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The hydrogenation of carbon dioxide (CO2) to produce light olefins is one of the most promising ways to utilize CO2 in power plant flue gas. However, the low concentration of CO2 (~10%) and the existence of water steam in the flue gas pose great challenges for the catalyst design. To address these problems, we introduced a Mg promoter and hydrophobic component into the Fe-based catalyst to improve the CO2 adsorption capacity and weaken the negative effects of water. The yield of light olefins on an optimized multifunctional Fe-based catalyst increased by 37% in low-concentration CO2 hydrogenation with water steam. A variety of characterizations proved that the Mg promoter played critical roles in regulating the adsorption capacity of CO2, increasing the surface electron density of Fe species, and promoting the formation of iron carbide active sites. The hydrophobic component mainly contributed to constraining the oxidation of iron carbides via water steam. It benefited from the rational design of the catalyst, showing how our multifunctional Fe-based catalyst has great potential for practical application in CO2 utilization. [ABSTRACT FROM AUTHOR]

TiO2-based nanosheets (TNS) modified with Fe2O3 and Y2O3 particles (Fe2O3/Y2O3@TNS), possessing a laminar structure with large specific surface area of 382 m2 g−1, were synthesized via a one-pot hydrothermal method. The optimized Fe2O3/Y2O3@TNS (Fe/Y/Ti = 0.1 at%: 0.75 at%: 1) exhibited high photocatalytic efficiency due to the synergistic effect, and the photodegradation rate towards RhB and K2Cr2O7 solutions were 5.82-fold and 2.35-fold higher, respectively, as compared to TNS under visible light. Simultaneous photocatalytic degradation in the Cr(VI)–phenol coexisting system revealed that there was synergism between Cr(VI) reduction and phenol degradation for promoting photocatalytic efficiency. Besides, Fe2O3/Y2O3@TNS demonstrated strong adsorption and excellent photocatalytic regeneration performance for high-chroma crystal violet (CV), showing potential application in the removal of organic or inorganic pollutants. Based on photoluminescence (PL) spectra and photocurrent (SPC) methodology, the separation efficiency of photogenerated e−–h+ pairs could be significantly strengthened. A possible mechanism for enhanced photocatalytic efficiency under visible light was proposed. [ABSTRACT FROM AUTHOR]