A high-nuclear Co-V-O cluster was firstly isolated by lacunary polyoxoanion, resulting in the high-nuclear mixed metal-oxo cluster-containing polyoxometalate (POM), K4Na28[{Co4(O-H)3(VO4)}4(SiW9O34)4]· 66H2O (1)....A high-nuclear Co-V-O cluster was firstly isolated by lacunary polyoxoanion, resulting in the high-nuclear mixed metal-oxo cluster-containing polyoxometalate (POM), K4Na28[{Co4(O-H)3(VO4)}4(SiW9O34)4]· 66H2O (1). In 1, the{Co4(O-H)3(VO4)}4{Co16-V4}core, composed of a{Co4O4}cubane, four{Co4(OH)3}qusi-cubanes and four VO4 units, was stabilized by four lacunary A-α-{SiW9O34} units. Photocatalytic study reveals that 1 exhibits excellent photocatalytic activity for CO2-to-CO conversion with high selectivity under visible light irradiation. The turnover number (TON) and turnover frequency (TOF) reaches as high as 10492 and 0.29 s^-1, respectively. Compound 1 represents the first high nuclear TM cluster-containing POM (TM=transition-metal) with efficient visible light catalytic activity for CO2 reduction, and its photocatalytic activity is much higher than those of most reported molecular catalysts. Photoluminescence spectroscopy study reveals that photoexcitation of Ru-photosensitizer is followed by an efficient electron transfer to POMs to reduce CO2.展开更多
This study determined growth and lipid accumulation in Nannochloropsis sp. MASCC 11 cultivated at different pH, temperatures, and CO2 concentrations in 10-day period. The suitability for biodiesel production was also ...This study determined growth and lipid accumulation in Nannochloropsis sp. MASCC 11 cultivated at different pH, temperatures, and CO2 concentrations in 10-day period. The suitability for biodiesel production was also evaluated based on the fatty acid profiles of microalgae lipid. Nannochloropsis sp. MASCC 11 showed an excellent tolerance to acidic pH(as low as 4.0), high temperatures(at least 40℃), and high CO2 concentrations(5%-15%), which are major stressed conditions in flue gas. The highest algal biomass was acquired at pH of 9.0(0.44 g L^-1), a temperature of 35℃(0.63 g L^-1), and a CO2 concentration of 5%(2.27 g L^-1). Maximum lipid production was obtained at p H of 6.0(108.2 mg L^-1), a temperature of 35℃(134.6 mg L^-1), and a CO2 concentration of 5%(782.7 mg L^-1). Synthesis of polyunsaturated fatty acids(PUFAs) in biomass was stimulated under high CO_2 concentrations, remaining above 80% of total fatty acids, mainly composed of C16:3, C18:2, and C18:3. This led to the algae-based biodiesel having a lower oxidation stability, better cold flow properties, and other parameters such as its kinematic viscosity, cetane number, and specific gravity complied with ASTM or EN 14214 biodiesel specifications. Therefore, the improvement of oxidative stability needs to be considered before Nannochloropsis sp. MASCC 11 lipid can be used for biodiesel production, even if this species can grow well under stressful conditions.展开更多
基金financial support from Science and Technology Research Foundation of the Thirteenth Five Years of Jilin Educational Committee (No. JJKH20170605KJ)
文摘A high-nuclear Co-V-O cluster was firstly isolated by lacunary polyoxoanion, resulting in the high-nuclear mixed metal-oxo cluster-containing polyoxometalate (POM), K4Na28[{Co4(O-H)3(VO4)}4(SiW9O34)4]· 66H2O (1). In 1, the{Co4(O-H)3(VO4)}4{Co16-V4}core, composed of a{Co4O4}cubane, four{Co4(OH)3}qusi-cubanes and four VO4 units, was stabilized by four lacunary A-α-{SiW9O34} units. Photocatalytic study reveals that 1 exhibits excellent photocatalytic activity for CO2-to-CO conversion with high selectivity under visible light irradiation. The turnover number (TON) and turnover frequency (TOF) reaches as high as 10492 and 0.29 s^-1, respectively. Compound 1 represents the first high nuclear TM cluster-containing POM (TM=transition-metal) with efficient visible light catalytic activity for CO2 reduction, and its photocatalytic activity is much higher than those of most reported molecular catalysts. Photoluminescence spectroscopy study reveals that photoexcitation of Ru-photosensitizer is followed by an efficient electron transfer to POMs to reduce CO2.
基金supported by the National Key Technology R&D Programme (No. 2011BAD14B04)。
文摘This study determined growth and lipid accumulation in Nannochloropsis sp. MASCC 11 cultivated at different pH, temperatures, and CO2 concentrations in 10-day period. The suitability for biodiesel production was also evaluated based on the fatty acid profiles of microalgae lipid. Nannochloropsis sp. MASCC 11 showed an excellent tolerance to acidic pH(as low as 4.0), high temperatures(at least 40℃), and high CO2 concentrations(5%-15%), which are major stressed conditions in flue gas. The highest algal biomass was acquired at pH of 9.0(0.44 g L^-1), a temperature of 35℃(0.63 g L^-1), and a CO2 concentration of 5%(2.27 g L^-1). Maximum lipid production was obtained at p H of 6.0(108.2 mg L^-1), a temperature of 35℃(134.6 mg L^-1), and a CO2 concentration of 5%(782.7 mg L^-1). Synthesis of polyunsaturated fatty acids(PUFAs) in biomass was stimulated under high CO_2 concentrations, remaining above 80% of total fatty acids, mainly composed of C16:3, C18:2, and C18:3. This led to the algae-based biodiesel having a lower oxidation stability, better cold flow properties, and other parameters such as its kinematic viscosity, cetane number, and specific gravity complied with ASTM or EN 14214 biodiesel specifications. Therefore, the improvement of oxidative stability needs to be considered before Nannochloropsis sp. MASCC 11 lipid can be used for biodiesel production, even if this species can grow well under stressful conditions.
