Gamma irradiation produces graphitic carbon nitride with decreased water affinity

Maluangnont, Tosapol; Worathat, Supakarn; Chaithaweep, Kanokwan; Sangtawesin, Tanagorn; Khamman, Orawan; Chanlek, Narong; Vittayakorn, Naratip

doi:10.1016/j.apsusc.2025.164585

Gamma irradiation produces graphitic carbon nitride with decreased water affinity

Author(s)

Maluangnont, Tosapol

Worathat, Supakarn

Chaithaweep, Kanokwan

Sangtawesin, Tanagorn

Khamman, Orawan

Chanlek, Narong

Vittayakorn, Naratip

Date Issued

January 15, 2026

Type

Article

DOI

10.1016/j.apsusc.2025.164585

Abstract

Absorption of water on surfaces of graphitic carbon nitride (g–C3N4) can be lessened by organic molecules functionalization or post-annealing treatment. In contrast to this knowledge, we show that γ-irradiation (10–400 kGy) of g–C3N4 results in a defective material with decreased water affinity on surface and at bulk alike without those modifications. Irradiated g–C3N4 samples show diminished water content (2.52 wt% to 1.91–0.96 wt%) and decreased crystallinity but slightly increased surface area, including slit-shape pores formation in platy particles. However, their IR spectra and optical bandgap do not change. Despite the radiation-induced increase of N/C, the diminished water content is consistently observed on surfaces by XPS, and at the depth ∼1 μm deeper by EDX. It is found that γ-irradiation generates a higher proportion of pyridinic N which disfavors water adsorption. This is correlated to a decreasing apparent activation energy of water evaporation in a γ-irradiated material compared to a pristine one (29 vs 47 kJ·mol⁻¹). Also, γ-irradiation generates dangling bonds which facilitate bonding/agglomeration between particles such that the access of water to adsorption sites is prohibited. The demonstrated application of γ-irradiation to reduce water wettability, which is chemical-free and easily controllable, encourages further studies to other hydrophilic materials.

Citation

Applied Surface Science, 715, 2026