Operando studies reveal active Cu nanograins for CO2 electroreduction

Nature, Год журнала: 2023, Номер 614(7947), С. 262 - 269

Опубликована: Фев. 8, 2023

Язык: Английский

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Revealing the role of interfacial water and key intermediates at ruthenium surfaces in the alkaline hydrogen evolution reaction

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Авг. 30, 2023

Ruthenium exhibits comparable or even better alkaline hydrogen evolution reaction activity than platinum, however, the mechanistic aspects are yet to be settled, which elucidated by combining in situ Raman spectroscopy and theoretical calculations herein. We simultaneously capture dynamic spectral evidence of Ru surfaces, interfacial water, *H *OH intermediates. surfaces exist different valence states potential range, dissociating water differently generating two distinct *H, resulting activities. The local cation tuning effect hydrated Na+ ion large work function high-valence Ru(n+) promote dissociation. Moreover, compared low-valence Ru(0) have more moderate adsorption energies for *OH. They, therefore, facilitate activity. Our findings demonstrate regulation state on intermediates, finally catalytic activity, provide guidelines rational design high-efficiency catalysts.

Язык: Английский

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Engineering Water Molecules Activation Center on Multisite Electrocatalysts for Enhanced CO₂ Methanation

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(28), С. 12807 - 12815

Опубликована: Июль 5, 2022

The renewable energy-powered electrolytic reduction of carbon dioxide (CO2) to methane (CH4) using water as a reaction medium is one the most promising paths store intermittent energy and address global sustainability problems. However, role in electrolyte often overlooked. In particular, slow dissociation kinetics limits proton-feeding rate, which severely damages selectivity activity methanation process involving multiple electrons protons transfer. Here, we present novel tandem catalyst comprising Ir single-atom (Ir1)-doped hybrid Cu3N/Cu2O multisite that operates efficiently converting CO2 CH4. Experimental theoretical calculation results reveal Ir1 facilitates into proton feeds sites for *CO protonation pathway toward *CHO. displays high Faradaic efficiency 75% CH4 with current density 320 mA cm-2 flow cell. This work provides strategy rational design high-efficiency catalytic systems.

Язык: Английский

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Orbital Occupancy and Spin Polarization: From Mechanistic Study to Rational Design of Transition Metal-Based Electrocatalysts toward Energy Applications

ACS Nano, Год журнала: 2022, Номер 16(11), С. 17847 - 17890

Опубликована: Окт. 31, 2022

Over the past few decades, development of electrocatalysts for energy applications has extensively transitioned from trial-and-error methodologies to more rational and directed designs at atomic levels via either nanogeometric optimization or modulating electronic properties active sites. Regarding modulation properties, nonprecious transition metal-based materials have been attracting large interest due capability versatile tuning d-electron configurations expressed through flexible orbital occupancy various possible degrees spin polarization. Herein, recent advances in tailoring transition-metal atoms intrinsically enhanced electrocatalytic performances are reviewed. We start with discussions on how polarization can govern essential level processes, including transport electron charge bulk, reactive species adsorption catalytic surface, transfer between centers adsorbed as well reaction mechanisms. Subsequently, different techniques currently adopted structures discussed particular emphasis theoretical rationale practical achievements. also highlight promises recently established computational design approaches developing applications. Lastly, discussion is concluded perspectives current challenges future opportunities. hope this review will present beauty structure–activity relationships catalysis sciences contribute advance conversion

Язык: Английский

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Band Gap Narrowing in a High-Entropy Spinel Oxide Semiconductor for Enhanced Oxygen Evolution Catalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(12), С. 6753 - 6761

Опубликована: Март 15, 2023

High-entropy oxides (HEOs), which contain five or more metal cations that are generally thought to be randomly mixed in a crystalline oxide lattice, can exhibit unique and enhanced properties, including improved catalytic performance, due synergistic effects. Here, we show band gap narrowing emerges high-entropy aluminate spinel oxide, (Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)Al2O4 (A5Al2O4). The 0.9 eV of A5Al2O4 is narrower than the gaps all parent oxides. First-principles calculations for multicomponent AAl2O4 spinels indicate arises from broadening energy distribution 3d states variations electronegativities crystal field splitting across transition-metal series. As catalyst oxygen evolution reaction an alkaline electrolyte, reaches current density 10 mA/cm2 at overpotential 400 mV, outperforming single-metal end members applied potential 1.7 V vs RHE. Catalyst deactivation occurs after 5 h attributed, based on elemental analysis grazing-incidence X-ray diffraction, formation passivating layer blocks surface. This result helps validate HEO active catalyst. observation expands scope properties exhibited by materials offers insight into question how electronic structure engineered via approach achieve properties.

Язык: Английский

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High performance poly(carbazolyl aryl piperidinium) anion exchange membranes for alkaline fuel cells

Journal of Membrane Science, Год журнала: 2022, Номер 657, С. 120676 - 120676

Опубликована: Май 28, 2022

Язык: Английский

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High‐performance Poly(biphenyl piperidinium) Type Anion Exchange Membranes with Interconnected Ion Transfer Channels: Cooperativity of Dual Cations and Fluorinated Side Chains

Advanced Functional Materials, Год журнала: 2023, Номер 33(35)

Опубликована: Май 5, 2023

Abstract The performance of alkaline fuel cells is severely limited by substandard anion exchange membranes (AEMs) due to the lower ionic conductivity compared proton membranes. AEMs can be effectively improved regulating microphase structure, but it still cannot meet practical use requirements. Here, enhanced microphase‐separated structures are constructed cooperativity highly hydrophilic dual cations and hydrophobic fluorinated side chains. Meanwhile, introduction O enhances flexibility chains facilitates formation ion transport channels. piperidinium cation functionalized membrane (PB2Pip‐5C8F) which grafted with ultra‐hydrophobic fluorocarbon chain exhibits a high 74.4 mS cm −1 at 30 °C 168.46 80 °C. Furthermore, PB2Pip‐5C8F achieves highest peak power density 718 mW −2 under current 1197 mA without back pressure. A long‐term life cell test this AEM shows low voltage decay rate 1.68 mV h over 70 operation

Язык: Английский

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Membrane Electrode Assembly for Electrocatalytic CO₂ Reduction: Principle and Application

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(28)

Опубликована: Март 27, 2023

Abstract Electrocatalytic CO 2 reduction reaction (CO RR) in membrane electrode assembly (MEA) systems is a promising technology. Gaseous can be directly transported to the cathode catalyst layer, leading enhanced rate. Meanwhile, there no liquid electrolyte between and anode, which help improve energy efficiency of whole system. The remarkable progress achieved recently points out way realize industrially relevant performance. In this review, we focus on principles MEA for RR, focusing gas diffusion electrodes ion exchange membranes. Furthermore, anode processes beyond oxidation water are considered. Besides, voltage distribution scrutinized identify specific losses related individual components. We also summarize generation different reduced products together with corresponding catalysts. Finally, challenges opportunities highlighted future research.

Язык: Английский

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Intermetallic Nanocrystals for Fuel-Cells-Based Electrocatalysis

Chemical Reviews, Год журнала: 2023, Номер 123(22), С. 12507 - 12593

Опубликована: Ноя. 1, 2023

Electrocatalysis underpins the renewable electrochemical conversions for sustainability, which further replies on metallic nanocrystals as vital electrocatalysts. Intermetallic have been known to show distinct properties compared their disordered counterparts, and long explored functional improvements. Tremendous progresses made in past few years, with notable trend of more precise engineering down an atomic level investigation transferring into practical membrane electrode assembly (MEA), motivates this timely review. After addressing basic thermodynamic kinetic fundamentals, we discuss classic latest synthetic strategies that enable not only formation intermetallic phase but also rational control other catalysis-determinant structural parameters, such size morphology. We demonstrate emerging nanomaterials potentially advancement energy electrocatalysis. Then, state-of-the-art characterizations representative electrocatalysts emphasis oxygen reduction reaction evaluated a MEA setup. summarize review by laying out existing challenges offering perspective future research directions toward practicing conversions.

Язык: Английский

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A completely precious metal–free alkaline fuel cell with enhanced performance using a carbon-coated nickel anode

Proceedings of the National Academy of Sciences, Год журнала: 2022, Номер 119(13)

Опубликована: Март 21, 2022

Significance We present a groundbreaking advance in completely nonprecious hydrogen fuel cell technologies achieving record power density of 200 mW/cm 2 with Ni@CN x anode and Co−Mn cathode. The 2-nm CN coating weakens the O-binding energy, which effectively mitigates undesirable surface oxidation during reaction (HOR) polarization, leading to stable operation for over 100 h at mA/cm , superior Ni nanoparticle counterpart. Ni@CNx exhibited dramatically enhanced tolerance CO relative Pt/C, enabling use gas trace amounts CO, critical practical applications. complete removal precious metals cells lowers catalyst cost virtually negligible levels marks milestone alkaline cells.

Язык: Английский

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