Electrocatalytic reduction of CO2 into alcohols of high economic value offers a promising route to realize resourceful CO2 utilization. In this study, we choose three model bicentric copper complexes based on the expanded and fluorinated porphyrin structure, but different spatial and coordination geometry, to unravel their structure-property-performance correlation in catalyzing electrochemical CO2 reduction reactions. We show that the complexes with higher intramolecular tension and coordination asymmetry manifests a lower electrochemical stability and thus more active Cu centers, which can be reduced during electrolysis to form Cu clusters accompanied by partially-reduced or fragmented ligands. We demonstrate the hybrid structure of Cu cluster and partially reduced O-containing hexaphyrin ligand is highly potent in converting CO2 into alcohols, up to 32.5% ethanol and 18.3% n-propanol in Faradaic efficiencies that have been rarely reported. More importantly, we uncover an interplay between the inorganic and organic phases to synergistically produce alcohols, of which the intermediates are stabilized by a confined space to afford extra O-Cu bonding. This study underlines the exploitation of structure-dependent electrochemical property to steer the CO2 reduction pathway, as well as a potential generic tactic to target alcohol synthesis by constructing organic/inorganic Cu hybrids.
The development of high‐performance multifunctional electrocatalysts operating in the same electrolyte is key to reduce the material and process costs of renewable energy conversion and storage devices. Herein, the fabrication of freestanding integral electrodes by combining multivariate electrospinning with surface metal organic framework functionalization to arrest pyrolytic emissions from fiber interior is reported, resulting in the expression of rich active sites with controlled composition, for example, the tunable Co‐P coordination. The as‐fabricated electrode of CoP@CF‐900, when used as both the cathode and anode for overall water splitting, is able to deliver 200 mA cm−2 at a cell voltage of 1.89 V, significantly outshining the Pt/C‖RuO2 couple; when used as the air cathode for a zinc‐air battery, is able to operate more than 150 h at 10 mA cm−2 with a nearly constant round‐trip energy efficiency of ≈60%, also outperforming the Pt/C+RuO2 benchmark. The activity and kinetics origin of the superb multi‐functionality is further elucidated through extensive electroanalytical, post‐mortem, and operando characterizations, which underscore the construction of robust integral electrodes through synergistic structure and composition engineering.
The performance of lithium-metal batteries is severely hampered by uncontrollable dendrite growth and volume expansion on the metal anodes. Inspired by the "blockchain" concept in data mining, here we utilize a conductive polymer-filled metal-organic framework (MOF) as the lithium host, in which polypyrrole (PPy) serves as the "chain" to interlink Li "blocks" stored in the MOF pores. While the N-rich PPy guides fast Li + infiltration/extrusion and serves as the nucleation sites for isotropic Li growth, the MOF pores compartmentalize bulk Li deposition for 3D matrix Li storage, leading to low-barrier and dendrite-free Li plating/stripping with superb Coulombic efficiency. The asfabricated lithium-metal anodes operate over 700 cycles at 5 mA cm À 2 in symmetric cells, and 800 cycles at 1 C in full cells with a per-cycle capacity loss of only 0.017 %. This work might open a new chapter for Li-metal anode construction by introducing the concept of "blockchain" management of Li plating/stripping.
Heteroatomic modulation of MnO 2 is an effective way to introduce and tailor the catalytically active sites for electrochemical water oxidation. While great efforts have been devoted to parsing the configuration and coordination of dopants in dictating the catalytic activity, less is considered about the feedback from the structurally adapted MnO 2 host to the intrinsic activity of catalytic sites. In this study, the topological effect on oxygen evolution reaction (OER) activity was systemically investigated for partially Ru-substituted MnO 2 of various polymorphs. We show that MnO 2 of different porosities responds differently to the Ru integration, thereby resulting in varied lattice strains and morphological changes. While the highly porous τ-MnO 2 undergoes amorphization upon Ru substitution, the closely packed β-MnO 2 suffers crystal splintering with drastically enhanced structural defects, which lends to a low OER overpotential of 278 mV at 10 mA cm −2 and a high turnover frequency of 2022.2 h −1 that is 19.6fold higher than that of the commercial RuO 2 benchmark. Therefore, the integration of Ru does not simply append active sites to the relatively inert metal oxides but simultaneously modifies the crystal structure of MnO 2 to retroactively modulate the catalytic activity. We further show that OER on the Ru-substituted β-MnO 2 follows a lattice oxygen mechanism as a result of the adapted oxide substrate. This study furnishes a fresh and systemic view on the dopant−substrate interplay for modulating the electrocatalytic activity of tunneled MnO 2 structures.
As the promising next‐generation energy storage solution, lithium metal battery (LMB) has gained great attention but still suffers from troubles associated with the highly active metallic lithium. Herein, it is aimed to develop an anode‐free LMB engaging no Li disk or foil by modifying the Cu current collector with mercapto metal–organic frameworks (MOFs) impregnating Ag nanoparticles (NPs). While the polar mercapto groups facilitate and guide Li+ transport, the highly lithiophilic Ag NPs help to enhance the electric conductivity and lower the energy barrier of Li nucleation. Furthermore, the MOF pores allow compartmentalizing bulk Li into a 3D matrix Li storage so that not only the local current density is reduced, but also is the plating/stripping reversibility greatly enhanced. As a result, full cells pairing the prelithiated Ag@Zr‐DMBD/Cu anodes with LiFePO4 cathodes demonstrate a high initial specific capacity of 159.8 mAh g−1, first‐cycle Coulombic efficiency of 96.6%, and long‐term cycling stability over 1000 cycles with 99.3% capacity retention at 1 C. This study underlines the multi‐aspect functionalization of MOFs to impart lithiophilicity, polarity, and porosity to achieve reversible Li plating/stripping and paves the way for realizing high‐performance anode‐free LMBs through exquisite modification of the Cu current collector.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.