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FeO–CeO2 nanocomposites: an efficient and highly selective catalyst system for photothermal CO2 reduction to CO.
- Source :
- NPG Asia Materials; 1/24/2020, Vol. 12 Issue 1, p1-9, 9p
- Publication Year :
- 2020
-
Abstract
- Solar-driven catalysis is a promising strategy for transforming CO<subscript>2</subscript> into fuels and valuable chemical feedstocks, with current research focusing primarily on increasing CO<subscript>2</subscript> conversion efficiency and product selectivity. Herein, a series of FeO–CeO<subscript>2</subscript> nanocomposite catalysts were successfully prepared by H<subscript>2</subscript> reduction of Fe(OH)<subscript>3</subscript>-Ce(OH)<subscript>3</subscript> precursors at temperatures (x) ranging from 200 to 600 °C (the obtained catalysts are denoted as FeCe-x). An FeCe-300 catalyst with an Fe:Ce molar ratio of 2:1 demonstrated outstanding performance for photothermal CO<subscript>2</subscript> conversion to CO in the presence of H<subscript>2</subscript> under Xe lamp irradiation (CO<subscript>2</subscript> conversion, 43.63%; CO selectivity, 99.87%; CO production rate, 19.61 mmol h<superscript>−1</superscript> g<subscript>cat</subscript><superscript>−1</superscript>; stable operation over 50 h). Characterization studies using powder X-ray diffraction and high-resolution transmission electron microscopy determined that the active catalyst comprises FeO and CeO<subscript>2</subscript> nanoparticles. The selectivity to CO of the FeCe-x catalysts decreased as the reduction temperature (x) increased in the range of 300–500 °C due to the appearance of metallic Fe<superscript>0</superscript>, which introduced an additional reaction pathway for the production of CH<subscript>4</subscript>. In situ diffuse reflectance infrared Fourier transform spectroscopy identified formate, bicarbonate and methanol as important reaction intermediates during light-driven CO<subscript>2</subscript> hydrogenation over the FeCe-x catalysts, providing key mechanistic information needed to explain the product distributions of CO<subscript>2</subscript> hydrogenation on the different catalysts. Catalysis: Reclaiming carbon dioxide A nanomaterial that helps convert carbon dioxide to more useful chemicals has been developed by researchers in China. One potential method is to convert the carbon dioxide into carbon monoxide using a reaction known as reverse water-gas shift, and then use further reactions to convert this into fuel, or produce useful chemicals such as methanol or methane. This reaction normally requires high temperatures, and a catalyst is required to make the conversion efficient at lower, more practical temperatures. Tierui Zhang from the Technical Institute of Physics and Chemistry in Beijing and co-workers developed a nanocomposite based on iron and cerium with excellent performance in converting carbon dioxide into carbon monoxide with hydrogen only under light irradiation. This result indicates the potential of solar-driven catalysis for transforming carbon dioxide into fuels. A series of FeO-CeO<subscript>2</subscript> nanocomposite catalysts (FeCe-x) were successfully fabricated by hydrogen reduction of hydroxide precursors at temperatures (x) between 200–600 °C. A FeCe-300 catalyst with a Fe:Ce ratio of 2-1 exhibited excellent performance for photothermal CO<subscript>2</subscript> hydrogenation to CO (CO selectivity = 99.87%, CO production rate 19.61 mmol h<superscript>−1</superscript> g<subscript>cat</subscript><superscript>−1</superscript>, excellent stability). The FeO phase was effective in promoting the reverse water-gas shift (RWGS, CO<subscript>2</subscript> + H<subscript>2</subscript> → CO + H<subscript>2</subscript>O). Catalysts prepared at higher reduction temperatures contained both Fe<superscript>0</superscript> and FeO, with the Fe<superscript>0</superscript> catalyzing the Sabatier reaction (CO<subscript>2</subscript> + 4H<subscript>2</subscript> → CH<subscript>4</subscript> + 2H<subscript>2</subscript>O) and thus lowering FeCe-x catalyst selectivity to CO. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 18844049
- Volume :
- 12
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- NPG Asia Materials
- Publication Type :
- Academic Journal
- Accession number :
- 161396762
- Full Text :
- https://doi.org/10.1038/s41427-019-0171-5