Phenyl carbon nitride-based self-cleaning coatings: A sustainable solution for indoor air quality management

Indoor-air pollution in public spaces and homes due to wood burning and cigarette smoking has increased the concentration of carcinogenic polycyclic aromatic hydrocarbons (PAHs) and carbonaceous soot in the air being continuously inhaled. These non-volatile compounds not only threaten the health of the humans and animals breathing that air but also deteriorates the cultural heritage artifacts and general infrastructure which would then need regular maintenance and painting. Anti-pollution paints and coatings containing TiO2 have been recently applied to manage these challenges which utilize energy-intensive UV light sources for their photocatalytic activation. Therefore, there is a need for visible-light active technologies which could mitigate the problems related to indoor air management. We report an inorganic-organic heterostructure based on the industrially utilized TiO2 and a phenyl-modified carbon nitride (PhCN), which demonstrates self-cleaning properties from wood smoke and cigarette smoke under a white LED lamp irradiation. This hybrid photocatalyst showed an efficient degradation of the organic pollutant dye Methyl Orange with a rate of 0.665 × 10􀀀 2 min􀀀 1 and Rhodamine B with a rate of 2.34 × 10􀀀 2 min􀀀 1 under visible light. The photocatalytic degradation of carbon-based matter in the smokes of wood and cigarette was monitored by reflectance measurements, colorimetric analysis and Raman Spectroscopy. The self-cleaning efficiencies of the TiO2/PhCN coatings were found to be 76.8% for wood smoke and 68.5% for cigarette smoke in 6hours under a white LED lamp. This PhCN sensitized TiO₂ material holds promise as a UV-free indoor coating/paint for smoke abatement.