A hybrid fuel cell for water purification and simultaneously electricity generation

● A novel hybrid fuel cell （F-HFC） was fabricated.● Pollutant degradation and synchronous electricity generation occurred in F-HFC.● BiOCl-NH4PTA photocatalyst greatly improved electron transfer and charge separation. ● Pollutant could act as substrate directly in ambient conditions without pretreatment.● The mechanism of the F-HFC was proposed and elucidated.The development of highly efficient energy conversion technologies to extract energy from wastewater is urgently needed, especially in facing of increasing energy and environment burdens. Here, we successfully fabricated a novel hybrid fuel cell with BiOCl-NH4PTA as photocatalyst. The polyoxometalate （NH4PTA） act as the acceptor of photoelectrons and could retard the recombination of photogenerated electrons and holes, which lead to superior photocatalytic degradation. By utilizing BiOCl-NH4PTA as photocatalysts and Pt/C air-cathode, we successfully constructed an electron and mass transfer enhanced photocatalytic hybrid fuel cell with flow-through field （F-HFC）. In this novel fuel cell, dyes and biomass could be directly degraded and stable power output could be obtained. About 87 % of dyes could be degraded in 30 min irradiation and nearly 100 % removed within 90 min. The current density could reach up to 267.1 μA/cm2; with maximum power density （Pmax） of 16.2 μW/cm2 with Rhodamine B as organic pollutant in F-HFC. The power densities were 9.0 μW/cm2, 12.2 μW/cm2, and 13.9 μW/cm2 when using methyl orange （MO）, glucose and starch as substrates, respectively. This hybrid fuel cell with BiOCl-NH4PTA composite fulfills the purpose of decontamination of aqueous organic pollutants and synchronous electricity generation. Moreover, the novel design cell with separated photodegradation unit and the electricity generation unit could bring potential practical application in water purification and energy recovery from wastewater.