Effect of CO2 pressure on photocatalytic reduction of CO2 using TiO2 in aqueous solutions

Mizuno, Takayuki; Adachi, Kengi; Ohta, Kouji; Saji, Akira

doi:10.1016/1010-6030(96)04334-1

Cited by 111 publications

(76 citation statements)

References 14 publications

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“…Whereas these advances have led to improvements in catalytic efficiency and quantum yields, little progress has been realized in extending the selectivity of the reaction to favor the more desirable, higher carbon number liquid hydrocarbons (29). Although reports of trace amounts of products, such as ethane, ethanol, acetic acid, propanol, and butanol, are not unknown (30)(31)(32)(33)(34), they are the exception and frequently the underlying cause for their generation is unknown. Of these reports, the work of Roy et al (35) and Varghese et al (36) stands out.…”

mentioning

confidence: 99%

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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mentioning

confidence: 99%

RETRACTED: Solar photothermochemical alkane reverse combustion

Chanmanee

Islam

Dennis

et al. 2016

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

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“…The application of high pressure is effective to raise the CO 2 concentration in water or caustic solutions. Mizuno et al [36] achieved enhanced CO 2 reduction to CH 4 with a pressure increase up to 24.7 atm. Meanwhile, CH 3 OH formed under 9.9 atm, and HCOOH formed at approximately 24.7 atm, which also indicates that the applied pressure and relative CO 2 concentration influences the final products.…”

Section: Uv Light-driven Photocatalysismentioning

confidence: 99%

Full‐Spectrum Solar‐Light‐Activated Photocatalysts for Light–Chemical Energy Conversion

Wang

Sang

et al. 2017

Advanced Energy Materials

258

116

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photocatalysis based on semiconductors represents another route for light energy conversion. This route endows the direct conversion of light energy into oxidation and reduction energy via charge carriers (electrons and holes) generated in the semiconductors. For instance, the photocatalytic degradation of harmful and toxic organic substances, dyes, and chemicals has been considered to be a suitable candidate for removing organic pollution from water, [5][6][7][8] where photooxidation dominates the degradation of the organic molecules. The full process of photocatalytic water splitting into H 2 and O 2 is believed to be promising for generating renewable and green energy, [9,10] and the process includes the photoreduction and photooxidation of water, respectively. The photocatalytic reduction of CO 2 can convert solar energy into chemical energy, stored as CH 4 , CO, CH 3 OH, etc. [11][12][13] These processes can help reduce the pressure of the global warming crisis and supply usable renewable energy. Due to the precise control of photocatalytic reduction and oxidation, photocatalytic molecular synthesis has also attracted much interest, which provides a sustainable pathway for green synthesis. [14][15][16] For an efficient photocatalytic process, solar light harvesting and a redox process based on photogenerated charge carriers are essential steps. Solar light harvesting consists of light absorption and charge carrier excitation steps, which can be expressed as the light utilization efficiency. The efficiency determines the total energy converted from solar light and is mostly determined by the band structure of the semiconductor applied to the photocatalytic process.The photocatalytic process has been extensively studied by examining the response of photocatalysts to UV light, due to its relatively high photonic energy. As is well known, UV light energy amounts to no more than 5% of the solar light energy. Visible light and near-infrared (NIR) light contain approximately 90% of the solar light energy. To utilize solar light in order to solve the environmental and energy crisis, visible light and NIR-light-activated photocatalysts are essential. For decades, many studies have focused on expanding the range over which a photocatalyst can utilize the solar light spectrum. In addition, there are several good reviews summarizing recent progress on UV-vis-light-activated photocatalysts, as well as strategies to improve the photocatalytic efficiency. [17][18][19][20] As is well known, the photonic energy of visible light is low, and that of NIR light is even lower. Photoinduced redox requires an initial amount of energy to activate the process; however, NIR photonic energy may be too low to realize photoinduced The realization of light-chemical energy conversion using solar light is an ideal goal in renewable energy studies. Many reports are concerned with extracting energy from solar light and the use/storage of the converted energy. Due to the progress in solar light absorption with various photocatalysts, the vari...

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“…6A). The highest yield of methane after 24 h of irradiation was observed over the KATI66 (2) catalyst. The yields of methanol were almost the same (Fig.…”

Section: Effect Of Calcination Durationmentioning

confidence: 78%

“…It is important to minimize the influence of transport phenomena during kinetic measurements. The elimination of CO 2 diffusion from the bulk of gas through the gas-liquid interface in a laboratory batch slurry reactor was accomplished by saturating the liquid with pure CO 2 before the reaction started [2,3]. Catalyst loading of 1g .…”

Section: Photocatalytic Reduction Of Co2mentioning

confidence: 99%

“…Therefore, investigators make special effort to find effective methods to reduce CO 2 emissions, and moreover to convert CO 2 into more useful compounds (methane, methanol, ethanol, formic acid etc.). The efficient photocatalytic reduction of CO 2 with H 2 O is one of the most desirable and challenging goals in research around the topic of the environment [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Effect of calcination temperature and calcination time on the kaolinite/tio2 composite for photocatalytic reduction of CO2

Reli¹,

Kočí²,

Matějka³

et al. 2012

GeoScience Engineering

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The kaolinite/TiO 2 composite (60 wt% of TiO 2 ) was prepared by thermal hydrolysis of a raw kaolin suspension in titanyl sulphate and calcined at different temperatures (600, 650 and 700°C) and for different times (1, 2 and 3 h). The obtained samples were characterized by XRPD, N 2 physical adsorption and SEM, and tested for photocatalytic reduction of CO 2 . The different calcination conditions did not influence TiO 2 phase composition, only slightly changed the specific surface area, and significantly affected crystallite size of kaolinite/TiO 2 composite. A higher temperature and longer duration of calcination lead to higher crystallinity of the powder. The photocatalytic results showed that the crystallite size determined the efficiency of kaolinite/TiO 2 photocatalysts. AbstraktKompozit kaolinit/TiO 2 (60 hm% TiO 2 ) byl připraven termální hydrolýzou suspenze surového kaolinu v síranu titanylu a kalcinován při různých teplotách (600, 650 a 700°C) a po různou dobu (1, 2 a 3 h). Získaný vzorek byl charakterizován pomocí XRPD, N 2 fyzikální adsorpcí a SEM, a testován na fotokatalytickou redukci CO 2 . Rozdíl kalcinačních podmínek neovlivnil složení fáze TiO 2 , pouze se mírně pozměnila specifická povrchová plocha a výrazně byla ovlivněna velikost krystalitu kompozitu kaolinit/TiO 2 . Vyšší teplota a delší doba kalcinace vedly k vyšší krystalitě prášku. Fotokatalytické výsledky ukázaly, že velikost krystality určuje účinnost fotokatalyzítoru kaolinit/TiO 2 .

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Effect of CO2 pressure on photocatalytic reduction of CO2 using TiO2 in aqueous solutions

Cited by 111 publications

References 14 publications

RETRACTED: Solar photothermochemical alkane reverse combustion

RETRACTED: Solar photothermochemical alkane reverse combustion

Full‐Spectrum Solar‐Light‐Activated Photocatalysts for Light–Chemical Energy Conversion

Effect of calcination temperature and calcination time on the kaolinite/tio2 composite for photocatalytic reduction of CO2

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