Sustainable organic synthesis promoted on titanium dioxide using coordinated water and renewable energies/resources

Yamauchi, Miho; Saito, Hikaru; Sugimoto, Toshiki; Mori, Shogo; Saitō, Susumu

doi:10.1016/j.ccr.2022.214773

Cited by 23 publications

(19 citation statements)

References 205 publications

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“…Finally, we remark that our new concept of the metal cocatalyst also rationalizes well the previously reported incomprehensible results in the photocatalytic oxidation of organic molecules [48][49][50][51] .…”

Section: Manifestation Of Hole Accumulationsupporting

confidence: 89%

Beyond reduction cocatalysts: critical role of metal cocatalysts in photocatalytic oxidation of methane with water

Saito

Sato

Higashi

et al. 2023

Preprint

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Environmentally sustainable and selective conversion of methane to valuable chemicals under ambient conditions is pivotal for the development of next-generation photocatalytic technology. However, due to the lack of microscopic knowledge about non-thermal methane conversion, controlling and modulating photocatalytic oxidation processes driven by photogenerated holes remain a challenge. Here, we report novel function of metal cocatalysts to accept photogenerated holes and dominate the oxidation selectivity of methane, which is clearly beyond the conventional concept in photocatalysis that the metal cocatalysts loaded on the surfaces of semiconductor photocatalysts mostly capture photogenerated electrons and dominate reduction reactions exclusively. The novel photocatalytic role of metal cocatalysts was verified by operando molecular spectroscopy combined with real-time mass spectrometry for metal-loaded Ga2O3 model photocatalysts under methane gas and water vapor at ambient temperature and pressure. Our concept of metal cocatalysts that work as active sites for both photocatalytic oxidation and reduction provides a new understanding of photocatalysis and a solid basis for controlling the non-thermal redox reactions by metal-cocatalyst engineering.

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Section: Manifestation Of Hole Accumulationsupporting

confidence: 89%

Beyond reduction cocatalysts: critical role of metal cocatalysts in photocatalytic oxidation of methane with water

Saito

Sato

Higashi

et al. 2023

Preprint

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“…Photocatalysis is a promising technology in which redox reactions are promoted by light; endergonic reactions such as water splitting [6][7][8] , CO 2 reduction 9 , and organic synthesis with water 10 can be photocatalyzed at ambient conditions beyond thermodynamic limitations 11 . Recently, the application of photocatalytic technology to the conversion of methane with robust C-H bonds has been reported 12,13 .…”

mentioning

confidence: 99%

“…In principle, the oxidation and reduction reactions are induced on the surface of photocatalysts by photogenerated holes and electrons, respectively. However, despite intensive research in the past, the microscopic mechanism of non-thermal methane activation is not yet clear [6][7][8][9][10][11][12][13] .…”

mentioning

confidence: 99%

Critical impacts of interfacial water on C–H activation in photocatalytic methane conversion

et al. 2023

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On-site and on-demand photocatalytic methane conversion under ambient conditions is one of the urgent global challenges for the sustainable use of ubiquitous methane resources. However, the lack of microscopic knowledge on its reaction mechanism prevents the development of engineering strategies for methane photocatalysis. Combining real-time mass spectrometry and operando infrared absorption spectroscopy with ab initio molecular dynamics simulations, here we report key molecular-level insights into photocatalytic green utilization of methane. Activation of the robust C–H bond of methane is hardly induced by the direct interaction with photogenerated holes trapped at the surface of photocatalyst; instead, the C–H activation is significantly promoted by the photoactivated interfacial water species. The interfacial water hydrates and properly stabilizes hydrocarbon radical intermediates, thereby suppressing their overstabilization. Owing to these water-assisted effects, the photocatalytic conversion rates of methane under wet conditions are dramatically improved by typically more than 30 times at ambient temperatures (~300 K) and pressures (~1 atm) in comparison to those under dry conditions. This study sheds new light on the role of interfacial water and provides a firm basis for design strategies for non-thermal heterogeneous catalysis of methane under ambient conditions.

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“…67 68 Sugimoto and co-workers recently reported that methyl radicals would be stabilized on an SP surface, which would also be affected by H 2 O molecules adsorbed on the surface, based on their theoretical calculations. 69 Thus, the water content of the reaction mixture should be carefully optimized 37 for efficient and selective β-scission.…”

Section: Discussionmentioning

confidence: 99%

“…This study provided us the inspiration for our ongoing project 'artificial photosynthesis directing toward organic synthesis' using water as the key reagent. 37 While the success in Ru/SrTiO 3 :Rh-photocatalysis convinced us of the versatility of SPs in organic synthesis, the dehydrogenation protocol still had several drawbacks: (i) A simple 1° aliphatic alcohol 19l was transformed into the corresponding aldehyde in relatively low yield (20l, Figure 4C). This could partially be attributed to the over-oxidation of 20l to the carboxylic acid 21l.…”

Section: Account Synlettmentioning

confidence: 99%

Metal-Loaded Semiconductor-Photocatalysis of Alcohols for Selective Organic Synthesis: A Personal Account

Mori

Sakurai

Naka

et al. 2023

Synlett

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In this account, we review our research over the last decade on metal-loaded semiconductor-photocatalyzed organic transformations using alcohols. Different from many reactions using alcohols as mere sacrificial electron donors, our study has demonstrated alcohols as useful organic building blocks incorporated into value-added products. Besides such recollections of previous results, we briefly introduce our ongoing project involving photocatalytic C–C bond-forming reactions via the C–C bond scission of tertiary alcohols. 1 Introduction 2 Dehydroxylative hydrogenolysis of allylic alcohols 3 Acceptorless dehydrogenation of activated/unactivated alcohols 4 N-Alkylation of amines using alcohols as alkylating agents 5 Summary and outlook

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Sustainable organic synthesis promoted on titanium dioxide using coordinated water and renewable energies/resources

Cited by 23 publications

References 205 publications

Beyond reduction cocatalysts: critical role of metal cocatalysts in photocatalytic oxidation of methane with water

Beyond reduction cocatalysts: critical role of metal cocatalysts in photocatalytic oxidation of methane with water

Critical impacts of interfacial water on C–H activation in photocatalytic methane conversion

Metal-Loaded Semiconductor-Photocatalysis of Alcohols for Selective Organic Synthesis: A Personal Account

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