Flexible fiber optoelectrodes integrating Perovskite-Nafion-ITO layers for efficient photoelectrocatalytic water purification

Photoelectrocatalytic processes (PECs) combine photocatalysis and electrochemical principles to enhance charge carrier generation and stability within nanomaterials (NMs). Nano-enabled PECs can be used for water purification or hydrogen production. While most PEC studies focus on nanomaterial discovery to improve charge carriers generation and separation, PEC reactor design is important to maximize energy efficiency of light delivery to activate photocatalysts. Current designs face challenges due to low energy efficiencies because most reactor designs orientate light sources perpendicular to flat photocatalyst-coated electrode surfaces, and light must pass through glass materials plus water. We developed a low-cost, physically flexible catalytic polymeric optical fiber (POF) architecture, called optoelectrode fibers, embedded with electrically-conductive indium tin oxide (ITO) nanomaterials (NMs) plus TAB₃Bi₂Br₇I₂ perovskite (ABI) visible-photocatalysts in Nafion-PVDF polymers surface layer. The PEC-POF architecture achieves > 6000% larger surface area than flat glass electrodes, > 90% organic pollutant removal in water, and > 300% better incident photon-to-current than the same ABI-NM deposited on a conventional ITO-coated flat glass-plate under low energy irradiation. POFs are useful because are agonistic to the type of NM, facilitating deposition of NMs tunable to specific wavelengths using LED or polychromatic light sources. Bundling large numbers of POF optoelectrodes together achieves reactors with orders of magnitude higher packing geometries (m² of catalyst surface per m³ of reactor volume) than flat-electrode PEC reactors, enabling the optoelectrode fiber to address environmental problems.