Photosynthesis of CH4 at a TiO2 surface from gaseous H2O and CO2

Saladin, Franz; Forss, Lars; Kamber, I.

doi:10.1039/c39950000533

Cited by 61 publications

(34 citation statements)

References 4 publications

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“…The appearance of the heavier alcohols at or above 150°C is consistent with an FTS-like mechanism becoming active as the thermal energy approaches the activation energy needed for chain formation (37,38,40). In a related study of the effect of temperature on the photochemical reduction of CO 2 to methane over TiO 2 , Saladin et al showed that the rate of methane formation increases upon going from 20 to 200°C, indicating the rate-determining step is a thermal process (41,42). Significantly, no higher C n products were reported, which we suspect is because they lacked a proper FTS cocatalyst, such as cobalt.…”

Section: Resultsmentioning

confidence: 78%

RETRACTED: Solar photothermochemical alkane reverse combustion

Chanmanee

Islam

Dennis

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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A one-step, gas-phase photothermocatalytic process for the synthesis of hydrocarbons, including liquid alkanes, aromatics, and oxygenates, with carbon numbers (Cn) up to C13, from CO2 and water is demonstrated in a flow photoreactor operating at elevated temperatures (180–200 °C) and pressures (1–6 bar) using a 5% cobalt on TiO2 catalyst and under UV irradiation. A parametric study of temperature, pressure, and partial pressure ratio revealed that temperatures in excess of 160 °C are needed to obtain the higher Cn products in quantity and that the product distribution shifts toward higher Cn products with increasing pressure. In the best run so far, over 13% by mass of the products were C5+ hydrocarbons and some of these, i.e., octane, are drop-in replacements for existing liquid hydrocarbons fuels. Dioxygen was detected in yields ranging between 64% and 150%. In principle, this tandem photochemical–thermochemical process, fitted with a photocatalyst better matched to the solar spectrum, could provide a cheap and direct method to produce liquid hydrocarbons from CO2 and water via a solar process which uses concentrated sunlight for both photochemical excitation to generate high-energy intermediates and heat to drive important thermochemical carbon-chain-forming reactions.

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Section: Resultsmentioning

confidence: 78%

RETRACTED: Solar photothermochemical alkane reverse combustion

Chanmanee

Islam

Dennis

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…[17][18][19][20][21][22] The co-adsorption of CO 2 and H 2 O on rutile (110) have been studied by both experiments and theory. 19,[23][24][25][26][27][28][29][30][31] In the experiment, the co-adsorption behavior of CO 2 and H 2 O under UHV conditions were examined by Henderson.…”

mentioning

confidence: 99%

CO₂ Capture and Conversion on Rutile TiO₂(110) in the Water Environment: Insight by First-Principles Calculations

Wang

Krack

Wen

et al. 2015

J. Phys. Chem. Lett.

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The conversion of CO2 by the virtue of sunlight has the great potential to produce useful fuels or valuable chemicals while decreasing CO2 emission from the traditional fossil fuels. Here, we use the first-principles calculations combined with the periodic continuum solvation model (PCSM) to explore the adsorption and reactivity of CO2 on rutile TiO2(110) in the water environment. The results exhibit that both adsorption structures and reactivity of CO2 are greatly affected by water coadsorption on rutile TiO2(110). In particular, the solvation effect can change the most stable adsorption configuration of CO2 and H2O on rutile TiO2(110). In addition, the detailed conversion mechanism of CO2 reduction is further explored in the water environment. The results reveal that the solvation effect cannot only greatly decrease the energy barrier of CO2 reduction but also affect the selectivity of the reaction processes. These results presented here show the importance of the aqueous solution, which should be helpful to understand the detailed reaction processes of photocatalysts.

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“…The photocatalytic reduction of CO 2 on TiO 2 has been studied in aqueous solutions [4,[6][7][8][9][10][11][12][13], in liquid CO 2 [14] and in solid-gas systems [15][16][17][18]. The efficiency of the conversion of CO 2 to fuels in aqueous suspension systems was very low when H 2 O was used as the reductant but higher yields of products were obtained in the presence of molecules acting as hole sacrificial scavengers.…”

Section: Introductionmentioning

confidence: 99%

“…The formation rate of methane was much enhanced in the presence of 2-propanol [8,14] but the presence of organic molecules can interfere with the detection of the CO 2 reduction products so that the reaction of CO 2 with H 2 O vapour is a more desirable system. Saladin et al [16] obtained CO, H 2 and CH 4 by UV irradiation of microcrystalline TiO 2 powder in the presence of CO 2 and H 2 O in gas phase. Anpo et al [15] found CH 4 as the major product produced on anatase TiO 2 powders.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic CO2 Reduction in Gas-Solid Regime in the Presence of Bare, SiO2 Supported or Cu-Loaded TiO2 Samples

Bellardita¹,

Paola²,

García‐López³

et al. 2013

COC

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Both commercial and home prepared (HP) TiO2 samples have been tested for the photocatalytic reduction of CO2. (HP) TiO2 powders were prepared by using TiCl4 or Ti(OC4H9)4 as the precursors to obtain HP1 and HP2 samples, respectively. Also HP Cu-loaded and SiO2 supported TiO2 powders were prepared. The HP samples were more active than the commercial ones for the photoreduction of CO2 with and without water vapour. HP1 produced mainly formaldehyde, HP2 principally methane. Acetaldehyde was found to be the primary product obtained when HP1 was supported on SiO2. The addition of Cu increased the photocatalytic reactivity either of bulk and SiO2-supported HP1. In particular, 1 wt % of Cu improved the formaldehyde yield obtained with the bare HP1 by one order of magnitude. Differently, the presence of Cu or SiO2 in the HP2 samples markedly reduced the production of methane.

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Photosynthesis of CH4 at a TiO2 surface from gaseous H2O and CO2

Abstract: UV irradiation of the gadsolid interface of microcrystalline Ti02 in the presence of water and carbon dioxide in the gas phase at 343 K leads to photoreduction of carbon dioxide to form carbon monoxide, hydrogen and methane.

Cited by 61 publications

References 4 publications

RETRACTED: Solar photothermochemical alkane reverse combustion

RETRACTED: Solar photothermochemical alkane reverse combustion

CO₂ Capture and Conversion on Rutile TiO₂(110) in the Water Environment: Insight by First-Principles Calculations

Photocatalytic CO2 Reduction in Gas-Solid Regime in the Presence of Bare, SiO2 Supported or Cu-Loaded TiO2 Samples

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Photosynthesis of CH4 at a TiO2 surface from gaseous H2O and CO2

Abstract: UV irradiation of the gadsolid interface of microcrystalline Ti02 in the presence of water and carbon dioxide in the gas phase at 343 K leads to photoreduction of carbon dioxide to form carbon monoxide, hydrogen and methane.

Cited by 61 publications

References 4 publications

RETRACTED: Solar photothermochemical alkane reverse combustion

RETRACTED: Solar photothermochemical alkane reverse combustion

CO2 Capture and Conversion on Rutile TiO2(110) in the Water Environment: Insight by First-Principles Calculations

Photocatalytic CO2 Reduction in Gas-Solid Regime in the Presence of Bare, SiO2 Supported or Cu-Loaded TiO2 Samples

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Product

Resources

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CO₂ Capture and Conversion on Rutile TiO₂(110) in the Water Environment: Insight by First-Principles Calculations