Operando Cooperated Catalytic Mechanism of Atomically Dispersed Cu−N₄ and Zn−N₄ for Promoting Oxygen Reduction Reaction

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(25), P. 14005 - 14012

Published: March 31, 2021

Abstract Dual‐metal single‐atom catalysts exhibit superior performance for oxygen reduction reaction (ORR), however, the synergistic catalytic mechanism is not deeply understood. Herein, we report a dual‐metal catalyst consisted of Cu−N 4 and Zn−N on N‐doped carbon support (Cu/Zn−NC). It exhibits high‐efficiency ORR activity with an E onset 0.98 V 1/2 0.83 V, excellent stability (no degradation after 10 000 cycles), surpassing state‐of‐the‐art Pt/C great mass Pt‐free single atom catalysts. Operando XANES demonstrates that as active center experiences change from atomic dispersion to cluster cooperation during process, then turns state again reaction. DFT calculation further indicates adjustment effect Zn d‐orbital electron distribution Cu could benefit stretch cleavage O‐O center, speeding up process rate determining step OOH*.

Language: Английский

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Single-atom catalysts for photocatalytic energy conversion

Joule, Journal Year: 2022, Volume and Issue: 6(1), P. 92 - 133

Published: Jan. 1, 2022

Artificial photocatalytic energy conversion represents a highly intriguing strategy for solving the crisis and environmental problems by directly harvesting solar energy. The development of efficient photocatalysts is central task pushing real-world application reactions. Due to maximum atomic utilization efficiency distinct advantages outstanding catalytic activity, single-atom catalysts (SACs) have emerged as promising candidates photocatalysts. In current review, recent progresses challenges on SACs systems are presented. Fundamental principles focusing charge separation/transfer molecular adsorption/activation photocatalysis systemically explored. We outline how isolated reactive sites facilitate photogenerated electron–hole transfer promote construction photoactivation cycles. widespread adoption in diverse reactions also comprehensively introduced. By presenting these advances addressing some future with potential solutions related integral over SACs, we expect shed light forthcoming research conversion.

Language: Английский

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Protruding Pt single-sites on hexagonal ZnIn2S4 to accelerate photocatalytic hydrogen evolution

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: March 11, 2022

Single-site cocatalysts engineered on supports offer a cost-efficient pathway to utilize precious metals, yet improving the performance further with minimal catalyst loading is still highly desirable. Here we have conducted photochemical reaction stabilize ultralow Pt co-catalysts (0.26 wt%) onto basal plane of hexagonal ZnIn2S4 nanosheets (PtSS-ZIS) form Pt-S3 protrusion tetrahedron coordination structure. Compared traditional defect-trapped single-site counterparts, protruding single-sites h-ZIS photocatalyst enhance H2 evolution yield rate by factor 2.2, which could reach 17.5 mmol g-1 h-1 under visible light irradiation. Importantly, through simple drop-casting, thin PtSS-ZIS film prepared, and large amount observable bubbles are generated, providing great potential for practical solar-light-driven production. The single atoms in inhibit recombination electron-hole pairs cause tip effect optimize adsorption/desorption behavior H effective proton mass transfer, synergistically promote thermodynamics kinetics.

Language: Английский

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Atomic‐Level Charge Separation Strategies in Semiconductor‐Based Photocatalysts

Advanced Materials, Journal Year: 2021, Volume and Issue: 33(10)

Published: Jan. 27, 2021

Abstract Semiconductor‐based photocatalysis as a productive technology furnishes prospective solution to environmental and renewable energy issues, but its efficiency greatly relies on the effective bulk surface separation of photoexcited charge carriers. Exploitation atomic‐level strategies allows in‐depth understanding related mechanisms enables bottom‐up precise design photocatalysts, significantly enhancing photocatalytic activity. Herein, advances toward developing robust photocatalysts are highlighted, elucidating fundamentals transfer processes advanced probing techniques. The strategies, embodied by regulation movement pathway migration dynamic, boil down shortening diffusion distance atomic‐scale, establishing channels, driving force. Meanwhile, regulating in‐plane structure spatial summarized strategies. Moreover, collaborative for simultaneous manipulation photocharges also introduced. Finally, existing challenges future prospects fabrication state‐of‐the‐art discussed basis thorough comprehension

Language: Английский

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Ultrathin Porous Carbon Nitride Bundles with an Adjustable Energy Band Structure toward Simultaneous Solar Photocatalytic Water Splitting and Selective Phenylcarbinol Oxidation

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(9), P. 4815 - 4822

Published: Nov. 3, 2020

Abstract Actiniae‐like carbon nitride (ACN) bundles were synthesized by the pyrolysis of an asymmetric supramolecular precursor prepared from L‐arginine (L‐Arg) and melamine. ACN has adjustable band gaps (2.25 eV–2.75 eV) hollow microtubes with ultrathin pore walls, which enrich reaction sites, improve visible‐light absorption enhance charge separation. In presence phenylcarbinol, exhibited excellent water‐splitting ability (95.3 μmol h −1 ) in meanwhile phenylcarbinol was selectively oxidized to benzaldehyde (conversion 90.9 %, selectivity 99.7 %) under solar irradiation. For concurrent reactions, 2 D isotope labeling, separation, detection conducted confirm that proton source released hydrogen is water. The mechanism water splitting oxidation also investigated.

Language: Английский

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2D g-C3N4 for advancement of photo-generated carrier dynamics: Status and challenges

Materials Today, Journal Year: 2020, Volume and Issue: 41, P. 270 - 303

Published: Oct. 31, 2020

Language: Английский

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Platinum Single Atoms Anchored on a Covalent Organic Framework: Boosting Active Sites for Photocatalytic Hydrogen Evolution

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(21), P. 13266 - 13279

Published: Oct. 18, 2021

It is of great importance to explore and achieve a more effective approach toward the controllable synthesis single-atom-based photocatalysts with high metal content long-term durability. Herein, single-atom platinum (Pt) loading anchored on pore walls two-dimensional β-ketoenamine-linked covalent organic frameworks (TpPa-1-COF) presented. Aided by advanced characterization techniques aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC HAADF-STEM) X-ray absorption fine structure (XAFS) spectroscopy, it has been demonstrated that atomically dispersed Pt formed TpPa-1-COF support through six-coordinated C3N–Pt–Cl2 species. The optimized Pt1@TpPa-1 catalyst exhibits photocatalytic H2 evolution rate 719 μmol g–1 h–1 under visible-light irradiation, actual 0.72 wt %, large turnover frequency (TOF) 19.5 h–1, activity equivalent 3.9 48 times higher than those nanoparticles/TpPa-1 bare TpPa-1, respectively. improved performance for ascribed photogenerated charge separation migration well-dispersed active sites Pt. Moreover, density functional theory (DFT) calculations further reveal role single atoms in enhanced evolution. Overall, this work provides some inspiration designing outstanding stability efficiency using COFs as support.

Language: Английский

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Cobalt Single Atoms Anchored on Oxygen‐Doped Tubular Carbon Nitride for Efficient Peroxymonosulfate Activation: Simultaneous Coordination Structure and Morphology Modulation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(29)

Published: May 6, 2022

Abstract Simultaneous regulation of the coordination environment single‐atom catalysts (SACs) and engineering architectures with efficient exposed active sites are strategies for boosting peroxymonosulfate (PMS) activation. We isolated cobalt atoms dual nitrogen oxygen (Co−N 3 O 1 ) on oxygen‐doped tubular carbon nitride (TCN) by pyrolyzing a hydrogen‐bonded cyanuric acid melamine–cobalt acetate precursor. The theoretically constructed Co−N moiety TCN exhibited an impressive mass activity 7.61×10 5 min −1 mol high 2 selectivity. Theoretical calculations revealed that single occupied environment, PMS adsorption was promoted energy barriers reduced key *O intermediate produced . were attached to widely used poly(vinylidene fluoride) microfiltration membrane deliver antibiotic wastewater treatment system 97.5 % ciprofloxacin rejection over 10 hours, thereby revealing suitability industrial applications.

Language: Английский

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Engineered Graphitic Carbon Nitride-Based Photocatalysts for Visible-Light-Driven Water Splitting: A Review

Energy & Fuels, Journal Year: 2021, Volume and Issue: 35(8), P. 6504 - 6526

Published: April 5, 2021

Graphitic carbon nitride (g-C3N4), a polymeric semiconductor, has become rising star for photocatalytic energy conversion because of its facile accessibility, metal-free nature, low cost, and environmentally benign properties. This work reviews the latest progress g-C3N4-based materials in visible-light-driven water splitting to hydrogen. It begins with brief history g-C3N4, followed by various engineering strategies such as elemental doping, copolymerization, crystalline tailoring, surface engineering, single-atom modification, elevated decomposition. In addition, synthesis g-C3N4 different dimensions (0D, 1D, 2D, 3D) configurations series heterojunctions (type II, Z-scheme, S-scheme, g-C3N4/metal, g-C3N4/carbon heterojunctions) were also discussed their improvement hydrogen production. Lastly, challenges opportunities nanomaterials are provided. is anticipated that this review will promote further development emerging more efficiency

Language: Английский

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Developing Ni single-atom sites in carbon nitride for efficient photocatalytic H2O2 production

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

Published: Nov. 6, 2023

Photocatalytic two-electron oxygen reduction to produce high-value hydrogen peroxide (H2O2) is gaining popularity as a promising avenue of research. However, structural evolution mechanisms catalytically active sites in the entire photosynthetic H2O2 system remains unclear and seriously hinders development highly-active stable photocatalysts. Herein, we report high-loading Ni single-atom photocatalyst for efficient synthesis pure water, achieving an apparent quantum yield 10.9% at 420 nm solar-to-chemical conversion efficiency 0.82%. Importantly, using situ synchrotron X-ray absorption spectroscopy Raman directly observe that initial Ni-N3 dynamically transform into high-valent O1-Ni-N2 after O2 adsorption further evolve form key *OOH intermediate before finally forming HOO-Ni-N2. Theoretical calculations experiments reveal structure reduces formation energy barrier suppresses O=O bond dissociation, leading improved production activity selectivity.

Language: Английский

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