Solar-driven CO2 reduction using modified earth-abundant ilmenite catalysts

Photocatalytic CO2 reduction is an alternative technology to the depletion of highly pollutant fossil fuels through the generation of renewable solar-based fuels. This technology requires that the photocatalysts be obtained directly from nature to scale up the process. Taking that into consideration, this work proposed the fabrication of sodium iron titanate (NaFeTiO4) photo catalysts from earth-abundant ilmenite mineral. The photocatalysts exhibited full spectrum light response, good electron transfer due to its unique tunnel structure that favored the formation of rod-like morphology. These properties promoted the solar-driven CO2 reduction to generate formic acid (HCOOH) with high selectivity (157 & mu;mol g-1 h-1). It was found that higher synthesis temperatures promoted the formation of Fe3+ species, which decreased the efficiency for CO2 reduction. Also, the possibility of reduced the CO2 molecules in the air was studied with the NaFeTiO4 samples, which resulted in an efficiency of up to 93 & mu;mol g-1 h-1 of HCOOH under visible light. The stability of the solar-driven CO2 reduction with the NaFeTiO4 photocatalysts was confirmed after seven days of continuous evaluation.

Automated summary

Photocatalytic CO2 reduction is a promising technology for generating renewable solar-based fuels. This study successfully fabricated sodium iron titanate (NaFeTiO4) photocatalysts from ilmenite mineral, which exhibited full spectrum light response and good electron transfer properties. The photocatalysts effectively reduced CO2 into formic acid with high selectivity. The synthesis temperature was found to affect the efficiency of CO2 reduction, and the NaFeTiO4 samples showed potential for reducing CO2 from air under visible light. The stability of the CO2 reduction process was also confirmed after seven days of continuous evaluation.