Cation‐Tuning Induced d‐Band Center Modulation on Co‐Based Spinel Oxide for Oxygen Reduction/Evolution Reaction

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(16)

Published: Dec. 31, 2021

Atomic substitutions at the tetrahedral site (ATd ) could theoretically achieve an efficient optimization of charge octahedral (BOh through ATd -O-BOh interactions in spinel oxides (AB2 O4 ). Despite substantial progress having been made, precise control and adjustment are still challenging owing to complexity their crystal structure. In this work, we demonstrate a simple solvent method tailor structures use oxide composites (ACo2 /NCNTs, A=Mn, Co, Ni, Cu, Zn) for oxygen electrocatalysis. The optimized MnCo2 /NCNTs exhibit high activity excellent durability reduction/evolution reactions. Remarkably, rechargeable liquid Zn-air battery equipped with cathode affords specific capacity 827 mAh gZn-1 power density 74.63 mW cm-2 no voltage degradation after 300 cycles charging-discharging rate (5 mA functional theory (DFT) calculations reveal that substitution regulate ratio Co3+ /Co2+ thereby lead modulation electronic structure accompanied movement d-band center. sites interact Mn-O-Co, Co3+Oh optimal allows more suitable binding interaction between active center oxygenated species, resulting superior electrocatalytic performance.

Language: Английский

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Anion-exchange membrane water electrolyzers and fuel cells

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(23), P. 9620 - 9693

Published: Jan. 1, 2022

The key components, working management, and operating techniques of anion-exchange membrane water electrolyzers fuel cells are reviewed for the first time.

Language: Английский

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Rapid complete reconfiguration induced actual active species for industrial hydrogen evolution reaction

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

Published: Oct. 2, 2022

Rational regulation of electrochemical reconfiguration and exploration activity origin are important foundations for realizing the optimization electrocatalyst activity, but rather challenging. Herein, we potentially develop a rapid complete strategy heterostructures CoC2O4 coated by MXene nanosheets (CoC2O4@MXene) during hydrogen evolution reaction (HER) process. The self-assembled CoC2O4@MXene nanotubular structure has high electronic accessibility abundant electrolyte diffusion channels, which favor reconfiguration. Such creates new actual catalytic active species Co(OH)2 transformed from CoC2O4, is coupled with to facilitate charge transfer decrease free energy Volmer step toward fast HER kinetics. reconfigured components require low overpotentials 28 216 mV at 10 1000 mA cm-2 in alkaline conditions decent stability natural seawater. This work gives insights understanding formation opens up way high-performance electrocatalysts.

Language: Английский

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Unraveling the Mechanism on Ultrahigh Efficiency Photocatalytic H₂O₂ Generation for Dual‐Heteroatom Incorporated Polymeric Carbon Nitride

Advanced Functional Materials, Journal Year: 2022, Volume and Issue: 32(38)

Published: July 13, 2022

Abstract Photocatalytic hydrogen peroxide (H 2 O ) production from dioxygen and water is regarded as a promising technology since it can achieve sustainable green solar‐to‐chemical energy conversion. Herein, oxygen potassium dual‐heteroatom incorporated polymeric carbon nitride (O/KCN) rationally designed for H generation with an ultrahigh rate of 309.44 µM h −1 mg , which surpasses that other C 3 N 4 ‐based photocatalysts. The enhanced performance be ascribed to the effective light absorption, fast charge transfer/separation, strong adsorption, highly selective two‐electron reduction reaction (ORR). Density functional theory calculations further confirm obtained O/KCN more favorable than others electrons migrating β spin‐orbital π* orbitals molecule, thus optimizing molecule activation promote formation intermediate species *OOH decrease barrier production. This work not only provides in‐depth insights photocatalytic mechanism, but also lays foundation development active photocatalysts environmental remediation

Language: Английский

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Optimizing the Oxygen‐Catalytic Performance of Zn–Mn–Co Spinel by Regulating the Bond Competition at Octahedral Sites

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(16)

Published: Jan. 22, 2023

Abstract By using the more electro‐negative Mn 3+ ion to partially replace Co at octahedral site of spinel ZnCo 2 O 4 , i.e., forming ternary Zn–Mn–Co oxide, electrocatalytic oxygen reduction/evolution activity is found be significantly increased. Considering physical characterization and theoretical calculations, it demonstrated that bond competition played a key role in regulating cobalt valence state activity. The partial replacement octahedral‐site‐occupied by can effectively modulate adjacent Co–O induce Jahn–Teller effect, thus changing originally stable crystal structure optimizing binding strength between active center reaction intermediates. Certainly, Mn‐substituted ZnMn 1.4 0.6 /NCNTs exhibit higher reduction (ORR) than /NCNTs, supporting covalency determines ORR . This study offers Mn–O bonds via B Oh –O–B edge‐sharing geometry. substitution sites less electronegative cations new effective way improve performance cobalt‐based oxides.

Language: Английский

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Successful preparation of BaCo _0.5Fe _0.5O _{3– δ} cathode oxide by rapidly cooling allowing for high-performance proton-conducting solid oxide fuel cells

Journal of Advanced Ceramics, Journal Year: 2023, Volume and Issue: 12(3), P. 587 - 597

Published: Feb. 17, 2023

A pure phase BaCo_0.5Fe_0.5O_3–δ (BCF), which cannot be obtained before, is successfully prepared in this study by using the calcination method with a rapid cooling procedure. The successful preparation of BCF allows evaluation material as cathode for proton-conducting solid oxide fuel cells (H-SOFCs) first time. An H-SOFC achieves an encouraging cell performance 2012 mW·cm^–2 at 700 ℃, two-fold higher than that similar classical high-performance Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3–δ (BSCF) cathode. First-principles calculations reveal mechanism enhancement, indicating new significantly lowers energy barriers oxygen reduction reaction (ORR) compared BSCF Therefore, improved and output are cell. also shows excellent long-term stability can work stably nearly 900 h without noticeable degradations. current superior to most H-SOFCs reported previous reports, suggesting promising H-SOFCs.

Language: Английский

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Hetero‐Anionic Structure Activated CoS Bonds Promote Oxygen Electrocatalytic Activity for High‐Efficiency Zinc–Air Batteries

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(36)

Published: May 18, 2023

Abstract The electronic structure of transition metal complexes can be modulated by replacing partial ion to obtain tuned intrinsic oxygen reduction reaction (ORR) or evolution (OER) electrocatalytic activity. However, the anion‐modulated ORR activity is still unsatisfactory, and construction hetero‐anionic remains challenging. Herein, an atomic doping strategy presented prepare CuCo 2 O 4‐x S x /NC‐2 (CCSO/NC‐2) as electrocatalysts, structrual characterization results favorably demonstrate substitution atoms for in CCSO/NC‐2, which shows excellent catalytic performance durability OER 0.1 m KOH. In addition, catalyst assembled Zinc–air battery with open circuit potential 1.43 V maintains after 300 h cyclic stability. Theoretical calculations differential charges illustrate that optimizes kinetics promotes electron redistribution. superior CCSO/NC‐2 catalysis mainly due its unique modulation main body. introduction CoO covalency constructs a fast transport channel, thus optimizing adsorption degree active site Co intermediates.

Language: Английский

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Surface Energy Mediated Sulfur Vacancy of ZnIn₂S₄ Atomic Layers for Photocatalytic H₂O₂ Production

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(35)

Published: May 14, 2023

Abstract Constructing rich defect active site structure for material design is still a great challenge. Herein, simple surface engineering strategy demonstrated to construct one‐unit‐cell ZnIn 2 S 4 atomic layers with the modulated energy of vacancy. Rich can regulate and control vacancy, which ensures sites, higher charge density effective carrier transport. As result, affords an obvious enhancement in H O productive rate 1592.04 µmol g −1 h , roughly 14.58 times superior that poor energy. Moreover, situ infrared diffuse reflection spectrum indicates vacancy as oxygen reduction reaction responsible critical intermediate *O − *OOH, corresponding two‐electron reaction. This study provides valuable insight guidance constructing controllably defects achieve highly efficient production.

Language: Английский

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Axial Oxygen Ligands Regulating Electronic and Geometric Structure of Zn‐N‐C Sites to Boost Oxygen Reduction Reaction

Advanced Science, Journal Year: 2023, Volume and Issue: 10(24)

Published: June 26, 2023

Zn-N-C possesses the intrinsic inertia for Fenton-like reaction and can retain robust durability in harsh circumstance, but it is often neglected oxygen reduction (ORR) because of its poor catalytic activity. Zn fully filled 3d

Language: Английский

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Regulating Reversible Oxygen Electrocatalysis by Built‐in Electric Field of Heterojunction Electrocatalyst with Modified d‐Band

Small, Journal Year: 2023, Volume and Issue: 19(15)

Published: Jan. 5, 2023

Developing bifunctional catalysts for oxygen electrochemical reactions is essential high-performance energy devices. Here, a Mott-Schottky heterojunction composed of porous cobalt-nitrogen-carbon (Co-N-C) polyhedra containing abundant metal-phosphides reversible electrocatalysis reported. As demonstration, this catalyst shows excellent activity in the and thus delivers outstanding performance rechargeable zinc-air batteries (ZABs). The built-in electric field can promote electron transfer electrocatalysis. More importantly, an appropriate d-band center also endows intermediates with balanced adsorption/desorption capability, enhancing consequently improving ZABs. work demonstrates important design principle preparing efficient multifunctional conversion technologies.

Language: Английский

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