Mesoporous ZnFe₂ O₄ Photoanodes with Template-Tailored Mesopores and Temperature-Dependent Photocurrents

Mesoporous ZnFe₂ O₄ photoanodes have been prepared via dip-coating utilizing the evaporation-induced self-assembly of two different block-copolymer templates to investigate the influence of pore geometry on the photoelectrochemcial performance of those earth-abundant photoelectrodes. The use of commercial block copolymers, triblock copolymer Pluronic^® F127 and the diblock copolymer PIB3000 as templates, leads to different pore morphologies under identical preparation conditions due to different polymer stabilities. Interestingly, pore morphology in mesoporous ZnFe₂ O₄ turned out to be less important for the photoelectrochemical performance. Contrary, sufficiently developed crystalline domains gained through optimized temperature treatment resulted in maximum photoelectrochemical performance among the investigated samples. This disproves the necessity of expensive, tailor-made polymer soft templates to synthesize high-performing mesoporous ZnFe₂ O₄ photoanodes.