Enhanced Photoreduction CO₂ Activity over Direct Z-Scheme α-Fe₂O₃/Cu₂O Heterostructures under Visible Light Irradiation

Abstract

Hematite-cuprous oxide (α-Fe2O3/Cu2O) nanocomposites are synthesized based on the design of Z-scheme photocatalyst for CO2 reduction. The band structure for the typical Fe2O3/Cu2O (with 1:1 mole ratio) is characterized by UV-vis reflectance spectroscopy and X-ray/ultraviolet photoelectron spectroscopy, and its heterojunction is determined to be Type II band alignment. The photoreduction CO2 activities of the heterostructures are investigated in the presence of water vapor. The CO yields are changed with Fe/Cu mole ratio, and the maximal CO yield attains 5.0 μmol·g cat(-1) after 3 h of visible-light irradiation. Besides the effect of light wavelength, H2O/CO2 molar ratio and temperature on the products is studied. The selectivity of the prepared catalysts is tunable by modulating the light wavelength. The reaction mechanism is proposed and further confirmed experimentally. The results gained herein may provide some insights into the design of Z-scheme photocatalysts for CO2 reduction.

Facile Synthesis of Novel Redox-Mediator-free Direct Z-Scheme CaIn2S4 Marigold-Flower-like/TiO2 Photocatalysts with Superior Photocatalytic Efficiency

“…In the Z-scheme mechanism, the scavenging studies has been reported for various direct Z-scheme photocatalysts such as g-C 3 N 4 /TiO 2 , NaNbO 3 /WO 3 , WO 3 /g-C 3 N 4 , BiOCl/g-C 3 N 4 , Bi 2 O 3 /g-C 3 N 4 , Bi 2 O 3 /NaNbO 3 , BiVO 4 /g-C 3 N 4 , Ag 3 PO 4 /g-C 3 N 4 , SnO 2-x /g-C 3 N 4 and α-Fe 2 O 3 /Cu 2 O. [55][56][57][58][59][60][61][62][63][64] The PL analysis results further support the superior photocatalytic efficiency of the direct Z-scheme CIS/TNP photocatalysts (Figure 9). At 330 nm excitation (Figure 9), the PL intensities of the x%-CIS/TNP composites are lower than that of TNP indicating slower recombination rates.…”

Photocatalytic Reduction of CO2 over Heterostructure Semiconductors into Value‐Added Chemicals

“…One more example is the aFe 2 O 3 /Cu 2 O Z-scheme photocatalyst. [95] It was found that the CO yield changed with Fe/Cu molar ratio. Moreover, the selectivity of the as-prepared catalysts could be tuned by modulating the wavelength of the light source.…”

Photocatalytic reduction of CO 2 with H 2 O over graphene oxide-supported oxygen-rich TiO 2 hybrid photocatalyst under visible light irradiation: Process and kinetic studies

“…These processes can be affected substantially under different experimental conditions such as the intensity and wavelength of the incident light, reactor configuration, residence time as well as the partial pressures of the reactants, i.e. CO 2 and water vapour [53][54][55][56][57][58][59][60]. Therefore, in the present work, parameters including incident light intensity as well as the partial pressures of CO 2 and water vapour were systematically varied and studied in order to determine their effects on the CO 2 photoreduction process.…”