Carbon Nitride Photocatalysts with Integrated Oxidation and Reduction Atomic Active Centers for Improved CO₂Conversion

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(34)

Опубликована: Июнь 18, 2022

Single-atom active-site catalysts have attracted significant attention in the field of photocatalytic CO2 conversion. However, designing active sites for reduction and H2 O oxidation simultaneously on a photocatalyst combining corresponding half-reaction system is still difficult. Here, we synthesized bimetallic single-atom with two compatible centers Mn Co carbon nitride (Mn1 Co1 /CN). Our experimental results density functional theory calculations showed that center promotes by accumulating photogenerated holes. In addition, activation increasing bond length angle molecules. Benefiting from synergistic effect atomic centers, Mn1 /CN exhibited CO production rate 47 μmol g-1 h-1 , which significantly higher than single-metal photocatalyst.

Язык: Английский

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Proximity Electronic Effect of Ni/Co Diatomic Sites for Synergistic Promotion of Electrocatalytic Oxygen Reduction and Hydrogen Evolution

Advanced Functional Materials, Год журнала: 2022, Номер 33(4)

Опубликована: Ноя. 13, 2022

Abstract The modulation effect manifests an encouraging potential to enhance the performance of single‐atom catalysts; however, in‐depth study about this for isolated diatomic sites (DASs) remains a great challenge. Herein, proximity electronic (PEE) Ni/Co DASs is proposed that anchored in N‐doped carbon (N‐C) substrate (NiCo DASs/N‐C) synergistic promoting electrocatalytic oxygen reduction reaction (ORR) and hydrogen evolution (HER). Benefiting from PEE adjacent Ni by four nitrogen (Ni‐N 4 ) moiety, NiCo DASs/N‐C catalyst exhibits superior ORR HER activity. In situ characterization results suggest Co (Co‐N as main active site O 2 adsorption‐activation process, which promotes formation key *OOH desorption *OH intermediate accelerate multielectron kinetics. Theoretical calculation reveals Ni‐N modulator can effectively adjust localization Co‐N site, *H adsorption on thereby boosting process significantly. This opens new opportunity rationally regulating catalytic centers well provides guidance designing high‐efficiency bifunctional electrocatalysts promising applications.

Язык: Английский

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Liquid Fluxional Ga Single Atom Catalysts for Efficient Electrochemical CO₂Reduction

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(3)

Опубликована: Ноя. 18, 2022

Precise design and tuning of the micro-atomic structure single atom catalysts (SACs) can help efficiently adapt complex catalytic systems. Herein, we inventively found that when active center main group element gallium (Ga) is downsized to atomic level, whose characteristic has significant differences from conventional bulk rigid Ga catalysts. The SACs with a P, S coordination environment display specific flow properties, showing CO products FE ≈92 % at -0.3 V vs. RHE in electrochemical CO2 reduction (CO2 RR). Theoretical simulations demonstrate adaptive dynamic transition optimizes adsorption energy *COOH intermediate renews sites time, leading excellent RR selectivity stability. This liquid system interfaces lays foundation for future exploration synthesis catalysis.

Язык: Английский

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Construction of Co₄ Atomic Clusters to Enable Fe−N₄ Motifs with Highly Active and Durable Oxygen Reduction Performance

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(30)

Опубликована: Май 24, 2023

Abstract Fe−N−C catalysts with single‐atom Fe−N 4 configurations are highly needed owing to the high activity for oxygen reduction reaction (ORR). However, limited intrinsic and dissatisfactory durability have significantly restrained practical application of proton‐exchange membrane fuel cells (PEMFCs). Here, we demonstrate that constructing adjacent metal atomic clusters (ACs) is effective in boosting ORR performance stability catalysts. The integration uniform Co ACs on N‐doped carbon substrate (Co @/Fe 1 @NC) realized through a “pre‐constrained” strategy using molecular Fe(acac) 3 implanted precursors. as‐developed @NC catalyst exhibits excellent half‐wave potential ( E 1/2 ) 0.835 V vs. RHE acidic media peak power density 840 mW cm −2 H 2 −O cell test. First‐principles calculations further clarify catalytic mechanism identified modified ACs. This work provides viable precisely establishing atomically dispersed polymetallic centers efficient energy‐related catalysis.

Язык: Английский

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Continuous Modulation of Electrocatalytic Oxygen Reduction Activities of Single‐Atom Catalysts throughp‐nJunction Rectification

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(5)

Опубликована: Ноя. 16, 2022

Fine-tuning single-atom catalysts (SACs) to surpass their activity limit remains challenging at atomic scale. Herein, we exploit p-type semiconducting character of SACs having a metal center coordinated nitrogen donors (MeNx ) and rectify local charge density by an n-type semiconductor support. With iron phthalocyanine (FePc) as model SAC, introducing gallium monosulfide that features low work function generates space-charged region across the junction interface, causes distortion FeN4 moiety spin-state transition in FeII center. This catalyst shows over two-fold higher specific oxygen-reduction than pristine FePc. We further employ three other chalcogenides varying supports, discover linear correlation between activities supported rectification degrees, which clearly indicates can be continuously tuned this strategy.

Язык: Английский

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Single-Atom Yttrium Engineering Janus Electrode for Rechargeable Na–S Batteries

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(41), С. 18995 - 19007

Опубликована: Окт. 10, 2022

The development of rechargeable Na-S batteries is very promising, thanks to their considerably high energy density, abundance elements, and low costs yet faces the issues sluggish redox kinetics S species polysulfide shuttle effect as well Na dendrite growth. Following theory-guided prediction, rare-earth metal yttrium (Y)-N4 unit has been screened a favorable Janus site for chemical affinity polysulfides electrocatalytic conversion, reversible uniform deposition. To this end, we adopt metal-organic framework (MOF) prepare single-atom hybrid with Y single atoms being incorporated into nitrogen-doped rhombododecahedron carbon host (Y SAs/NC), which features properties sodiophilicity sulfiphilicity thus presents highly desired electrochemical performance when used sodium anode sulfur cathode full cell. Impressively, cell capable delivering capacity 822 mAh g-1 shows superdurable cyclability (97.5% retention over 1000 cycles at current density 5 A g-1). proof-of-concept three-dimensional (3D) printed pouch validate potential practical applications such batteries, shedding light on promising cells future application in storage or power batteries.

Язык: Английский

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Phosphorus Tailors thed‐Band Center of Copper Atomic Sites for Efficient CO₂Photoreduction under Visible‐Light Irradiation

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(38)

Опубликована: Июль 8, 2022

Photoreduction of CO2 into solar fuels has received great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, two single-Cu-atom catalysts with unique Cu configurations in phosphorus-doped carbon nitride (PCN), namely, Cu1 N3 @PCN P3 were fabricated via selective phosphidation, tested visible light-driven reduction by H2 O without sacrificial agents. was exclusively active for CO production a rate 49.8 μmolCO gcat-1 h-1 , outperforming most polymeric (C3 N4 ) based catalysts, while preferably yielded . Experimental theoretical analysis suggested that doping P C3 replacing corner C atom upshifted the d-band center close to Fermi level, which boosted adsorption activation on making efficiently convert CO. In contrast, much lower 3d electron energy exhibited negligible adsorption, thereby preferring formation photocatalytic splitting.

Язык: Английский

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Recent advances of single-atom catalysts in CO₂conversion

Energy & Environmental Science, Год журнала: 2023, Номер 16(7), С. 2759 - 2803

Опубликована: Янв. 1, 2023

The catalytic transformation of CO 2 into valuable fuels/chemicals is a promising and economically profitable process because it offers an alternative toward fossil feedstocks the benefit transforming cycling on scale-up.

Язык: Английский

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Review of Carbon Support Coordination Environments for Single Metal Atom Electrocatalysts (SACS)

Advanced Materials, Год журнала: 2023, Номер 36(1)

Опубликована: Апрель 20, 2023

This topical review focuses on the distinct role of carbon support coordination environment single-atom catalysts (SACs) for electrocatalysis. The article begins with an overview atomic configurations in SACs, including a discussion advanced characterization techniques and simulation used understanding active sites. A summary key electrocatalysis applications is then provided. These processes are oxygen reduction reaction (ORR), evolution (OER), hydrogen (HER), nitrogen (NRR), dioxide (CO

Язык: Английский

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Tuning Mass Transport in Electrocatalysis Down to Sub‐5 nm through Nanoscale Grade Separation

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(3)

Опубликована: Ноя. 18, 2022

Nano and single-atom catalysis open new possibilities of producing green hydrogen (H2 ) by water electrolysis. However, for the evolution reaction (HER) which occurs at a characteristic rate proportional to potential, fast generation H2 nanobubbles atomic-scale interfaces often leads blockage active sites. Herein, nanoscale grade-separation strategy is proposed tackle mass-transport problem utilizing ordered three-dimensional (3d) interconnected sub-5 nm pores. The results reveal that 3d criss-crossing mesopores with grade separation allow efficient diffusion bubbles along channels. After support ultrafine ruthenium (Ru), are on superior level two-dimensional system maximizing catalyst performance obtained Ru outperforms most other HER catalysts. This work provides potential route fine-tuning few-nanometer mass transport during

Язык: Английский

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