Widely Controllable Syngas Production by a Dye‐Sensitized TiO₂ Hybrid System with Re^I and Co^III Catalysts under Visible‐Light Irradiation

Abstract

Visible-light irradiation of a ternary hybrid catalyst prepared by grafting a dye, an H evolving Co catalyst and a CO-producing Re catalyst on TiO have been found to produce both H and CO (syngas) in CO -saturated N,N-dimethyl formamide (DMF)/water solution containing a 0.1 m sacrificial electron donor. The H /CO ratios are effectively controlled by changing either the water content of the solvent or the molar ratio of the Re and Co catalysts ranging from 1:2 to 15:1. The controlled syngas formation is discussed in terms of competitive electron flow from TiO to each of the CO -reduction and hydrogen-evolving sites depending on the efficiencies of the two catalytic reaction cycles under given reaction conditions.

Highly Efficient Photoreduction of Low‐Concentration CO2to Syngas by Using a Polyoxometalates/RuIIComposite

“…The generation of H 2 is more efficient than that of CO, probably owing to the large amount of water as the H + source whereas the dramatic abatement of CO may be rooted in the lower solubility of CO 2 molecules in water (ca. 0.034 m ) than in MeCN (ca. 0.279 m ) …”

Organometallic Iridium(III) Complex Sensitized Ternary Hybrid Photocatalyst for CO2 to CO Conversion

“…This is consistent with the dye concentration dependency observedi no ur previous Re I -based ternary analogues (dye/TiO 2 /Re I catalyst). [34,35,[37][38][39][40] Figure 7s hows typical plots of TON and mmol versusi rradia-tion time for the CO formation of the IrP(0.1 mmol)/TiO 2 /ReP ternary series. Under the optimum condition, the AQYs of IrP/ TiO 2 /ReP hybrids at l = 436 nm were determined to be 0.16-0.40 %( Ta ble3).…”

“…The additives commonly contributet o the proton-coupled electron-transfer processes for two-electron reduction of CO 2 to CO, as well as to the hydrolysis of key CO 2 intermediates, LReCOOH( L= bpy derivatives), consequently increasing the overall CO 2 to CO conversion activity.Differences in water content in DMF media effectively modulate the CB energy level of TiO 2 . [35,37,38] As reported for our previoust ernary hybrid system, [35,38] the maximum effect of water was obtained with 3vol %water,which led to the optimum alignment of flat-band potential( V fb )f or smooth electron transport from excited-triplet IrP to ReP through TiO 2 .O nt he other hand, triethanolamine (TEOA) has been applied to thep resent ternary system because of its positive role as ab ase to inhibit back electron transfer from the OER species (IrPC À in this study) to BIHC + ,asi nE quation (1), [18,56] as well as an effectiveC O 2 capturer by complexation of ReÀCOOÀTEOA, [57] whicha llows the use of CO 2 at dilute CO 2 sources. In this additive experiment, unlike both TFE and water additives (3 vol %), the contento fT EOA was adjusted to 20 vol %f or exact comparison with previous results in am ixture of DMF/TEOA (5:1, v/v).…”

“…[14] The dye-sensitized photocatalysis (DSP) approachi nvolves an n-type TiO 2 semiconductor as an electron mediator anda sa scaffold that ideally links the molecular or metal components by coadsorption onto the TiO 2 surface. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] The DSP system rapidly consumes the reactive excited (IrPS*) or reduced (IrPSC À )s pecies with the alleviation of intermoleculari nteraction by low average coverage of the PS, consequently lessening the photodegradation of IrPS. Such coassembly of components onto as emiconductor surfacec an also allow no limitation of solvent selection based on heterogenization, with easy preparation and tunability of the DSP system.…”

The Role of Natural Gas and Renewable Energy in Curbing Carbon Emission: Case Study of the United States

“…However, the United States is currently experiencing negative growth in CO 2 emissions, while the country's GDP per capita has continued to grow since 2007. Based on the BP Statistical Review of World Energy 2016 [10,[18][19][20], US carbon emissions increased year-on-year before 2007. Then, between 2007 and 2015, US carbon emissions provides a good example for other countries around the world on how to decrease carbon emissions without holding back economic progress.…”