1
|
Liu C, Wang C, Wang R, Li D, Jin D, Ohtani B, Liu B, Ma H, Du J, Liu Y, Zhang X. Ultrasonic-Induced Surface Disordering Promotes Photocatalytic Hydrogen Evolution of TiO 2. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39191507 DOI: 10.1021/acsami.4c10977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
Surface disordering has been considered an effective strategy for tailoring the charge separation and surface chemistry of semiconductor photocatalysts. A simple but reliable method to create surface disordering is, therefore, urgently needed for the development of high-performance semiconductor photocatalysts and their practical applications. Herein, we report that the ultrasonic processing, which is commonly employed in the dispersion of photocatalysts, can induce the surface disordering of TiO2 and significantly promote its performance for photocatalytic hydrogen evolution. A 40 min ultrasonic treatment of TiO2 (Degussa P25) enhances the photocatalytic hydrogen production by 42.7 times, achieving a hydrogen evolution rate of 1425.4 μmol g-1 h-1 without any cocatalyst. Comprehensive structural, spectral, and electrochemical analyses reveal that the ultrasonic treatment induces the surface disordering of TiO2, and consequently reduces the density of deep electron traps, extends the separation of photogenerated charges, and facilitates the hydrogen evolution reaction relative to oxygen reduction. The ultrasonic treatment manifests a more pronounced effect on disordering the surface of anatase than rutile, agreeing well with the enhanced photocatalysis of anatase rather than rutile. This study demonstrates that ultrasonic-induced surface disordering could be an effective strategy for the activation of photocatalysts and might hold significant implications for the applications in photocatalytic hydrogen evolution, small molecule activation, and biomass conversion.
Collapse
Affiliation(s)
- Chunyao Liu
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Changhua Wang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Rui Wang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Dashuai Li
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Dexin Jin
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Baoshun Liu
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070, China
| | - He Ma
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Jinglun Du
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Yichun Liu
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Xintong Zhang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, Changchun 130024, China
| |
Collapse
|
2
|
Wang R, Che G, Wang C, Liu C, Liu B, Ohtani B, Liu Y, Zhang X. Alcohol Plasma Processed Surface Amorphization for Photocatalysis. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rui Wang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, People’s Republic of China
| | - Guangshun Che
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, People’s Republic of China
| | - Changhua Wang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, People’s Republic of China
| | - Chunyao Liu
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, People’s Republic of China
| | - Baoshun Liu
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070, People’s Republic of China
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yichun Liu
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, People’s Republic of China
| | - Xintong Zhang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, People’s Republic of China
| |
Collapse
|
3
|
Reversed double-beam photoacoustic spectroscopic analysis of photoinduced change in absorption of cellulose fibres. Sci Rep 2022; 12:14475. [PMID: 36008458 PMCID: PMC9411129 DOI: 10.1038/s41598-022-18749-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/18/2022] [Indexed: 11/20/2022] Open
Abstract
Photoabsorption properties of cellulose fibres under continuous and modulated irradiation were investigated in situ by the use of reversed double-beam photoacoustic spectroscopy (RDB-PAS). This photoacoustic (PA) measurement enabled observation of ultraviolet- and visible light-induced, electron trap filling, and reductive change on the surface of the fibres. Energy-resolved measurements and analysis of the kinetics of photoinduced de-excitation suggested that electrons that accumulated in the different cellulose crystalline phases had moderate reactivity toward molecular oxygen. Saturation limits of the intensities of the PA and RDB-PAS signals under de-aerated conditions in the presence of surface-adsorbed methanol were estimated for softwood and hardwood cellulose samples. The results suggest that the RDB-PAS technique is a feasible method for the estimation of the electron trap distribution, which is a potential measure of the density of crystalline cellulose defects.
Collapse
|
4
|
Reduction of nitrate to ammonia using photocatalytically accumulated electrons on titanium(IV) oxide in a time-separated redox reaction. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
5
|
Yoshiiri K, Karabiyik B, Wang K, Wei Z, Colbeau-Justin C, Kowalska E. The property-governed activity of silver-modified titania photocatalysts: The influence of titania matrix. J Chem Phys 2022; 156:244706. [DOI: 10.1063/5.0097762] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Commercial titania photocatalysts were modified with silver nanoparticles (NPs) by the photodeposition method in the presence/absence of methanol. The obtained photocatalysts were characterized by XRD, XPS, diffuse reflectance spectroscopy, STEM, and time-resolved microwave conductivity (TRMC) methods. The photocatalytic activity was tested under UV/vis irradiation for (i) methanol dehydrogenation (during silver deposition), (ii) oxygen evolution with in situ silver deposition, and (iii) oxidative decomposition of acetic acid, as well as under vis irradiation for 2-propanol oxidation. The action spectra of 2-propanol oxidation were also performed. It has been confirmed that modification of titania with silver causes significant improvement of photocatalytic activity under both UV and vis irradiation as silver works as an electron scavenger (TRMC data) and vis activator (possibly by an energy transfer mechanism). The obtained activities differ between titania samples significantly, suggesting that the type of crystalline phase, particle/crystallite sizes, and electron traps’ density are crucial for both the properties of formed silver deposits and resultant photocatalytic activity. It might be concluded that, under UV irradiation, (i) high crystallinity and large specific surface area are recommended for rutile- and anatase-rich samples, respectively, during hydrogen evolution, (ii) mixed crystalline phases cause a high rate of oxygen evolution from water, and (iii) anatase phase with fine silver NPs results in efficient decomposition of acetic acid, whereas under vis irradiation the aggregated silver NPs (broad localized surface plasmon resonance peak) on the rutile phase are promising for oxidation reactions.
Collapse
Affiliation(s)
- Kenta Yoshiiri
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
- Institute for Catalysis (ICAT), Hokkaido University, Sapporo, Japan
| | - Baris Karabiyik
- Institute for Catalysis (ICAT), Hokkaido University, Sapporo, Japan
| | - Kunlei Wang
- Institute for Catalysis (ICAT), Hokkaido University, Sapporo, Japan
- Northwest Research Institute, Co. Ltd. of C.R.E.C., Lanzhou, China
| | - Zhishun Wei
- Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan, People's Republic of China
| | | | - Ewa Kowalska
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
- Institute for Catalysis (ICAT), Hokkaido University, Sapporo, Japan
| |
Collapse
|
6
|
Sakuna P, Ketwong P, Ohtani B, Trakulmututa J, Kobkeatthawin T, Luengnaruemitchai A, Smith SM. The Influence of Metal-Doped Graphitic Carbon Nitride on Photocatalytic Conversion of Acetic Acid to Carbon Dioxide. Front Chem 2022; 10:825786. [PMID: 35402383 PMCID: PMC8983859 DOI: 10.3389/fchem.2022.825786] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Metal-doped graphitic carbon nitride (MCN) materials have shown great promise as effective photocatalysts for the conversion of acetic acid to carbon dioxide under UV–visible irradiation and are superior to pristine carbon nitride (g-C3N4, CN). In this study, the effects of metal dopants on the physicochemical properties of metal-doped CN samples (Fe-, Cu-, Zn-, FeCu-, FeZn-, and CuZn-doped CN) and their catalytic activity in the photooxidation of acetic acid were investigated and discussed for their correlation, especially on their surface and bulk structures. The materials in the order of highest to lowest photocatalytic activity are FeZn_CN, FeCu_CN, Fe_CN, and Cu_CN (rates of CO2 evolution higher than for CN), followed by Zn_CN, CuZn_CN, and CN (rates of CO2 evolution lower than CN). Although Fe doping resulted in the extension of the light absorption range, incorporation of metals did not significantly alter the crystalline phase, morphology, and specific surface area of the CN materials. However, the extension of light absorption into the visible region on Fe doping did not provide a suitable explanation for the increase in photocatalytic efficiency. To further understand this issue, the materials were analyzed using two complementary techniques, reversed double-beam photoacoustic spectroscopy (RDB-PAS) and electron spin resonance spectroscopy (ESR). The FeZn_CN, with the highest electron trap density between 2.95 and 3.00 eV, afforded the highest rate of CO2 evolution from acetic acid photodecomposition. All Fe-incorporated CN materials and Cu-CN reported herein can be categorized as high activity catalysts according to the rates of CO2 evolution obtained, higher than 0.15 μmol/min−1, or >1.5 times higher than that of pristine CN. Results from this research are suggestive of a correlation between the rate of CO2 evolution via photocatalytic oxidation of acetic acid with the threshold number of free unpaired electrons in CN-based materials and high electron trap density (between 2.95 and 3.00 eV).
Collapse
Affiliation(s)
- Pichnaree Sakuna
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
| | | | - Bunsho Ohtani
- Institute for Catalysis, Hokkaido University, Sapporo, Japan
- *Correspondence: Bunsho Ohtani, ; Siwaporn Meejoo Smith,
| | - Jirawat Trakulmututa
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
| | - Thawanrat Kobkeatthawin
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
| | | | - Siwaporn Meejoo Smith
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
- *Correspondence: Bunsho Ohtani, ; Siwaporn Meejoo Smith,
| |
Collapse
|
7
|
Ohtani B, Takashima M. Happy photocatalysts and unhappy photocatalysts: electron trap-distribution analysis for metal oxide-sample identification. Catal Sci Technol 2022. [DOI: 10.1039/d1cy01955d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An attempt to identify inorganic solids, such as metal oxides, using ERDT (energy-resolved distribution of electron traps)/CBB (conduction-band bottom) patterns, measured by reversed double-beam spectroscopy, as a “fingerprint” is introduced.
Collapse
Affiliation(s)
- Bunsho Ohtani
- Institute for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
| | - Mai Takashima
- Institute for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
| |
Collapse
|
8
|
Kojima R, Ohtani B, Tada H. Photocatalytic Activity of Radial Rutile Titanium(IV) Oxide Microspheres for Aerobic Oxidation of Organics. Chemphyschem 2021; 23:e202100793. [PMID: 34918451 DOI: 10.1002/cphc.202100793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/08/2021] [Indexed: 11/07/2022]
Abstract
Radial rutile TiO2 nanorod homomesocrystals (TiO2 -NR HOMCs) or the so-called "sea urchin-like TiO2 microspheres" were synthesized by using a hydrothermal method. TiO2 -NR HOMCs show photocatalytic activity for aerobic oxidative degradation of 2-naphthol under irradiation of UV- and visible light. Furthermore, extremely small iron oxide clusters were formed on the surface of TiO2 -NR HOMCs (FeOx /TiO2 -NR HOMCs) by the chemisorption-calcination technique to reduce the band gap. The FeOx -surface modification gives rise to drastic enhancement of the UV- and visible-light activity. Reversed double-beam photoacoustic spectroscopy measurements were performed for TiO2 -NR HOMCs and FeOx /TiO2 -NR HOMCs to obtain the ERDT (energy-resolved distribution of electron traps)/CBB (conduction-band bottom) patterns. The ERDT/CBB pattern of TiO2 -NR HOMCs consists of two components derived from rutile (C1) and amorphous TiO2 (C2). In the pattern, the surface electron traps in C2 exist near the CBB to be removed by the FeOx -surface modification. By taking this finding into consideration, the striking surface modification effect is ascribable to the electrocatalytic activity (or the action as an electron reservoir) of the FeOx clusters for multiple ORR, the suppression of recombination, and the increase in the visible-light harvesting efficiency.
Collapse
Affiliation(s)
- Ryota Kojima
- Graduate School of Science and Engineering, Kindai University, 3-4-1, Kowakae, 577-8502, Higashi-Osaka, Osaka, Japan
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan.,Institute for Catalysis, Hokkaido University, 001-0021, Sapporo, Hokkaido, Japan
| | - Hiroaki Tada
- Graduate School of Science and Engineering, Kindai University, 3-4-1, Kowakae, 577-8502, Higashi-Osaka, Osaka, Japan
| |
Collapse
|
9
|
Chen G, Takashima M, Ohtani B. Direct Amorphous-structure Analysis: How are Surface/Bulk Structure and Activity of Titania Photocatalyst Particles Changed by Milling? CHEM LETT 2021. [DOI: 10.1246/cl.200825] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Guangyi Chen
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Mai Takashima
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
| |
Collapse
|
10
|
Nagakawa H, Nagata M. Elucidating the Factors Affecting Hydrogen Production Activity Using a CdS/TiO 2 Type-II Composite Photocatalyst. ACS OMEGA 2021; 6:4395-4400. [PMID: 33644552 PMCID: PMC7906583 DOI: 10.1021/acsomega.0c05749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
CdS/TiO2 is a composite photocatalyst that has been studied over many years and in which electron transfer from CdS to TiO2 is believed to lead to high photocatalytic activity. However, most reports on improved activity involve hydrogen production in the presence of a sulfide reducing agent. In this study, we comprehensively examined the effects of electron transfer, hydrogen overvoltage, substrate adsorption, and the cocatalyst from relationships between hydrogen production ability and the total number of trapped electrons in the presence of various reducing agents. As a result, we clarified that the electron transfer between CdS and TiO2 does not necessarily lead to high activity. We showed that the composite photocatalyst needs to be designed for the intended purpose and that evaluating the hydrogen production ability using sacrificial reagents provides insufficient information for use in an actual environment.
Collapse
Affiliation(s)
- Haruki Nagakawa
- Department of Industrial Chemistry, Graduate School of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-cho, Shinjuku-ku, Tokyo 162-0826, Japan
| | - Morio Nagata
- Department of Industrial Chemistry, Graduate School of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-cho, Shinjuku-ku, Tokyo 162-0826, Japan
| |
Collapse
|
11
|
Shen Y, Nitta A, Takashima M, Ohtani B. Do Particles Interact Electronically? —Proof of Interparticle Charge-transfer Excitation between Adjoined Anatase and Rutile Particles. CHEM LETT 2021. [DOI: 10.1246/cl.200636] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yang Shen
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Akio Nitta
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Mai Takashima
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
| |
Collapse
|
12
|
Velo-Gala I, Torres-Pinto A, Silva CG, Ohtani B, Silva AMT, Faria JL. Graphitic carbon nitride photocatalysis: the hydroperoxyl radical role revealed by kinetic modelling. Catal Sci Technol 2021. [DOI: 10.1039/d1cy01657a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The behaviour of graphitic carbon nitride photocatalysis for phenol removal and H2O2 evolution was fully analysed by kinetic modelling, rediscovering the contribution of oxygen, reactive oxygen species, photogenerated holes and intermediate products.
Collapse
Affiliation(s)
- Inmaculada Velo-Gala
- Laboratory of Separation and Reaction Engineering – Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Porto 4200-465, Portugal
| | - André Torres-Pinto
- Laboratory of Separation and Reaction Engineering – Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Porto 4200-465, Portugal
| | - Cláudia G. Silva
- Laboratory of Separation and Reaction Engineering – Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Porto 4200-465, Portugal
| | - Bunsho Ohtani
- Institute for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
| | - Adrián M. T. Silva
- Laboratory of Separation and Reaction Engineering – Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Porto 4200-465, Portugal
| | - Joaquim L. Faria
- Laboratory of Separation and Reaction Engineering – Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Porto 4200-465, Portugal
| |
Collapse
|
13
|
Vis-Responsive Copper-Modified Titania for Decomposition of Organic Compounds and Microorganisms. Catalysts 2020. [DOI: 10.3390/catal10101194] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Seven commercial titania (titanium(IV) oxide; TiO2) powders with different structural properties and crystalline compositions (anatase/rutile) were modified with copper by two variants of a photodeposition method, i.e., methanol dehydrogenation and water oxidation. The samples were characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Although zero-valent copper was deposited on the surface of titania, oxidized forms of copper, post-formed in ambient conditions, were also detected in dried samples. All samples could absorb visible light (vis), due to localized surface plasmon resonance (LSPR) of zero-valent copper and by other copper species, including Cu2O, CuO and CuxO (x:1-2). The photocatalytic activities of samples were investigated under both ultraviolet (UV) and visible light irradiation (>450 nm) for oxidative decomposition of acetic acid. It was found that titania modification with copper significantly enhanced the photocatalytic activity, especially for anatase samples. The prolonged irradiation (from 1 to 5 h) during samples’ preparation resulted in aggregation of copper deposits, thus being detrimental for vis activity. It is proposed that oxidized forms of copper are more active under vis irradiation than plasmonic one. Antimicrobial properties against bacteria (Escherichia coli) and fungi (Aspergillus niger) under vis irradiation and in the dark confirmed that Cu/TiO2 exhibits a high antibacterial effect, mainly due to the intrinsic activity of copper species.
Collapse
|
14
|
Sano K, Kuttassery F, Shimada T, Ishida T, Takagi S, Ohtani B, Yamakata A, Honma T, Tachibana H, Inoue H. Optically Transparent Colloidal Dispersion of Titania Nanoparticles Storable for Longer than One Year Prepared by Sol/Gel Progressive Hydrolysis/Condensation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:44743-44753. [PMID: 32915534 DOI: 10.1021/acsami.0c12951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The molecular catalyst sensitized system (MCSS), where an excited molecular catalyst adsorbed on a semiconductor such as TiO2 injects electrons to the conduction band of the semiconductor leading to hydrogen evolution/CO2 reduction coupled with an oxidation of water on the molecular catalyst, has been one of the most probable candidates in the approach to artificial photosynthesis. For a full utilization of visible light, however, a serious light scattering of the aqueous suspension of TiO2 in the visible region, which is generally experienced, should be avoided. Here, we report a preparation of optically transparent colloidal dispersion of TiO2 by the sol/gel reaction of TiCl4 through progressive hydrolysis/condensation under the basic condition without any calcination processes. The TiO2 nanoparticles (TiO2(NPs)) obtained were characterized as an amorphous particle (∼10-15 nm) having a microcrystal domain of anatase within several nm by XRD, Raman spectroscopies, XRF, XAFS, TG/DTA, and HRTEM, respectively. The energy-resolved distribution of carrier electron traps in TiO2(NPs) as a fingerprint of TiO2 was characterized through reversed double-beam photo-acoustic spectroscopy to have a close similarity to that of TiO2(ST-01) as well as the observation of carrier traps by transient absorption spectroscopy. Though the powder TiO2(NP) itself was not dispersed well in aqueous solution, the wet TiO2(NPs) as prepared before being dried up provided a completely transparent aqueous dispersion under the acidic condition (1 M HCl). Addition of methanol enabled the colloidal dispersion (TiO2(NPs, MeOH/H2O, 0.1 M HCl)) to keep the optical transparency for longer than 1 year (550 days), which is the first example of TiO2 dispersion storable for such a long period. TiO2(NPs, MeOH/H2O) exhibited a moderate photocatalytic reactivity of H2 evolution with a quantum yield of ∼2.6% upon 365 nm light irradiation. An optically transparent thin film of TiO2(NPs, MeOH/H2O) was also successfully prepared on a glass plate to exhibit an enhanced hydrophilicity upon UV light irradiation.
Collapse
Affiliation(s)
- Keito Sano
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Fazalurahman Kuttassery
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Tetsuya Shimada
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Tamao Ishida
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Shinsuke Takagi
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Bunsho Ohtani
- Institute for catalysis Hokkaido University, North 21, West 10, Sapporo 001-0021, Japan
| | - Akira Yamakata
- Toyota Technological Institute, 2-12-1, Hisakata, Tempaku, Nagoya 468-8511, Japan
| | - Tetsuo Honma
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Hiroshi Tachibana
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Haruo Inoue
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| |
Collapse
|
15
|
Yu F, Wang C, Li Y, Ma H, Wang R, Liu Y, Suzuki N, Terashima C, Ohtani B, Ochiai T, Fujishima A, Zhang X. Enhanced Solar Photothermal Catalysis over Solution Plasma Activated TiO 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000204. [PMID: 32832348 PMCID: PMC7435248 DOI: 10.1002/advs.202000204] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/25/2020] [Indexed: 05/22/2023]
Abstract
Colored wide-bandgap semiconductor oxides with abundant mid-gap states have long been regarded as promising visible light responsive photocatalysts. However, their catalytic activities are hampered by charge recombination at deep level defects, which constitutes the critical challenge to practical applications of these oxide photocatalysts. To address the challenge, a strategy is proposed here that includes creating shallow-level defects above the deep-level defects and thermal activating the migration of trapped electrons out of the deep-level defects via these shallow defects. A simple and scalable solution plasma processing (SPP) technique is developed to process the presynthesized yellow TiO2 with numerous oxygen vacancies (Ov), which incorporates hydrogen dopants into the TiO2 lattice and creates shallow-level defects above deep level of Ov, meanwhile retaining the original visible absorption of the colored TiO2. At elevated temperature, the SPP-treated TiO2 exhibits a 300 times higher conversion rate for CO2 reduction under solar light irradiation and a 7.5 times higher removal rate of acetaldehyde under UV light irradiation, suggesting the effectiveness of the proposed strategy to enhance the photoactivity of colored wide-bandgap oxides for energy and environmental applications.
Collapse
Affiliation(s)
- Fei Yu
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Changhua Wang
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Yingying Li
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - He Ma
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Rui Wang
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Yichun Liu
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Norihiro Suzuki
- Photocatalysis International Research CenterResearch Institute for Science & TechnologyTokyo University of Science2641 YamazakiNodaChiba278‐8510Japan
| | - Chiaki Terashima
- Photocatalysis International Research CenterResearch Institute for Science & TechnologyTokyo University of Science2641 YamazakiNodaChiba278‐8510Japan
| | - Bunsho Ohtani
- Graduate School of Environmental ScienceHokkaido UniversitySapporo060‐0810Japan
| | - Tsuyoshi Ochiai
- Materials Analysis GroupKawasaki Technical Support DepartmentLocal Independent Administrative Agency Kanagawa Institute of industrial Science and Technology (KISTEC)Kanagawa213‐0012Japan
| | - Akira Fujishima
- Photocatalysis International Research CenterResearch Institute for Science & TechnologyTokyo University of Science2641 YamazakiNodaChiba278‐8510Japan
| | - Xintong Zhang
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| |
Collapse
|
16
|
Nagashima H, Trébosc J, Kon Y, Sato K, Lafon O, Amoureux JP. Observation of Low-γ Quadrupolar Nuclei by Surface-Enhanced NMR Spectroscopy. J Am Chem Soc 2020; 142:10659-10672. [DOI: 10.1021/jacs.9b13838] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Hiroki Nagashima
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Julien Trébosc
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, UCCS - Unité de Catalyse et de Chimie du Solide, F-59000 Lille, France
- Univ. Lille, CNRS-2638, Fédération Chevreul, F-59000 Lille, France
| | - Yoshihiro Kon
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Kazuhiko Sato
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Olivier Lafon
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, UCCS - Unité de Catalyse et de Chimie du Solide, F-59000 Lille, France
- Institut Universitaire de France, 1 rue Descartes, F-75231 Paris, France
| | - Jean-Paul Amoureux
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, UCCS - Unité de Catalyse et de Chimie du Solide, F-59000 Lille, France
- Bruker Biospin, 34 rue de l’industrie, F-67166 Wissembourg, France
- Riken NMR Science and Development Division, Yokohama, 230-0045 Kanagawa, Japan
| |
Collapse
|
17
|
Yu F, Wang C, Ma H, Song M, Li D, Li Y, Li S, Zhang X, Liu Y. Revisiting Pt/TiO 2 photocatalysts for thermally assisted photocatalytic reduction of CO 2. NANOSCALE 2020; 12:7000-7010. [PMID: 32103213 DOI: 10.1039/c9nr09743k] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Artificial photosynthesis by a semiconductor-oxide-based photocatalysis is presently challenging due to low CO2 conversion rates and poor product selectivity. To promote CO2 reduction, Pt/TiO2 has been deemed as a classic photocatalyst. In this study, we restudy Pt/TiO2 for the thermally assisted photocatalytic reduction of CO2 and reveal a different story between photocatalysis and photothermal catalysis. For example, when using disordered Pt/TiO2-x, the CO2 conversion via photocatalysis at 298 K is not impressive. However, when the system temperature is increased to 393 K, the CO2 conversion rate is significantly enhanced by a factor of 155 as compared to that obtainable from pristine TiO2; further, surprisingly high selectivity of CH4 (87.5%) could be achieved. Thermally coupled photocatalysis yields the enhanced evolution of H2 side products over Pt (4.06 nm)/TiO2 and promoted H2 splitting over Pt (2.33 nm)/TiO2, which is seldom observed in conventional Pt/TiO2 photocatalysis. The synergy of improved charge separation at the Pt/TiO2-x interface induced by surface disordering and accelerated H2 consumption near smaller Pt nanoparticles by thermal assistance are believed to be critically important for the simultaneous enhancement of CO2 conversion rates and CH4 product selectivity. This study inspires revisiting not only Pt/TiO2 but also reactivating other semiconductor-oxide-based photocatalysts for use in thermally assisted photocatalysis.
Collapse
Affiliation(s)
- Fei Yu
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China.
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Chuaicham C, Karthikeyan S, Song JT, Ishihara T, Ohtani B, Sasaki K. Importance of ZnTiO 3 Phase in ZnTi-Mixed Metal Oxide Photocatalysts Derived from Layered Double Hydroxide. ACS APPLIED MATERIALS & INTERFACES 2020; 12:9169-9180. [PMID: 32064859 DOI: 10.1021/acsami.9b18785] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, ZnTi-mixed metal oxides (ZTM), such as ZnTiO3, were synthesized from ZnTi layered double hydroxides by varying the molar ratio of Zn/Ti, calcination temperatures, and synthesis methods (hydrothermal or reflux). The surface electronic characteristics of ZTM were investigated by the energy-resolved distribution of electron traps (ERDTs) using reversed double-beam photoacoustic spectroscopy. The ZTM samples obtained by conducting hydrothermal synthesis at 500 °C showed similar ERDT patterns independent of the molar ratio of Zn/Ti, although ZnTiO3 phase was not observed in the X-ray diffraction pattern, when the Zn/Ti ratio was high. When the ERDT patterns demonstrated a high electron accumulation level near the conduction band bottom in hydrothermal products at 500 °C, a higher photocatalytic phenol degradation efficiency was observed due to the formation of ZnTiO3 phase. This suggested that the product with the high Zn/Ti molar ratio (Zn/Ti = 6) constituted amorphous ZnTiO3.The enhanced photocatalytic performance of ZTM could be attributed to the heterojunction of electrons among ZnO, TiO2, and ZnTiO3, which enabled electron transfer in the composites, prevented charge recombination, and promoted a wider visible light adsorption by ZnTiO3 phase irrespective of its crystallinity.
Collapse
Affiliation(s)
- Chitiphon Chuaicham
- Department of Earth Resources Engineering, Faculty of Engineering , Kyushu University , 744 Motooka, Nishiku , Fukuoka 819-0395 , Japan
| | - Sekar Karthikeyan
- Department of Earth Resources Engineering, Faculty of Engineering , Kyushu University , 744 Motooka, Nishiku , Fukuoka 819-0395 , Japan
| | - Jun Tae Song
- Department of Applied Chemistry, Faculty of Engineering , Kyushu University , 744 Motooka, Nishiku , Fukuoka 819-0395 , Japan
- International Institute for Carbon-Neutral Energy Research (I2CNER) , 744 Motooka, Nishiku , Fukuoka 819-0395 , Japan
| | - Tatsumi Ishihara
- Department of Applied Chemistry, Faculty of Engineering , Kyushu University , 744 Motooka, Nishiku , Fukuoka 819-0395 , Japan
- International Institute for Carbon-Neutral Energy Research (I2CNER) , 744 Motooka, Nishiku , Fukuoka 819-0395 , Japan
| | - Bunsho Ohtani
- Institute for Catalysis , Hokkaido University , Sapporo 001-0021 , Japan
| | - Keiko Sasaki
- Department of Earth Resources Engineering, Faculty of Engineering , Kyushu University , 744 Motooka, Nishiku , Fukuoka 819-0395 , Japan
- Institute for Catalysis , Hokkaido University , Sapporo 001-0021 , Japan
| |
Collapse
|
19
|
Carbon/Graphene-Modified Titania with Enhanced Photocatalytic Activity under UV and Vis Irradiation. MATERIALS 2019; 12:ma12244158. [PMID: 31835760 PMCID: PMC6947090 DOI: 10.3390/ma12244158] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/28/2019] [Accepted: 12/09/2019] [Indexed: 11/18/2022]
Abstract
Laser synthesis was used for one-step synthesis of titania/graphene composites (G-TiO2 (C)) from a suspension of 0.04 wt% commercial reduced graphene oxide (rGO) dispersed in liquid titanium tetraisopropoxide (TTIP). Reference titania sample (TiO2(C)) was prepared by the same method without graphene addition. Both samples and commercial titania P25 were characterized by various methods and tested under UV/vis irradiation for oxidative decomposition of acetic acid and dehydrogenation of methanol (with and without Pt co-catalyst addition), and under vis irradiation for phenol degradation and inactivation of Escherichia coli. It was found that both samples (TiO2(C) and G-TiO2(C)) contained carbon resulting from TTIP and C2H4 (used as a synthesis sensitizer), which activated titania towards vis activity. The photocatalytic activity under UV/vis irradiation was like that by P25. The highest activity of TiO2(C) sample for acetic acid oxidation was probably caused by its surface enrichment with hydroxyl groups. G-TiO2(C) was the most active for methanol dehydrogenation in the absence of platinum (ca. five times higher activity than that by TiO2(C) and P25), suggesting that graphene works as a co-catalyst for hydrogen evolution. High activity under both UV and vis irradiation for decomposition of organic compounds, hydrogen evolution and inactivation of bacteria suggests that laser synthesis allows preparation of cheap (carbon-modified) and efficient photocatalysts for broad environmental applications.
Collapse
|
20
|
Correlation of the Photocatalytic Activities of Cu, Ce and/or Pt-Modified Titania Particles with their Bulk and Surface Structures Studied by Reversed Double-Beam Photoacoustic Spectroscopy. Catalysts 2019. [DOI: 10.3390/catal9121010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Modified titania photocatalyst powder samples were prepared using the sol-gel method for copper (Cu) and cerium (Ce) doping and impregnation for platinum (Pt) loading. Their bulk crystalline structures were investigated using X-ray diffractometry (XRD) with the Rietveld analysis. The surface/bulk structure, surface properties, and morphologies were observed using reversed double-beam photoacoustic spectroscopy (RDB-PAS), nitrogen adsorption, and scanning electron microscopy, respectively. The results from the XRD revealed that all samples were mainly anatase (ca. 80% or higher) with small amounts of rutile and non-crystalline components. The specific surface areas of all samples were in the range of 115–155 m2 g−1. Ce and Cu species were mainly distributed, while Pt was potentially loaded as a partially oxidized form on the titania surface. The results from the RDB-PAS indicated the changing of the energy-resolved distribution of electron traps (ERDT) from the original titania surface upon doping of the metals (Cu, Ce, and Pt), which altered their catalytic activities. The metals photocatalytic activities with UV irradiation were measured in two representative reactions; (a) CO2 evolution from acetic acid under the aerobic condition and (b) H2 evolution from deaerated aqueous methanol. In reaction (a), the Cu and/or Ce modification gave almost the same or slightly lower activity compared to the non-modified titania samples, while platinum loading yielded ca. 5–6 times higher activity. For reaction (b), the photocatalytic tests were divided into two sets; without (b1) and with (b2) Pt deposition during the reaction. Similar enhancements of activity from the Pt loading sample (and by Cu modification) were observed in reaction (b1) without in-situ platinum deposition, while the unmodified and Ce-doped samples were almost inactive. For the activities of reaction (b2) with in-situ platinum deposition, the unmodified samples showed the highest activity while the Cu-modified samples showed significantly lower activity.
Collapse
|
21
|
Walenta CA, Tschurl M, Heiz U. Introducing catalysis in photocatalysis: What can be understood from surface science studies of alcohol photoreforming on TiO 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:473002. [PMID: 31342942 DOI: 10.1088/1361-648x/ab351a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Mechanisms in heterogeneous photocatalysis have traditionally been interpreted by the band-structure model and analogously to electrochemistry. This has led to the establishment of 'band-engineering' as a leading principle for the discovery of more efficient photocatalysts. In such a picture, mainly thermodynamic aspects are taken into account, while kinetics are often ignored. This holds in particular for chemical kinetics, which are, other than those for charge carrier dynamics, often not at all considered for the interpretation of the catalysts' photocatalytic performance. However, while being usually neglected in photocatalyis, they are a traditional and powerful tool in thermal catalysis and are still applied with great success in this field. While surface science studies made substantial contributes to thermal catalysis, analogous studies in heterogeneous photocatalysis still play only a minor role. In this review, the authors show that the photo-physics of defined materials in well-defined environments can be correlated with photochemical events on a surface, highlighting the importance of well-characterized semiconductors for the interpretation of mechanisms in heterogeneous photochemistry. The work focuses on contributions from surface science, which were obtained for the model system of a titania single crystal and alcohol photo-reforming. It is demonstrated that only surface science studies have so far enabled the elucidation of molecularly precise reaction mechanisms, the determination of reaction intermediates and assignment of reactive sites. As the identification of these properties remain major prerequisites for a breakthrough in photocatalysis research, the work also discusses the implications of the findings for applied systems. In general, the results from surface science demonstrate that photocatalytic systems shall also be approached by a perspective originating from heterogeneous catalysis rather than solely from an electrochemical point of view.
Collapse
|
22
|
Nitta A, Takashima M, Murakami N, Takase M, Ohtani B. Reversed double-beam photoacoustic spectroscopy of metal-oxide powders for estimation of their energy-resolved distribution of electron traps and electronic-band structure. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2017.12.160] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|