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

Abstract

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 μmol h–1 L–1.

Preparation of FeS2/TiO2 nanocomposite films and study on the performance of photoelectrochemistry cathodic protection

“…Hematite type has no photoelectric property, while it will change to pyrite type when the temperature exceeds 350 °C; pyrite FeS 2 is a kind of non-toxic, stable physical and chemical properties, low cost, easy to obtain semiconductor materials, and it has appropriate band gap width (0.95 eV indirect band gap, 1.03 eV direct band gap width), and high light absorption coefficient (6 × 10 –5 cm −1 ) 20 , which make FeS 2 is useful for the preparation of optical devices that can utilize visible light. Han 21 et al prepared wormlike FeS 2 /TiO 2 nanotube composites, which were used for photocatalytic reduction of CO 2 to methanol under visible light, and the doping and recombination of FeS 2 nanoparticles on TiO 2 nanotubes not only broadened the light absorption range of TiO 2 , but also improved the photocatalytic reduction ability, which increased the methanol yield to 91.7 μmol/h/L. Rashid 22 and others prepared stable anatase TiO 2 composite pyrite FeS 2 composite nanocrystals to improve the photocatalytic decomposition of methyl blue, and the catalytic decomposition of organic compounds increased from 15 to 75 mg/L within 180 min.…”

Activity Enhancement of Defective Carbon Nitride for Photocatalytic Ammonia Generation by Modification with Pyrite

“…48,49 Thus, composites with FeS2 have been employed for dye degradation, H2 evolution, CO2 reduction and NRR. 50,51,52,53,54,55 Apart from improving the light absorption properties in composites, FeS2 can act as an efficient electrocatalyst, which has been shown separately for the H2 evolution, as well as for the NRR. 56,57,58,59,60 There have been some fairly recent reports on the formation of heterojunctions of FeS2 with C3N4 and their application in organic dye and antibiotics removal.…”

<p>High UV-Vis-NIR Light-Induced Antibacterial Activity by Heterostructured TiO₂-FeS₂ Nanocomposites</p>

“… 34 FeS 2 -TiO 2 NCs also exhibited high photoelectric cell (PEC) performance for reducing CO 2 to methanol because the bandgap energy of FeS 2 -TiO 2 NCs is narrowed to 1.70 eV for significant enhancement of the photocatalytic performance with visible (Vis) light irradiation. 35 Furthermore, TiO 2 -FeS 2 NCs with photocatalytic applications in the UV-Vis-NIR region have shown great potential to be TiO 2 -based photocatalysts in practical applications for highly active photocatalytic hydrogen evolution. 36 However, antibacterial applications with the use of photoactive, biocompatible, and low-cost TiO 2 -FeS 2 NCs are still limited.…”