CO2 capture and photocatalytic reduction to hydrocarbons is an interesting yet challenging area that requires photocatalysts with the capability to capture and photoconvert CO2 simultaneously. Furthermore, earth-abundant photocatalysts with high efficiency and product selectivity are essential for commercialization. Thus, two earth-abundant photocatalysts based on copper and nickel oxides were selected to produce solar fuels from CO2 photoreduction. The photocatalysts were immobilized on commercial glass fibers substrates by a facile one-step microwave-hydrothermal method. CuxO (x = 1, 2) and NixOy (x = 1, 2 and y = 1, 3) coatings on glass fiber were evaluated as photocatalysts in two different reactors to investigate the selectivity in a continuous reactor and a batch system. Two different light sources were employed: a heterochromatic lamp to simulate part of the solar light in the continuous reactor and a LED visible light in the batch reactor. CuO/Cu2O photocatalysts exhibited a selective production of CH4 (95 µmol g−1 h−1) and CH3OH (177 µmol g−1 h−1) from CO2 photoreduction in the continuous and batch continuous systems, respectively. The superior performance was attributed to the unique rod-shape morphology, the presence of oxygen vacancies, and efficient charge transfer in the CuO/Cu2O heterostructure with high affinity towards CO2, resulting the formation of mono- and bidentate carbonate species during the CO2 photoreduction reaction. NixOy coating with 2D cubic shape produced CO (103 µmol g−1 h−1) and HCOOH (4245 µmol g−1 h−1), associating with the low CO2 affinity and less efficient charge separation compared to CuO/Cu2O heterostructure.
- CO adsorption
- CO reduction
- Solar fuels
ASJC Scopus subject areas
- Chemical Engineering (miscellaneous)
- Waste Management and Disposal
- Process Chemistry and Technology