In Situ Gold‐Loaded Fluorinated Titania Inverse Opal Photocatalysts for Enhanced Solar‐Light‐Driven Hydrogen Production

Abstract

AbstractThis work reports the preparation of in situ gold‐loaded fluorinated titania inverse opal (Au/F TiO2 IO) photocatalysts for enhancing solar‐light‐driven hydrogen evolution. The use of trifluoroacetic acid facilitates the surface fluorination as well as the in situ deposition of gold nanoparticles (AuNPs) at the defect sites on the TiO2 surface. The thermal treatment partially fuses the gold and titania nanoparticles leading to enhanced hot electron injection when illuminated under solar light. Au/F TiO2 IO‐215 prepared using polystyrene (PS) spheres of 215 nm size are demonstrated to be able to enhance the hydrogen evolution five‐fold relative to nanocrystalline titania photocatalyst (Au/F nc‐TiO2) due to the electronic band gap (EBG) absorption of TiO2 within the photonic band gap (PBG). Au/F TiO2 IO‐460; with the blue edge of the PBG closer to the localized surface plasmon resonance (LSPR) region of AuNPs displayed four‐fold enhancement in the hydrogen evolution with respect to Au/F nc‐TiO2. The solar light driven hydrogen evolution rates obtained for Au/F TiO2 IO‐215 and Au/F TiO2 IO‐460 photocatalysts (58.86 and 49.43 mmol h−1 g−1 respectively) are remarkably higher than the rates of inverse‐opal‐assisted hydrogen evolution experiments reported in literature. This work demonstrated a strategy for synergistically enhancing the solar light harvesting by the restructuring of Au/F TiO2 photocatalysts into inverse opals. The extended hydrogen yield by Au/F TiO2 IOs is on the order of millimoles, making them potential photocatalysts for solar hydrogen production.