Engineering Dual Single‐Atom Sites on 2D Ultrathin N‐doped Carbon Nanosheets Attaining Ultra‐Low‐Temperature Zinc‐Air Battery

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(12)

Опубликована: Янв. 7, 2022

Herein, a novel dual single-atom catalyst comprising adjacent Fe-N4 and Mn-N4 sites on 2D ultrathin N-doped carbon nanosheets with porous structure (FeMn-DSAC) was constructed as the cathode for flexible low-temperature Zn-air battery (ZAB). FeMn-DSAC exhibits remarkable bifunctional activities oxygen reduction reaction (ORR) evolution (OER). Control experiments density functional theory calculations reveal that catalytic activity arises from cooperative effect of Fe/Mn dual-sites aiding *OOH dissociation well nanosheet promoting active sits exposure mass transfer during process. The excellent enables ZAB to operate efficiently at ultra-low temperature -40 °C, delivering 30 mW cm-2 peak power retaining up 86 % specific capacity room counterpart.

Язык: Английский

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Identification of the Highly Active Co–N₄ Coordination Motif for Selective Oxygen Reduction to Hydrogen Peroxide

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(32), С. 14505 - 14516

Опубликована: Авг. 3, 2022

Electrosynthesis of hydrogen peroxide (H

Язык: Английский

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Oxygen Evolution/Reduction Reaction Catalysts: From In Situ Monitoring and Reaction Mechanisms to Rational Design

Chemical Reviews, Год журнала: 2023, Номер 123(9), С. 6257 - 6358

Опубликована: Март 21, 2023

The oxygen evolution reaction (OER) and reduction (ORR) are core steps of various energy conversion storage systems. However, their sluggish kinetics, i.e., the demanding multielectron transfer processes, still render OER/ORR catalysts less efficient for practical applications. Moreover, complexity catalyst–electrolyte interface makes a comprehensive understanding intrinsic mechanisms challenging. Fortunately, recent advances in situ/operando characterization techniques have facilitated kinetic monitoring under conditions. Here we provide selected highlights mechanistic studies with main emphasis placed on heterogeneous systems (primarily discussing first-row transition metals which operate basic conditions), followed by brief outlook molecular catalysts. Key sections this review focused determination true active species, identification sites, reactive intermediates. For in-depth insights into above factors, short overview metrics accurate characterizations is provided. A combination obtained time-resolved information reliable activity data will then guide rational design new Strategies such as optimizing restructuring process well overcoming adsorption-energy scaling relations be discussed. Finally, pending current challenges prospects toward development homogeneous presented.

Язык: Английский

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High Durability of Fe–N–C Single‐Atom Catalysts with Carbon Vacancies toward the Oxygen Reduction Reaction in Alkaline Media

Advanced Materials, Год журнала: 2023, Номер 35(14)

Опубликована: Янв. 11, 2023

Single-atom catalysts (SACs) have attracted extensive interest to catalyze the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries. However, development of SACs with high selectivity long-term stability is a great challenge. In this work, carbon vacancy modified Fe-N-C (FeH -N-C) are practically designed synthesized through microenvironment modulation, achieving high-efficient utilization active sites optimization electronic structures. The FeH -N-C catalyst exhibits half-wave potential (E1/2 ) 0.91 V sufficient durability 100 000 voltage cycles 29 mV E1/2 loss. Density functional theory (DFT) calculations confirm that vacancies around metal-N4 can reduce adsorption free energy OH*, hinder dissolution metal center, significantly enhancing ORR kinetics stability. Accordingly, presented high-power density over 1200 h rechargeable zinc-air batteries (ZABs). This work will not only guide for developing highly stable rational modulation sites, but also provide an insight into structure boost electrocatalytical performances.

Язык: Английский

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Boosting Oxygen Electrocatalytic Activity of Fe–N–C Catalysts by Phosphorus Incorporation

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(6), С. 3647 - 3655

Опубликована: Фев. 6, 2023

Nitrogen-doped graphitic carbon materials hosting single-atom iron (Fe-N-C) are major non-precious metal catalysts for the oxygen reduction reaction (ORR). The nitrogen-coordinated Fe sites described as first coordination sphere. As opposed to good performance in ORR, that evolution (OER) is extremely poor due sluggish O-O coupling process, thus hampering practical applications of rechargeable zinc (Zn)-air batteries. Herein, we succeed boosting OER activity Fe-N-C by additionally incorporating phosphorus atoms into second sphere, here denoted P/Fe-N-C. resulting material exhibits excellent 0.1 M KOH with an overpotential low 304 mV at a current density 10 mA cm-2. Even more importantly, they exhibit remarkably small ORR/OER potential gap 0.63 V. Theoretical calculations using first-principles functional theory suggest enhances electrocatalytic balancing *OOH/*O adsorption FeN4 sites. When used air cathode Zn-air battery, P/Fe-N-C delivers charge-discharge high peak power 269 mW cm-2, highlighting its role state-of-the-art bifunctional electrocatalyst.

Язык: Английский

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Carbon‐Based Electrocatalysts for Efficient Hydrogen Peroxide Production

Advanced Materials, Год журнала: 2021, Номер 33(49)

Опубликована: Сен. 24, 2021

Abstract Hydrogen peroxide (H 2 O ) is an environment‐friendly and efficient oxidant with a wide range of applications in different industries. Recently, the production hydrogen through direct electrosynthesis has attracted widespread research attention, emerged as most promising method to replace traditional energy‐intensive multi‐step anthraquinone process. In ongoing efforts achieve highly large‐scale H , carbon‐based materials have been developed 2e − oxygen reduction reaction catalysts, benefits low cost, abundant availability, optimal performance. This review comprehensively introduces strategies for optimizing toward production, latest advances hybrid catalysts. The active sites influence coordination heteroatom doping on selectivity are extensively analyzed. particular, appropriate design functional groups understanding effect electrolyte pH expected further improve selective efficiency producing via reaction. Methods improving catalytic activity by interface engineering kinetics summarized. Finally, challenges catalysts face before they can be employed commercial‐scale identified, prospects designing novel electrochemical reactors proposed.

Язык: Английский

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Cation‐Vacancy‐Enriched Nickel Phosphide for Efficient Electrosynthesis of Hydrogen Peroxides

Advanced Materials, Год журнала: 2022, Номер 34(16)

Опубликована: Фев. 22, 2022

Electrocatalytic hydrogen peroxide (H2 O2 ) synthesis via the two-electron oxygen reduction reaction (2e ORR) pathway is becoming increasingly important due to green production process. Here, cationic vacancies on nickel phosphide, as a proof-of-concept regulate catalyst's physicochemical properties, are introduced for efficient H2 electrosynthesis. The as-fabricated Ni (VNi )-enriched Ni2-x P-VNi electrocatalyst exhibits remarkable 2e ORR performance with molar fraction of >95% and Faradaic efficiencies >90% in all pH conditions under wide range applied potentials. Impressively, as-created VNi possesses superb long-term durability over 50 h, suppassing recently reported catalysts Operando X-ray absorption near-edge spectroscopy (XANES) synchrotron Fourier transform infrared (SR-FTIR) combining theoretical calculations reveal that excellent catalytic originates from -induced geometric electronic structural optimization, thus promoting adsorption favored "end-on" configuration. It believed demonstrated cation vacancy engineering an effective strategy toward creating active heterogeneous atomic precision.

Язык: 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, Год журнала: 2022, Номер 61(29)

Опубликована: Май 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.

Язык: Английский

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Ru–Co Pair Sites Catalyst Boosts the Energetics for the Oxygen Evolution Reaction

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(32)

Опубликована: Май 31, 2022

Abstract Manipulating the coordination environment of active center via anion modulation to reveal tailored activity and selectivity has been widely achieved, especially for carbon‐based single‐atom site catalysts (SACs). However, tuning ligand fields by single‐site metal cation regulation identifying effects on resulting electronic configuration is seldom explored. Herein, we propose a Ru strategy engineer properties constructing Ru/LiCoO 2 SAC with atomically dispersed Ru−Co pair sites. Benefitting from strong coupling between Co sites, catalyst possesses an enhanced electrical conductivity achieves near‐optimal oxygen adsorption energies. Therefore, optimized delivers superior evolution reaction (OER) low overpotential, high mass 1000 A g oxide −1 at small overpotential 335 mV, excellent long‐term stability. It also exhibits rapid kinetics rate capability outstanding durability in zinc–air battery.

Язык: Английский

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Engineering the Local Atomic Environments of Indium Single‐Atom Catalysts for Efficient Electrochemical Production of Hydrogen Peroxide

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(12)

Опубликована: Янв. 19, 2022

The in-depth understanding of local atomic environment-property relationships p-block metal single-atom catalysts toward the 2 e- oxygen reduction reaction (ORR) has rarely been reported. Here, guided by first-principles calculations, we develop a heteroatom-modified In-based metal-organic framework-assisted approach to accurately synthesize an optimal catalyst, in which single In atoms are anchored combined N,S-dual first coordination and B second supported hollow carbon rods (In SAs/NSBC). SAs/NSBC catalyst exhibits high H2 O2 selectivity above 95 % wide range pH. Furthermore, SAs/NSBC-modified natural air diffusion electrode unprecedented production rate 6.49 mol peroxide gcatalyst-1 h-1 0.1 M KOH electrolyte 6.71 PBS electrolyte. This strategy enables design next-generation high-performance materials, provides practical guidance for electrosynthesis.

Язык: Английский

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