Impact of soot deposits on waste gas-to-electricity conversion in a TiO2/WO3-based photofuel cell

[Display omitted] •TiO2/WO3 heterostructures are studied for soot oxidation and photocurrent generation.•Efficient soot degradation is achieved mainly through a thin TiO2 top layer.•A dense WO3 bottom layer ensures high photocurrent generation.•Real-life outdoor autonomous proof of concept is presented in sunny and shaded areas.•Soot degradation rate is ten times higher than the actual rate of outdoor soot deposition. An unbiased photo-fuel cell (PFC) is a device that integrates the functions of a photoanode and a cathode to achieve simultaneous light-driven oxidation and dark reduction reactions. As such, it generates electricity while degrading pollutants like volatile organic compounds (VOCs). The photoanode is excited by light to generate electron-hole pairs, which give rise to a photocurrent, and are utilized to oxidise organic pollutants simultaneously. Here we have systematically studied various TiO2/WO3 photoanodes towards their photocatalytic soot degradation performance, PFC performance in the presence of VOCs, and the combination of both. The latter thus mimics an urban environment where VOCs and soot are present simultaneously. The formation of a type-II heterojunction after the addition of a thin TiO2 top layer over a dense WO3 bottom layer, improved both soot oxidation efficiency as well as photocurrent generation, thus paving the way towards low-cost PFC technology for energy recovery from real polluted air.