Facile and Large-Area Preparation of Porous Ag 3 PO 4 Photoanodes for Enhanced Photoelectrochemical Water Oxidation.

Photoelectrochemical (PEC) water splitting is a promising approach for renewable energy, where the development of efficient photoelectrodes, especially photoanodes for water oxidation is still challenging. In this paper, we report the novel solution-processed microcrystalline Ag3 PO4 photoanodes with tunable porosity depending on the reaction time. These porous Ag3 PO4 films were grown on large-area (4.5 × 4.5 cm2 ) silver substrates via an air-exposed and room-temperature immersion reaction. Enhanced light absorption abilities were exhibited by the synthesized Ag3 PO4 films with optimized porosity resulted from prolonged reaction times (≥20 h), due to which appreciable water splitting performance was demonstrated when they were utilized as photoanodes. Particularly, the highly porous 20 h Ag3 PO4 photoanode presented a photocurrent density of around 4.32 mA/cm2 , which is nearly three times higher than that of the nonporous 1 h Ag3 PO4 photoanode (1.48 mA/cm2 ) at 1 V vs Ag/AgCl. Moreover, superior stability of the 20 h Ag3 PO4 photoanode has also been confirmed by the 5 h successive PEC water splitting experiment. Therefore, both the scalable and facile fabrication method, and considerable photoactivity and stability of these Ag3 PO4 photoanodes together suggest their great potential for efficient solar-to-fuel energy conversion and other PEC applications.