Degradation of gaseous HCHO in a rotating photocatalytic fuel cell system with an absorption efficiency of up to 94

[Display omitted] •A rotating PFC system with high capacity for gaseous HCHO adsorption was proposed.•The rotating PFC system displayed an excellent gaseous HCHO degradation capacity.•The system exhibited less sensitive on ambient humidity.•Degradation of gaseous HCHO was concurrently achieved with energy recovery.•A liquid-film air purifier was designed and a good performance was obtained. Removing gaseous formaldehyde (HCHO) using photocatalyst oxidation is of great interest. Herein, a photocatalytic fuel cell (PFC) with a rotating photoanode was proposed for gaseous HCHO degradation with the features of efficient absorption, fast oxidation and humidity less sensitivity. The results indicated that the as-fabricated rotating PFC system can facilitate the absorption of gaseous HCHO (up to 94.0%) in the thin liquid film formed on the upper anode surface, and have an efficient separation of the photoinduced electron-hole pairs on the TiO2 photoanode. Within this context, the rotating PFC showed a superior HCHO degradation efficiency of 82.4%, which was 3.6 times higher than that of the conventional gaseous HCHO degradation. In addition, the rotating PFC exhibited a high stability under different relative humidity, an effective power generation and an excellent reproducibility for HCHO degradation. For the proof-of-concept presented here, a new type of liquid-film air purifier was designed and a good gaseous HCHO purification was obtained. Therefore, the rotating PFC system has a great promising application in gaseous HCHO removal and simultaneous energy recovery.