Diesel Pollution Blues? Blue Tio2 with Tunable Oxygen-Vacancy Defects for Enhanced Photocatalytic Diesel Oil Degradation

•Blue TiO2 showed an impressive enhancement of diesel degradation compared to pristine TiO2.•Oxygen vacancy mid gap states increased optical absorption and photocatalyst charge density.•Mid gap states augment the separation of electron hole pairs by acting as trap states.•Restructuring of alkane distribution in diesel occurred after degradation.•Short chain alkanes, alkenes, alcohols and cycloalkanes were the products of degradation.