Isolated copper–tin atomic interfaces tuning electrocatalytic CO2 conversion

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: March 4, 2021

Abstract Direct experimental observations of the interface structure can provide vital insights into heterogeneous catalysis. Examples design based on single atom and surface science are, however, extremely rare. Here, we report Cu–Sn single-atom alloys, where isolated Sn sites with high densities (up to 8%) are anchored Cu host, for efficient electrocatalytic CO 2 reduction. The unique geometric electronic alloys (Cu 97 3 99 1 ) enables distinct catalytic selectivity from pure 100 70 30 bulk alloy. catalyst achieves a Faradaic efficiency 98% at tiny overpotential mV in an alkaline flow cell, current density mA cm −2 is obtained 340 mV. Density functional theory simulation reveals that it not only elemental composition dictates reactivity alloys; local coordination environment atomically dispersed, bonding plays most critical role.

Language: Английский

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Toward Electrocatalytic Methanol Oxidation Reaction: Longstanding Debates and Emerging Catalysts

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(26)

Published: Jan. 27, 2023

The study of direct methanol fuel cells (DMFCs) has lasted around 70 years, since the first investigation in early 1950s. Though enormous effort been devoted this field, it is still far from commercialization. oxidation reaction (MOR), as a semi-reaction DMFCs, bottleneck that restricts overall performance DMFCs. To date, there intense debate on complex six-electron reaction, but barely any reviews have systematically discussed topic. end, controversies and progress regarding electrocatalytic mechanisms, evaluations well design science toward MOR electrocatalysts are summarized. This review also provides comprehensive introduction recent development emerging with focus innovation alloy, core-shell structure, heterostructure, single-atom catalysts. Finally, perspectives future outlook mechanisms provided.

Language: Английский

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Self-Assembly of Ir-Based Nanosheets with Ordered Interlayer Space for Enhanced Electrocatalytic Water Oxidation

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(5), P. 2208 - 2217

Published: Jan. 31, 2022

Iridium (Ir)-based electrocatalysts are widely explored as benchmarks for acidic oxygen evolution reactions (OERs). However, further enhancing their catalytic activity remains challenging due to the difficulty in identifying active species and unfavorable architectures. In this work, we synthesized ultrathin Ir-IrOx/C nanosheets with ordered interlayer space enhanced OER by a nanoconfined self-assembly strategy, employing block copolymer formed stable end-merged lamellar micelles. The distance of prepared was well controlled at ∼20 nm Ir-IrOx nanoparticles (∼2 nm) were uniformly distributed within nanosheets. Importantly, fabricated display one lowest overpotential (η) 198 mV 10 mA cm-2geo during an acid medium, benefiting from features mixed-valence states, rich electrophilic (O(II-δ)-), favorable mesostructured Both experimental computational results reveal that mixed valence O(II-δ)- moieties 2D mesoporous catalysts shortened Ir-O(II-δ)- bond (1.91 Å) is key enhancement balancing adsorption free energy oxygen-containing intermediates. This strategy thus opens avenue designing high performance through water oxidation beyond.

Language: Английский

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Spectroelectrochemical Analysis of the Water Oxidation Mechanism on Doped Nickel Oxides

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(17), P. 7622 - 7633

Published: April 20, 2022

Metal oxides and oxyhydroxides exhibit state-of-the-art activity for the oxygen evolution reaction (OER); however, their mechanism, particularly relationship between charging of oxide OER kinetics, remains elusive. Here, we investigate a series Mn-, Co-, Fe-, Zn-doped nickel using operando UV-vis spectroscopy coupled with time-resolved stepped potential spectroelectrochemistry. The Ni2+/Ni3+ redox peak is found to shift anodically from Mn- < Co- Fe- samples, suggesting decrease in binding energetics samples. At OER-relevant potentials, optical absorption spectroscopy, quantitatively detect subsequent oxidation these centers. kinetics was have second-order dependence on density oxidized species, chemical rate-determining step involving coupling two oxo species. intrinsic turnover frequency per species exhibits volcano trend energy Ni site, having maximum ∼0.05 s-1 at 300 mV overpotential Fe-doped sample. Consequently, propose that centers bind too strongly (Mn- Co-doped oxides), limited by O-O desorption, while weakly (Zn-doped formation groups. This study not only experimentally demonstrates relation electroadsorption free this class materials but also highlights critical role facilitating kinetics.

Language: Английский

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Oxygen-Inserted Top-Surface Layers of Ni for Boosting Alkaline Hydrogen Oxidation Electrocatalysis

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(28), P. 12661 - 12672

Published: June 22, 2022

Precisely tailoring the electronic structures of electrocatalysts to achieve an optimum hydroxide binding energy (OHBE) is vital alkaline hydrogen oxidation reaction (HOR). As a promising alternative Pt-group metals, considerable efforts have been devoted exploring highly efficient Ni-based catalysts for HOR. However, their performances still lack practical competitiveness. Herein, based on insights from molecular orbital theory and Hammer-Nørskov d-band model, we propose ingenious surface oxygen insertion strategy precisely tailor Ni electrocatalysts, simultaneously increasing degree energy-level alignment between adsorbed (*OH) states decreasing anti-bonding filling, which leads optimal OHBE. Through pyrolysis procedure mediated by metal-organic framework at low temperature under reducing atmosphere, obtained oxygen-inserted two atomic-layer shell-modified metal core nanoparticle (Ni@Oi-Ni) exhibits remarkable HOR performance with record mass activity 85.63 mA mg-1, 40-fold higher than that freshly synthesized catalyst. Combining CO stripping experiments ab initio calculations, further reveal linear relationship OHBE content inserted oxygen, thus results in volcano-type correlation OH strength activity. This work indicates into top-surface layers regulate coordination environment structure identifies dominate role

Language: Английский

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