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Deitermann M, Sato T, Haver Y, Schnegg A, Muhler M, Mei BT. Mechanistic understanding of the thermal-assisted photocatalytic oxidation of methanol-to-formaldehyde with water vapor over Pt/SrTiO 3. Phys Chem Chem Phys 2024; 26:14960-14969. [PMID: 38739165 DOI: 10.1039/d4cp01106f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Anaerobic thermal-assisted photocatalytic methanol conversion in the gas phase in the presence of water vapor has been suggested as an interesting way to generate formaldehyde as a valuable coupled product in addition to H2 production. Here, the reaction mechanism and photocatalyst deactivation are investigated in detail using in situ diffuse reflectance infrared fourier transform (DRIFTS) and electron paramagnetic resonance (EPR) spectroscopy. EPR shows that paramagnetic oxygen vacancies are not involved in the reaction mechanism over undoped SrTiO3. Instead, on an optimized 0.1 wt% Pt/SrTiO3 photocatalyst, methoxy species are formed by dissociative adsorption of methanol leading to formaldehyde formation while the formation of CO, CO2 (via a formate intermediate) and methyl formate occurs through three concurrent reactions from formyl species. Our findings suggest that CO adsorbed on Pt is a spectator species not perturbing the reaction kinetics, and deactivation is shown to be strongly correlated with the accumulation of formate groups on SrTiO3, which is more pronounced at high reaction temperatures. The mechanistic understanding provided here forms the basis for the further optimization of photocatalysts to increase methanol conversion and improve formaldehyde selectivity.
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Affiliation(s)
- Michel Deitermann
- Laboratory of Industrial Chemistry, Ruhr University Bochum, 44780 Bochum, Germany.
- Max Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Takuma Sato
- Max Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Yannik Haver
- Laboratory of Industrial Chemistry, Ruhr University Bochum, 44780 Bochum, Germany.
| | - Alexander Schnegg
- Max Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Martin Muhler
- Laboratory of Industrial Chemistry, Ruhr University Bochum, 44780 Bochum, Germany.
- Max Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Bastian Timo Mei
- Laboratory of Industrial Chemistry, Ruhr University Bochum, 44780 Bochum, Germany.
- Photocatalytic Synthesis Group, Faculty of Science & Technology of the University of Twente, PO Box 217, Enschede, The Netherlands
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Majrik K, Pászti Z, Korecz L, Mihály J, May Z, Németh P, Cannilla C, Bonura G, Frusteri F, Tompos A, Tálas E. Effect of the Microstructure of the Semiconductor Support on the Photocatalytic Performance of the Pt-PtO x/TiO 2 Catalyst System. MATERIALS (BASEL, SWITZERLAND) 2021; 14:943. [PMID: 33671227 PMCID: PMC7921961 DOI: 10.3390/ma14040943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 11/16/2022]
Abstract
The influence of the semiconductor microstructure on the photocatalytic behavior of Pt-PtOx/TiO2 catalysts was studied by comparing the methanol-reforming performance of systems based on commercial P25 or TiO2 from sol-gel synthesis calcined at different temperatures. The Pt co-catalyst was deposited by incipient wetness and formed either by calcination or high-temperature H2 treatment. Structural features of the photocatalysts were established by X-ray powder diffraction (XRD), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS), optical absorption, Raman spectroscopy and TEM measurements. In situ reduction of Pt during the photocatalytic reaction was generally observed. The P25-based samples showed the best H2 production, while the activity of all sol-gel-based samples was similar in spite of the varying microstructures resulting from the different preparation conditions. Accordingly, the sol-gel-based TiO2 has a fundamental structural feature interfering with its photocatalytic performance, which could not be improved by annealing in the 400-500 °C range even by scarifying specific surface area at higher temperatures.
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Affiliation(s)
- Katalin Majrik
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
| | - Zoltán Pászti
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
| | - László Korecz
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
| | - Judith Mihály
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
| | - Zoltán May
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
| | - Péter Németh
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
- Department of Earth and Environmental Sciences, University of Pannonia, H-8200 Veszprém, Egyetem út 10, Hungary
| | - Catia Cannilla
- National Council of Research–CNR-ITAE, ‘‘Nicola Giordano’’, Via S. Lucia 5, 98126 Messina, Italy; (C.C.); (G.B.); (F.F.)
| | - Giuseppe Bonura
- National Council of Research–CNR-ITAE, ‘‘Nicola Giordano’’, Via S. Lucia 5, 98126 Messina, Italy; (C.C.); (G.B.); (F.F.)
| | - Francesco Frusteri
- National Council of Research–CNR-ITAE, ‘‘Nicola Giordano’’, Via S. Lucia 5, 98126 Messina, Italy; (C.C.); (G.B.); (F.F.)
| | - András Tompos
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
| | - Emília Tálas
- Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Eötvös Loránd Research Network (ELKH), H-1117 Budapest, Magyar Tudósok Körútja 2, Hungary; (K.M.); (L.K.); (J.M.); (Z.M.); (P.N.); (A.T.); (E.T.)
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Recent Developments of TiO 2-Based Photocatalysis in the Hydrogen Evolution and Photodegradation: A Review. NANOMATERIALS 2020; 10:nano10091790. [PMID: 32916899 PMCID: PMC7558756 DOI: 10.3390/nano10091790] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 01/01/2023]
Abstract
The growth of industrialization, which is forced to use non-renewable energy sources, leads to an increase in environmental pollution. Therefore, it is necessary not only to reduce the use of fossil fuels to meet energy needs but also to replace it with cleaner fuels. Production of hydrogen by splitting water is considered one of the most promising ways to use solar energy. TiO2 is an amphoteric oxide that occurs naturally in several modifications. This review summarizes recent advances of doped TiO2-based photocatalysts used in hydrogen production and the degradation of organic pollutants in water. An intense scientific and practical interest in these processes is aroused by the fact that they aim to solve global problems of energy conservation and ecology.
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Abstract
Hydrogen is considered to be an ideal energy carrier to achieve low-carbon economy and sustainable energy supply. Production of hydrogen by catalytic reforming of organic compounds is one of the most important commercial processes. With the rapid development of photocatalysis in recent years, the applications of photocatalysis have been extended to the area of reforming hydrogen evolution. This research area has attracted extensive attention and exhibited potential for wide application in practice. Photocatalytic reforming for hydrogen evolution is a sustainable process to convert the solar energy stored in hydrogen into chemical energy. This review comprehensively summarized the reported works in relevant areas, categorized by the reforming precursor (organic compound) such as methanol, ethanol and biomass. Mechanisms and characteristics for each category were deeply discussed. In addition, recommendations for future work were suggested.
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Walenta CA, Courtois C, Kollmannsberger SL, Eder M, Tschurl M, Heiz U. Surface Species in Photocatalytic Methanol Reforming on Pt/TiO2(110): Learning from Surface Science Experiments for Catalytically Relevant Conditions. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00260] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Constantin A. Walenta
- Chair of Physical Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, Garching 85748, Germany
| | - Carla Courtois
- Chair of Physical Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, Garching 85748, Germany
| | - Sebastian L. Kollmannsberger
- Chair of Physical Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, Garching 85748, Germany
| | - Moritz Eder
- Chair of Physical Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, Garching 85748, Germany
| | - Martin Tschurl
- Chair of Physical Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, Garching 85748, Germany
| | - Ueli Heiz
- Chair of Physical Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, Garching 85748, Germany
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