Worm-like FeS2/TiO2 Nanotubes for Photoelectrocatalytic Reduction of CO2 to Methanol under Visible Light

Photoelectrocatalytic (PEC) reduction of CO2 to hydrocarbons provides a great technique for CO2 utilization, renewable energy transformation, and storage. Iron disulfide (FeS2), as an earth-abundant and nontoxic semiconductor, has narrow band gap energy, high photovoltaic conversion efficiency, and light absorption, making it very promising as a photoelectrode in a PEC cell. Herein, novel worm-like FeS2/TiO2 nanotubes (NTs) was prepared by introducing FeS2 on TiO2 NTs and exhibited excellent PEC performance for CO2 reduction to methanol. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) showed that worm-like FeS2 was densely packed on the TiO2 NT substrate. By introduction of FeS2 on TiO2 NTs, the visible light absorption was improved greatly and the energy band gap energy was narrowed to 1.70 eV, which significantly enhanced the photocatalytic performance under visible light. Furthermore, the resistance was reduced with increasing electrocatalytic ability. The major product of PEC reduction of CO2 was methanol, reaching 91.7 mu mol h(-1) L-1.