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

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(9), P. 6257 - 6358

Published: March 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.

Language: Английский

---

Stabilizing Fe–N–C Catalysts as Model for Oxygen Reduction Reaction

Advanced Science, Journal Year: 2021, Volume and Issue: 8(23)

Published: Oct. 23, 2021

Abstract The highly efficient energy conversion of the polymer‐electrolyte‐membrane fuel cell (PEMFC) is extremely limited by sluggish oxygen reduction reaction (ORR) kinetics and poor electrochemical stability catalysts. Hitherto, to replace costly Pt‐based catalysts, non‐noble‐metal ORR catalysts are developed, among which transition metal–heteroatoms–carbon (TM–H–C) materials present great potential for industrial applications due their outstanding catalytic activity low expense. However, during testing in a two‐electrode system high complexity have become big barrier commercial applications. Thus, herein, simplify research, typical Fe–N–C material with relatively simple constitution structure, selected as model catalyst TM–H–C explore improve such kind Then, different types active sites (centers) coordination systematically summarized discussed, possible attenuation mechanism strategies analyzed. Finally, some challenges faced prospects proposed shed light on future development trend advanced catalysis.

Language: Английский

---

Tailoring of electrocatalyst interactions at interfacial level to benchmark the oxygen reduction reaction

Coordination Chemistry Reviews, Journal Year: 2022, Volume and Issue: 469, P. 214669 - 214669

Published: June 22, 2022

Language: Английский

---

Altering the spin state of Fe-N-C through ligand field modulation of single-atom sites boosts the oxygen reduction reaction

Nano Energy, Journal Year: 2022, Volume and Issue: 105, P. 108020 - 108020

Published: Nov. 21, 2022

Language: Английский

---

Recent progress of metal single-atom catalysts for energy applications

Nano Energy, Journal Year: 2023, Volume and Issue: 111, P. 108404 - 108404

Published: April 5, 2023

Language: Английский

---

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

---

Exploring Durable Single-Atom Catalysts for Proton Exchange Membrane Fuel Cells

ACS Energy Letters, Journal Year: 2022, Volume and Issue: 7(5), P. 1696 - 1705

Published: April 15, 2022

Exploring low-cost, highly active, and durable oxygen reduction catalysts is essential for the widespread use of proton exchange membrane fuel cells. Fe–N–C with nitrogen-coordinated single-atom (Fe–Nx) active sites are most promising candidates due to their highest activity in acid media among platinum-group-metal-free catalysts. However, application realistic cells still hindered by conundrum insufficient stability. This review focuses on understanding structure–stability relationship catalysts, which provides valuable guidance rational material design toward improved The significant achievements recent years discovery several site-specific degradation mechanisms identification intrinsically stable sites. development Fe-free also discussed as an alternative solution.

Language: Английский

---

Acidic oxygen evolution reaction: Mechanism, catalyst classification, and enhancement strategies

Interdisciplinary materials, Journal Year: 2023, Volume and Issue: 2(1), P. 53 - 90

Published: Jan. 1, 2023

Abstract As the most desirable hydrogen production device, highly efficient acidic proton exchange membrane water electrolyzers (PEMWE) are severely limited by sluggish kinetics of oxygen evolution reaction (OER) at anode. Rutile IrO 2 is a commercial acid‐stable OER catalyst with poor activity and high cost, which has motivated development alternatives. However, hitherto designed catalysts have disadvantages low or stability, cannot meet requirement industrial applications. Thus, exploring suitable strategies to enhance stability cost‐effective crucial for developing PEMWE technique. In this review, main mechanisms, different types catalysts, their characteristics summarized discussed, then possible improve proposed. Finally, problems prospects such generalized shed some light on future research advanced OER.

Language: Английский

---

Vacancy Defects Inductive Effect of Asymmetrically Coordinated Single‐Atom Fe─N₃S₁ Active Sites for Robust Electrocatalytic Oxygen Reduction with High Turnover Frequency and Mass Activity

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(11)

Published: Dec. 16, 2023

Abstract The development of facile, efficient synthesis method to construct low‐cost and high‐performance single‐atom catalysts (SACs) for oxygen reduction reaction (ORR) is extremely important, yet still challenging. Herein, an atomically dispersed N, S co‐doped carbon with abundant vacancy defects (NSC‐vd) anchored Fe single atoms (SAs) reported a inductive effect proposed promoting electrocatalytic ORR. optimized catalyst featured stable Fe─N 3 1 active sites exhibits excellent ORR activity high turnover frequency mass activity. In situ Raman, attenuated total reflectance surface enhanced infrared absorption spectroscopy reveal the exhibit different kinetic mechanisms in acidic alkaline solutions. Operando X‐ray spectra SAs/NSC‐vd electrolyte closely related coordination structure. Theoretical calculation reveals upshifted d band center facilitates adsorption O 2 accelerates kinetics process *OH reduction. around balance OOH* formation reduction, thus synergetically process.

Language: Английский

---

Review on the Degradation Mechanisms of Metal-N-C Catalysts for the Oxygen Reduction Reaction in Acid Electrolyte: Current Understanding and Mitigation Approaches

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(15), P. 9265 - 9326

Published: July 11, 2023

One bottleneck hampering the widespread use of fuel cell vehicles, in particular proton exchange membrane cells (PEMFCs), is high cost cathode where oxygen reduction reaction (ORR) occurs, due to current need precious metals catalyze this reaction. Electrochemists tackle issue short/medium term by developing catalysts with improved utilization or efficiency platinum, and longer term, based on Earth-abundant elements. Considerable progress has been achieved initial performance Metal-nitrogen-carbon (Metal-N-C) for ORR, especially Fe-N-C materials. However, until now, cannot be maintained a sufficiently long time an operating PEMFC. The identification mitigation degradation mechanisms Metal-N-C electrocatalysts acidic environment PEMFCs therefore become important research topic. Here, we review recent advances understanding electrocatalysts, including recently identified importance combined electrochemical potential. Results obtained liquid electrolyte PEMFC device are discussed, as well insights gained from situ operando techniques. We also approaches that scientific community hitherto investigated overcome durability issues electrocatalysts.

Language: Английский

---