Hydrogen production through photoreforming processes over Cu2O/TiO2 composite materials: A mini-review

Muscetta, Marica; Andreozzi, Roberto; Clarizia, Laura; Somma, Ilaria Di; Marotta, Raffaele

doi:10.1016/j.ijhydene.2020.07.225

Cited by 63 publications

(62 citation statements)

References 124 publications

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“…Cuprous oxide is often used in conjunction with additional functional elements, such as noble metals (e.g., Pt [ 288 , 289 ], Au [ 290 ] or metal copper [ 291 , 292 , 293 , 294 ]) to prepare ternary hybrid photocatalysts. A review that includes several references and experimental results on the use of TiO 2 /Cu 2 O composites for H 2 production through photoreforming processes has been recently published by Marotta and coworkers [ 287 ].…”

Section: Present and Future Trends For Tio 2 -Bmentioning

confidence: 99%

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Charge Carrier Processes and Optical Properties in TiO2 and TiO2-Based Heterojunction Photocatalysts: A Review

Lettieri

Pavone

Fioravanti³

et al. 2021

Materials

149

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Photocatalysis based technologies have a key role in addressing important challenges of the ecological transition, such as environment remediation and conversion of renewable energies. Photocatalysts can in fact be used in hydrogen (H2) production (e.g., via water splitting or photo-reforming of organic substrates), CO2 reduction, pollution mitigation and water or air remediation via oxidation (photodegradation) of pollutants. Titanium dioxide (TiO2) is a “benchmark” photocatalyst, thanks to many favorable characteristics. We here review the basic knowledge on the charge carrier processes that define the optical and photophysical properties of intrinsic TiO2. We describe the main characteristics and advantages of TiO2 as photocatalyst, followed by a summary of historical facts about its application. Next, the dynamics of photogenerated electrons and holes is reviewed, including energy levels and trapping states, charge separation and charge recombination. A section on optical absorption and optical properties follows, including a discussion on TiO2 photoluminescence and on the effect of molecular oxygen (O2) on radiative recombination. We next summarize the elementary photocatalytic processes in aqueous solution, including the photogeneration of reactive oxygen species (ROS) and the hydrogen evolution reaction. We pinpoint the TiO2 limitations and possible ways to overcome them by discussing some of the “hottest” research trends toward solar hydrogen production, which are classified in two categories: (1) approaches based on the use of engineered TiO2 without any cocatalysts. Discussed topics are highly-reduced “black TiO2”, grey and colored TiO2, surface-engineered anatase nanocrystals; (2) strategies based on heterojunction photocatalysts, where TiO2 is electronically coupled with a different material acting as cocatalyst or as sensitizer. Examples discussed include TiO2 composites or heterostructures with metals (e.g., Pt-TiO2, Au-TiO2), with other metal oxides (e.g., Cu2O, NiO, etc.), direct Z-scheme heterojunctions with g-C3N4 (graphitic carbon nitride) and dye-sensitized TiO2.

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Section: Present and Future Trends For Tio 2 -Bmentioning

confidence: 99%

“…The scheme includes possible photogeneration in both TiO 2 and Cu 2 O, where the latter implies the possibility of H 2 generation activated by visible light thanks to the electron transfer from Cu 2 O to TiO 2 . Reprinted with permission from Reference [ 287 ]. Copyright 2020 Hydrogen Energy Publications LLC.…”

Section: Figurementioning

confidence: 99%

Charge Carrier Processes and Optical Properties in TiO2 and TiO2-Based Heterojunction Photocatalysts: A Review

Lettieri

Pavone

Fioravanti³

et al. 2021

Materials

149

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“…To solve these limitations, Cu 2−x O can be combined with TiO 2 within p-n heterojunctions that protect Cu 2−x O against photocorrosion and reduce the charge carrier recombination. The synergism between the two materials is enabled by the appropriate conduction band edges of Cu 2−x O, −1.79 V for Cu 2 O and −1.03 V for CuO, which allows the rapid injection of the photogenerated electrons from the Cu 2−x O to the TiO 2 conduction band [8,[15][16][17][18][19]. Thus, the combination of Cu 2−x O and TiO 2 is regarded as a highly interesting photocatalyst to: (i) stabilize the Cu 2−x O, (ii) boost the overall catalytic activity by extending the light absorption of TiO 2 toward the visible light range and (iii) maximize external quantum yield by a rapid charge separation between the two phases enabled by their adequate band edges.…”

Section: Introductionmentioning

confidence: 99%

Photodehydrogenation of Ethanol over Cu2O/TiO2 Heterostructures

et al. 2021

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The photodehydrogenation of ethanol is a sustainable and potentially cost-effective strategy to produce hydrogen and acetaldehyde from renewable resources. The optimization of this process requires the use of highly active, stable and selective photocatalytic materials based on abundant elements and the proper adjustment of the reaction conditions, including temperature. In this work, Cu2O-TiO2 type-II heterojunctions with different Cu2O amounts are obtained by a one-pot hydrothermal method. The structural and chemical properties of the produced materials and their activity toward ethanol photodehydrogenation under UV and visible light illumination are evaluated. The Cu2O-TiO2 photocatalysts exhibit a high selectivity toward acetaldehyde production and up to tenfold higher hydrogen evolution rates compared to bare TiO2. We further discern here the influence of temperature and visible light absorption on the photocatalytic performance. Our results point toward the combination of energy sources in thermo-photocatalytic reactors as an efficient strategy for solar energy conversion.

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“…[3][4][5] Indeed, several studies report the discovery of successful H 2 synthesis pathways, and many of these routes produced the gas by employing metallic oxides as catalysts, for example, titanium dioxide (TiO 2 ). [6][7][8][9] TiO 2 is a versatile material because it is biocompatible, non-toxic, photostable, insoluble in aqueous medium, corrosion-resistant, and thermally and chemically stable over a wide range of pH. [10][11][12][13] In addition to the extensive use in H 2 production previously mentioned, TiO 2 is frequently employed in pollutant degradation, solar cells, CO 2 conversion, and supercapacitors, among other applications.…”

Section: Introductionmentioning

confidence: 99%

“…In this context, hydrogen gas (H 2 ) production is an excellent alternative for substituting fossil fuels, mainly due to its high energy density and the zero‐emission of gases containing carbon during its application 3–5 . Indeed, several studies report the discovery of successful H 2 synthesis pathways, and many of these routes produced the gas by employing metallic oxides as catalysts, for example, titanium dioxide (TiO 2 ) 6‐9 …”

Section: Introductionmentioning

confidence: 99%

Influence of CVD parameters on Co‐TiO₂/CNT properties: A route to enhance energy harvesting from sunlight

Guaglianoni

García

Basegio

et al. 2021

Int J Applied Ceramic Tech

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Carbon nanotubes (CNTs) have been employed to enhance the photoactivity of titanium dioxide (TiO 2 ). In this work, CNTs were deposited by chemical vapor deposition (CVD) onto the surface of anodized Co-TiO 2 nanotubes. The influence of CVD parameters (time and temperature) on the Co-TiO 2 /CNT structure and properties was investigated. We studied three synthesis times (10, 20, and 30 min) and two synthesis temperatures (700 and 800°C). The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and X-ray diffraction (XRD). The photocurrent performance of the electrodes was determined by linear voltammetry. The results showed the successful formation of Co-TiO 2 /CNT hybrid structures. The shortest synthesis time produced higher quality CNTs. The samples synthesized at 700 and 800°C for 10 min exhibited a current density of 1.13 mA.cm −2 and 7.84 mA.cm −2 , respectively, which is 9 and 65 times greater than the Co-TiO 2 sample. The synergistic effect of the CNT deposition and the crystalline phase composition significantly improved the photoresponse of TiO 2 .The proper choice of synthesis parameters allowed the control of the sample structure, leading to the production of electrodes with better light-harvesting performance.

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Hydrogen production through photoreforming processes over Cu2O/TiO2 composite materials: A mini-review

Cited by 63 publications

References 124 publications

Charge Carrier Processes and Optical Properties in TiO2 and TiO2-Based Heterojunction Photocatalysts: A Review

Charge Carrier Processes and Optical Properties in TiO2 and TiO2-Based Heterojunction Photocatalysts: A Review

Photodehydrogenation of Ethanol over Cu2O/TiO2 Heterostructures

Influence of CVD parameters on Co‐TiO₂/CNT properties: A route to enhance energy harvesting from sunlight

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Hydrogen production through photoreforming processes over Cu2O/TiO2 composite materials: A mini-review

Cited by 63 publications

References 124 publications

Charge Carrier Processes and Optical Properties in TiO2 and TiO2-Based Heterojunction Photocatalysts: A Review

Charge Carrier Processes and Optical Properties in TiO2 and TiO2-Based Heterojunction Photocatalysts: A Review

Photodehydrogenation of Ethanol over Cu2O/TiO2 Heterostructures

Influence of CVD parameters on Co‐TiO2/CNT properties: A route to enhance energy harvesting from sunlight

Contact Info

Product

Resources

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Influence of CVD parameters on Co‐TiO₂/CNT properties: A route to enhance energy harvesting from sunlight