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Surface morphology of Cu-based catalysts is considered as an important factor affecting both activity and product selectivity of electrochemical reduction of CO2. In this work, surface cavity effect on C2H4 formation was investigated using Cu2O cubes: solid cubes, cavity cubes, and broken cubes, typically representing smooth surface, cavity surface, and rough surface. With respect of C2H4 selectivity, cavity cubes show the significantly enhanced faradaic efficiency (FE) of C2H4, which is 2.7 and 1.7 times higher than those for solid cubes and broken cubes respectively. Moreover, a ratio of CO produced by CO2 reduction reaction (CO2RR) converted to CH4 and C2H4 was calculated to assess the extent of CO further reduction for a catalyst. As noted, cavity cubes exhibited a highest ratio of 29.5%, in contrast with the lower ratio of 13.0% on broken cubes and 14.9% on solid cubes. Consequently, the role of surface cavity is reflected in two effects, the increased CO formation due to higher electrochemical surface area as compared to the smooth surface, and meanwhile the increased ratio of CO converted to hydrocarbons and alcohols due to porous feature as compared to the rough surface with a comparable high electrochemical active surface area (ECSA). What's more, when applied in a flow cell reactor with a gas diffusion electrode, cavity cubes also achieved much higher C2 selectivity of 37.7% FEC2 than solid cubes and broken cubes. Our work provides a facile strategy for improving the catalytic C2+ product selectivity of Cu2O-based catalysts for CO2RR through modifying surface morphology. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of carbon dioxide to fuels has been recognized as a perspective way to address the environmental and energy issues. Herein, the novel Au decorated Cu2O electrocatalysts were synthesized via the galvanic replacement reaction and the successive pre‐reduction by linear voltammetry (LSV) method. In contrast to Cu2O, CO formation became dominant over HCOOH and H2 on AuxCu2O, and a remarkably enhanced selectivity of C2H4 was obtained beyond −1.1 V vs. RHE. Among them, Au0.02Cu2O exhibited the highest Faraday efficiency (FE) of C2H4 of 24.4 % at −1.3 V vs. RHE, which was as high as 2∼2.5 and 5 times of those on other two AuxCu2O and bare Cu2O, respectively. Meanwhile, it is demonstrated that the optimal ratio of Au/Cu was essential for effective sequential catalysis between Au and Cu2O to enhance C−C coupling. Furthermore, the effect of copper states resulting from different pre‐reduction methods on the selectivity of C2H4 was explored. A half decrease of C2H4 FE was observed on HPR‐Au0.02Cu2O (high potential reduced) relative to the LSV reduced Au0.02Cu2O, which was ascribed to the different content of Cu0 and residual Cu+ in two catalysts. Our results demonstrate an effective approach to construct Cu2O based bimetallic catalysts for ethylene formation from CO2. [ABSTRACT FROM AUTHOR]

Forty oilseed sunflower cultivars were screened in two soil types for phytoremediation of Cd coupled with maximum biomass yield and oil production. Several cultivars exhibited a significant difference in biomass and yield with enhanced uptake in shoots and low accumulation in roots from two Cd-contaminated soil types, an Oxisol and an Iceptisol. The Transfer Factor of Cd was >1 in several cultivars in both soil types, where as a significant difference in phytoextraction of Cd was observed in the Oxisol (acidic soil), greater than in the Inceptisol (alkaline soil). The results revealed that of the 40 cultivars, S9178, Huanong 667in the Oxisol and cvs. DW 667, HN 667, Huanong 667 and 668F1 in the Inceptisol showed a high biomass, better yield and enhanced accumulation of Cd in the shoots but a lesser accumulation in oil. The screened cultivar S 9178 produced the greatest amount of oil (55.6%) with 77% oleic acid, which makes it suitable for human consumption. Cultivar Huanong 667 was found to be the highest accumulating cultivar in both soil types. It is therefore suggested that some sunflower cultivars do exhibit phytoremediation potential together with agro-production potential. Image 1 • Forty sunflower cultivars were screened for phytoremediation in Oxisol and Inceptisol. • Cultivar S-9178 was found to be a high Cd accumulator with maximum oil production and highest oleic acid content. • Cd phytoextraction methodologies can be promoted along with economic agro-production. • Propose selection strategies of oilseed sunflower for phytoremediation of Cd contaminated soils. [ABSTRACT FROM AUTHOR]