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Engineering interfacial hydrogen-bond network via cage-enabled soft confinement of Pt for facilitated hydrogen evolution kinetics
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).ORCID-id: 0000-0003-1016-5135
(Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Abstract [en]

The sluggish HER kinetics under alkaline conditions largely limit the development of alkaline water electrolysis. Decades of efforts have been reported to elucidate the origin of the pH dependence of HER kinetics and facilitate the alkaline HER kinetics. Apart from the widely concerned thermodynamic factors, the electrode process also depends unignorably on the kinetics of the electrochemical interface. Herein, we presented the facilitated HER kinetics by introducing porous amine cage-enabled confinement to Ptcatalyst to engineer the interface between the Pt surface and the aqueous electrolyte. In situ electrochemical surface-enhanced Raman spectra (SERS) measurements and ab initio molecular dynamics (AIMD) simulation jointly unveiled the fundamental interfacial interaction between water and cage that its -NH- moiety largely reduces the rigidity of the net of interfacial water H-bonds at negative HER potentials, which makes the net flexible enough to reorganize for better charge transfer. Our in-depth investigation pinpointed that the -NH- moiety acted as a proton pump and generated hydroxide transfer by forming and breaking H-bonds with interfacial water, refreshing the reactive water layer on the Pt surface. Our results address the crucial role of controllable interfacial kinetics during electrocatalytic reactions, and our strategy of establishing a soft-confining interfacial regulator offers a promising roadmap for manipulating electrocatalytic interfacial kinetics.

Nyckelord [en]
Hydrogen evolution kinetics, porous organic cage, charge transfer, in situ Raman, ab initio molecular dynamics
Nationell ämneskategori
Materialkemi
Identifikatorer
URN: urn:nbn:se:su:diva-225776OAI: oai:DiVA.org:su-225776DiVA, id: diva2:1830223
Forskningsfinansiär
Knut och Alice Wallenbergs Stiftelse, KAW 2022.0194Stockholms universitet, SU FV-2.1.1-005Tillgänglig från: 2024-01-22 Skapad: 2024-01-22 Senast uppdaterad: 2024-02-26Bibliografiskt granskad
Ingår i avhandling
1. Multiscale interfacial engineering of heterogeneous electrocatalysts: From structural design to mechanistic study
Öppna denna publikation i ny flik eller fönster >>Multiscale interfacial engineering of heterogeneous electrocatalysts: From structural design to mechanistic study
2024 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

In a typical heterogeneous electrocatalytic reaction, for the given active sites, the electronic structure plays a determining role in electron transfer between the active sites and reactant molecules, which impacts the reaction efficiency. Besides the electronic properties of the electrocatalysts, the reaction interface at which the charge transfer occurs plays an important role in the reaction kinetics. Moreover, the accessibility of the active sites to the reactant molecules also affects the reaction efficiency. However, a well-balanced effective strategy for electronic structure optimization that improves not only the activity but also stability and cost-effectiveness is needed. Besides, a robust model specifically tailored to investigate the kinetics of the electrocatalytic reaction is required to exclude the interference of thermodynamic factors. A feasible characterization technique for probing the complex interfacial process is also required.

 

To address these remaining challenges in the three aspects above, this thesis proposed the strategies to optimize the electrocatalytic reaction processes as follows:

 

(1) Tuning the electronic structure of the active sites by engineering coordination environment and introducing strain effect. Specifically, Ni single atom was constructed to engineer the coordination environment, and the electrocatalytic performance with the tuned electronic structure was examined towards hydrazine oxidation reaction. The strain effect was created by introducing Cu single atom to BiOCl substrate, and the optimized electronic structure was investigated;

(2) Optimizing the interfacial HER kinetics targeted by proposing a specific Pt model catalyst with a channel-opening modifier. The interfacial water structure was studied by in situ surface-enhanced Raman technique, and the role of this promoting modifier was elucidated by ab initio molecular dynamic simulation;

(3) Improving the local concentration of CO2 for electrochemical CO2 reduction reaction with a poly(ionic liquid) modifier, with Au as the model catalyst and the targeted characterization techniques.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Materials and Environmental Chemistry, Stockholm University, 2024. s. 71
Nyckelord
heterogeneous electrocatalysis, electronic structure, coordination environment, single-atom catalysts, strain effect, hydrogen evolution reaction kinetics, charge transfer, electrochemical CO^2 reduction, local enrichment
Nationell ämneskategori
Materialkemi
Forskningsämne
materialkemi
Identifikatorer
urn:nbn:se:su:diva-225784 (URN)978-91-8014-647-0 (ISBN)978-91-8014-648-7 (ISBN)
Disputation
2024-03-06, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (Engelska)
Opponent
Handledare
Tillgänglig från: 2024-02-12 Skapad: 2024-01-22 Senast uppdaterad: 2024-02-02Bibliografiskt granskad

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Zhou, ShiqiYuan, Jiayin

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