An Atomically Dispersed Mn-Photocatalyst for Generating Hydrogen Peroxide from Seawater via the Water Oxidation Reaction (WOR)

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(30), P. 16584 - 16596

Published: July 24, 2023

In this work, we have fabricated an aryl amino-substituted graphitic carbon nitride (g-C3N4) catalyst with atomically dispersed Mn capable of generating hydrogen peroxide (H2O2) directly from seawater. This new exhibited excellent reactivity, obtaining up to 2230 μM H2O2 in 7 h alkaline water and 1800 seawater under identical conditions. More importantly, the was quickly recovered for subsequent reuse without appreciable loss performance. Interestingly, unlike usual two-electron oxygen reduction reaction pathway, generation through a less common oxidation (WOR) process which both direct indirect WOR processes occurred; namely, photoinduced h+ oxidized H2O via one-step 2e- WOR, first hydroxide (OH-) ion generate hydroxy radical (•OH), formed indirectly by combination two •OH. We characterized material, at catalytic sites, atomic level using electron paramagnetic resonance, X-ray absorption near edge structure, extended fine high-resolution transmission microscopy, photoelectron spectroscopy, magic-angle spinning solid-state NMR multiscale molecular modeling, combining classical reactive dynamics simulations quantum chemistry calculations.

Language: Английский

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Promoting Solar‐driven Hydrogen Peroxide Production over Thiazole‐based Conjugated Polymers via Generating and Converting Singlet Oxygen

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(40)

Published: Aug. 16, 2023

Solar-driven synthesis of hydrogen peroxide (H2 O2 ) from water and air provides a low-cost eco-friendly alternative route to the traditional anthraquinone method. Herein, four thiazole-based conjugated polymers (Tz-CPs: TTz, BTz, TBTz BBTz) are synthesized via aldimine condensation. BBTz exhibits highest H2 production rate 7274 μmol g-1 h-1 in pure water. Further, reaction path is analyzed by electron paramagnetic resonance (EPR), situ diffuse reflectance infrared Fourier transform (DRIFT) theoretical calculation, highlighting prominent role singlet oxygen (1 ). The generation 1 occurs through oxidation superoxide radical (⋅O2- subsequent conversion into endoperoxides [4+2] cycloaddition over BBTz, which promotes charge separation reduces barrier for production. This work new insight mechanism photocatalytic reduction molecular design superior single-polymer photocatalysts.

Language: Английский

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Regulating Relative Nitrogen Locations of Diazine Functionalized Covalent Organic Frameworks for Overall H₂O₂ Photosynthesis

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(41)

Published: Aug. 26, 2023

Nitrogen-heterocycle-based covalent organic frameworks (COFs) are considered promising candidates for the overall photosynthesis of hydrogen peroxide (H2 O2 ). However, effects relative nitrogen locations remain obscured and photocatalytic performances COFs need to be further improved. Herein, a collection functionalized by various diazines including pyridazine, pyrimidine, pyrazine have been judiciously designed synthesized photogeneration H2 without sacrificial agents. Compared with pyrimidine pyrazine, pyridazine embedded in TpDz tends stabilize endoperoxide intermediate species, leading toward more efficient direct 2e- oxygen reduction reaction (ORR) pathway. Benefiting from effective electron-hole separation, low charge transfer resistance, high-efficiency ORR pathway, an excellent production rate 7327 μmol g-1 h-1 solar-to-chemical conversion (SCC) value 0.62 % has achieved TpDz, which ranks one best COF-based photocatalysts. This work might shed fresh light on rational design functional targeting photocatalysts production.

Language: Английский

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Efficient photocatalytic production of hydrogen peroxide using dispersible and photoactive porous polymers

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Oct. 28, 2023

Developing efficient artificial photocatalysts for the biomimetic photocatalytic production of molecular materials, including medicines and clean energy carriers, remains a fundamentally technologically essential challenge. Hydrogen peroxide is widely used in chemical synthesis, medical disinfection, energy. However, current industrial production, predominantly by anthraquinone oxidation, suffers from hefty penalties toxic byproducts. Herein, we report hydrogen protonation-induced dispersible porous polymers with good charge-carrier transport properties. Significant generation occurs under ambient conditions at an unprecedented rate 23.7 mmol g-1 h-1 apparent quantum efficiency 11.3% 450 nm. Combined simulations spectroscopies indicate that sub-picosecond ultrafast electron "localization" both free carriers exciton states catalytic reaction centers underlie remarkable performance polymers.

Language: Английский

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Solar Light Driven H₂O₂ Production and Selective Oxidations Using a Covalent Organic Framework Photocatalyst Prepared by a Multicomponent Reaction

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(29)

Published: May 8, 2023

A chemically stable 2D microporous COF (PMCR-1) was synthesized via the multicomponent Povarov reaction. PMCR-1 exhibits a remarkable and long-term photocatalytic H2 O2 production rate (60 h) from pure sea water under visible light. The is markedly enhanced when benzyl alcohol (BA) added as reductant, which also due to strong π-π interaction of BA with dangling phenyl moieties in pores introduced by Motivated concomitant oxidation benzaldehyde during formation, various organic substrates such amine methyl sulfide derivatives investigated. It shown that well-defined micropores enable size-selective oxidation.

Language: Английский

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