Using TiO2 in photocatalytic reactors: VOCs, NOx, CO2 removal and H2 production

Currently, TiO 2 is the most versatile and promising photocatalyst and has settled to the forefront of research and development in environmental remediation. Hence, in this work, we extensively review from the morphologies of TiO 2 based photocatalysts used in the treatment of different groups of gaseous pollutants, the strategies employed to improve their efficiency, the photo reactor designs and most importantly the Technology Readiness Level (TRL) of the photoreactors. Despite the many ways employed to improve the efficiency of TiO 2 , more work is needed to strike a balance between these modification strategies, the counter effect they could have on TiO 2 photocatalytic activity, the sustainability of the synthesis methods and the environmental impact. Some information is also included in this work on the use of TiO 2 based materials in the production of hydrogen as it significantly contributes to the decrease of gaseous air pollutants resulting from the use of conventional fossil fuels. Finally, we identified some challenges that could be encountered with the photo reactor designs and provided an outlook to the future work that could address these gaps.