Engineering organic/inorganic hierarchical photocathode for efficient and stable quasi-solid-state photoelectrochemical fuel cells.

Graphical abstract A quasi-solid-state tandem photoelectrochemical fuel cell that yields an open circuit voltage of 0.78 V and a maximum power density of 130 μW·cm−2 was assembled by utilizing hydrogel electrolyte, Au-TiO 2 NRAs photoanode and pTTh-Cu 2 O pohotocathode. The pTTh-layer protected Cu 2 O exhibited remarkably improved photostability as well as achieved significantly accelerated oxygen reduction reaction performance. Highlights • A quasi-solid-state tandem photoelectrochemical fuel cell was fabricated. • Polyterthiophene coated p-type cuprous oxide was prepared as photocathode. • Photocathode exhibited improved anti-photocorrosion and photocatalytic activity. • Gold nanoparticles decorated TiO 2 nanorod arrays was presented as photoanode. Abstract Photoelectrochemical fuel cells (PFCs) serve as a model system for harvesting electric energy from solar and biomass based on anodic fuel oxidation and cathodic oxygen reduction reaction (ORR). However, the sluggish ORR thereby limits the performance of PFC. Herein, we present a novel photocathode with polyterthiophene (pTTh) coated p-type cuprous oxide (Cu 2 O) (pTTh-Cu 2 O) that achieves boosted ORR kinetics, as well as exhibits remarkably improved photostability. By utilizing a hydrogel electrolyte which can avoid the leakage and volatilization of liquid electrolyte, a quasi-solid-state PFC device with eminent stability that consists of gold nanoparticles (Au NPs) decorated TiO 2 nanorod arrays (Au-TiO 2 NRAs) photoanode and pTTh-Cu 2 O photocathode can be assembled. And the fabricated PFC exhibits outstanding performance that yields an open circuit voltage of 0.78 V and a maximum power density of 130 μW·cm−2 utilizing glucose as feeding under illumination. Furthermore, the as-prepared quasi-solid-state PFC demonstrates its potential for practical application by lighting a commercial light-emitting diode (LED). It is our believe that such rational design not only can be expanded for organic wastes degradation and water splitting, but also shed a light on the development of portable electronics driven by solar. [ABSTRACT FROM AUTHOR]