![]() ![]() Several methods have been studied for improving the photocatalytic activity of organic PSs 28. ![]() Because achieving high activity for both the PS and the catalyst would be beneficial for developing versatile photocatalytic systems and applications in other relevant studies such as photoelectrochemical and supramolecular photocatalytic systems, this difficulty has led to assembling complicated molecular architectures with precious metals 44, 45, 46, 47, 48, 49. Eosin Y, which was originally reported in photocatalytic H 2 production by the Eisenberg group 38, 39, 40, is also an active PS for CO 2 reduction to formate when using Ni pyridylthiolate catalysts, although it performs with considerably lower activity (TON PS = 28) than that of the catalyst (TON Ni = 14,000) 41. gives a TON PS up to 1196 in CO generation using mono– and bis–terpydrine Fe catalysts 35, 36, 37. 2,4,5,6-tetrakis(carbazole-9-yl)-1,3-dicyanobenzene studied by Chao et al. found that a phenoxazine-based organic PS promotes the reduction of CO 2 to CO and CH 4 with a total TON PS of ~2 in 102 h 34. Purpurin, reported by Lau, Robert, and Chen groups, has shown activity for the reduction of CO 2 to CO with a series of Co, Fe, Ni polypyridyl, and Fe porphyrin catalysts 31, 32, 33, achieving an optimal TON PS of 1300 31. Acriflavine was found to exhibit a TON PS of 5, when employed with a Co dipyridyl catalyst 30. PS) in a noble-metal-free system using Fe–tetraphenylporphyrin as the catalyst (TOF Fe ~1.5 h −1) 29. For example, 9-cyanoanthracene has been reported to give a turnover frequency (TOF) of ~0.015 h −1 (vs. However, there are only a few reported organic PSs functioning in the visible region, and these systems usually have to perform with high PS concentrations due to their relatively low activity 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43. Recently, PSs based on first-row transition metals such as Cu 21, 22, 23, 24 and Zn 25 have been studied for light -driven CO 2 reduction, with turnover numbers (TONs) of 40–1566.ĭue to being readily available in nature and because they are synthetically easy to functionalize, organic PSs are promising alternative light-absorbers for photocatalytic CO 2 reduction 26, 27, 28. To provide a potentially widespread implementation, accelerating progress has been made in the development of inexpensive PSs to perform the same catalytic reaction 20. Their long-lived excited states facilitate electron transfer from the excited state of the PS (PS*) to the catalyst in an oxidative quenching pathway. Noble-metal-based PSs have demonstrated high activity in photocatalytic CO 2 reduction 6, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19. In this context, we report here a class of highly active organic PSs in precious metal-free systems for photocatalytic CO 2 reduction. ![]() For the rational design of catalytic systems, molecular approaches have shown great advantages in unraveling factors that govern photocatalytic reactions. A frequent challenge is the development of highly active PSs that promote light-driven redox reactions. However, the activity of current systems is still low for practical use. In the past decades, both homogeneous and heterogeneous AP systems have been investigated extensively for photocatalytic CO 2 reduction 7, 8. In an artificial photosynthetic (AP) scheme, a photosensitizer (PS) harvests the sunlight and transfers the energetic electron to a catalytic center which reduces CO 2 4, 5, 6. 0.Light-driven reduction of CO 2 into value-added chemicals represents a sustainable way for the direct utilization of solar energy and conversion of greenhouse gas 1, 2, 3. What is the mass, in grams, of H2 that must have reacted, to the correct number of significant figures? B. In a particular reaction, 0.575 g of NH3 forms. The balanced equation for this process is shown below. 1.16 The Haber process can be used to produce ammonia (NH3) from hydrogen gas (H2) and nitrogen gas (N2). How many moles of LiOH are needed to react completely with 25.5 g of CO2? C. 56.28 The chemical equation below shows the reaction between carbon dioxide (CO2) and lithium hydroxide (LiOH). What mass of H2O, in grams, must react to produce 50.00 g of O2? D. 2.8 Passing an electric current through a sample of water (H2O) can cause the water to decompose into hydrogen gas (H2) and oxygen gas (O2) according to the following equation. A 100.0-g sample of air contains how many moles of nitrogen? A. Air is about 78% nitrogen gas (N2) by mass.
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