Air and Surface Purification Using Heterogeneous Photocatalysis: Enhanced Indoor Sanitisation Through W18O49 and ZnO Catalyst Systems

Indoor air quality management has become increasingly critical for public health, particularly after the global COVID-19 respiratory disease outbreaks that highlighted airborne pathogen transmission risks. This review investigates an advanced air and surface purification method that is used in devices utilising heterogeneous photocatalysis with tungsten oxide (W18O49) and zinc oxide (ZnO) catalyst systems to generate controlled concentrations of hydrogen peroxide for continuous indoor sanitisation. The photocatalytic system converts ambient water vapour into aerosolised hydrogen peroxide at concentrations of 0.04–0.05 ppm, significantly below established safety thresholds, while maintaining effective antimicrobial activity. The W18O49 catalyst demonstrates superior visible-light absorption compared to conventional titanium dioxide (TiO2) systems, with ZnO serving as an effective cocatalyst to reduce electron–hole recombination and enhance reactive oxygen species generation. Safety analysis based on OSHA, WHO, and ACGIH guidelines confirms that continuous exposure to these low hydrogen peroxide concentrations poses no health risks to occupants. Real-world applications demonstrate up to 90% reduction in airborne pathogens and a 20–30% decrease in sick leave rates in office environments. The technology offers significant economic benefits through reduced healthcare costs and improved productivity while providing environmentally sustainable air purification without harmful residues. This photocatalytic approach represents a scientifically validated, safe, and economically viable solution for next-generation indoor air quality management across healthcare, educational, commercial, and residential sectors.