use of 1 wt.% Pt/g-C₃N₄ produced CH4 as the primary product at a rate of 2.9 μmol·gcat⁻¹·h⁻¹, with an overall electron consumption rate of 26.3 μmol·gcat⁻¹·h⁻¹. The photocatalysts containing 0.5 and 1 wt.% Pt exhibited similar hydrogen evolution rates from glucose solutions of up to 310 μmol·gcat⁻¹ h⁻¹, indicating the efficient utilization and uniform dispersion of Pt species [1].
TEM, XPS, ATR-FTIR and EXAFS analyses confirmed the structural and chemical stability of the photocatalysts before and after HER, demonstrating that the surface composition and Pt distribution remained unchanged.
[1] Kharina, S.; Kurenkova, A.; Aydakov, E.; Mishchenko, D.; Gerasimov, E.; Saraev, A.; Zhurenok, A.; Lomakina, V.; Kozlova, E. Activation of g-C3N4 by Oxidative Treatment for Enhanced Photocatalytic H2 Evolution. Appl. Surf. Sci. 2025, 698, 163074, doi:10.1016/j.apsusc.2025.163074.
