Tuning the reactivity of g-C₃N₄ photocatalysts using liquid phase exfoliation

To address global water quality issues photocatalysis has emerged as a sustainable advanced oxidation process to degrade aqueous organic pollutants. Layered semi-conductors, such as graphitic carbon nitride and other two-dimensional materials, have shown promise as photocatalysts for water treatment and splitting applications. Despite this, improving the reactivity of these materials typically involves lab-based chemical processing steps that are challenging to scale and can indirectly introduce their own sustainability issues with toxic reagent use. To improve the catalytic performance and drive sustainable real-world deployment, scalable production methods are required. Here we show that rapid liquid phase exfoliation using shear-driven methods can enhance the reactivity of g-C₃N₄, achieving up to 2.5× increase in the removal of organic dye model pollutants compared to the bulk material. We show that organic-inorganic two-dimensional material heterostructures (g-C₃N₄/MoS₂) also outperform bulk catalysts, however, the simple action of shear exfoliation is found to be the primary reason for enhancement. We reveal the mechanisms behind these enhancements and verify the catalysts ability to degrade several model pollutants (Indigo Carmine, Rhodamine B, Acid Red 266), including those containing tough-to-break C-F bonds such as those present in persistent environmental pollutants.