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Cu thin films and Cu2O microstructures were partially converted to the Metal‐Organic Frameworks (MOFs) Cu3(BTC)2 or Cu(TCPP) using an electrochemical process with a higher control and at milder conditions compared to the traditional solvothermal MOF synthesis. Initially, either a Cu thin film was sputtered, or different kinds of Cu or Cu2O microstructures were electrochemically deposited onto a conductive ITO glass substrate. Then, these Cu thin films or Cu‐based microstructures were subsequently coated with a thin layer of either Cu3(BTC)2 or Cu(TCPP) by controlled anodic dissolution of the Cu‐based substrate at room temperature and in the presence of the desired organic linker molecules: 1,3,5‐benzenetricarboxylic acid (BTC) or photoactive 4,4′,4′′,4′′′‐(Porphine‐5,10,15,20‐tetrayl) tetrakis(benzoic acid) (TCPP) in the electrolyte. An increase in size of the Cu micro cubes with exposed planes [100] of 38,7 % for the Cu2O@Cu3(BTC)2 and a 68,9 % increase for the Cu2O@Cu(TCPP) was roughly estimated. Finally, XRD, Raman spectroscopy and UV–vis absorption spectroscopy were used to characterize the initial Cu films or Cu‐based microstructures, and the obtained core‐shell Cu2O@Cu(BTC) and Cu2O@Cu(TCPP) microstructures. [ABSTRACT FROM AUTHOR]

Controlling the crystallization of Metal–Organic Frameworks (MOFs) at the nanoscale is currently challenging, and this hinders their utilization for multiple applications including photo(electro)chemistry and sensors. In this work, we show a synthetic protocol that enables the preparation of highly homogeneous Cu2O@MOF nanowires standing on a conductive support with extensive control over the crystallization of the MOF nanoparticles at the surface of the Cu2O nanowires. Cu2O nanowires were first prepared via templated electrodeposition, and then partially converted into the well-known Cu-MOF HKUST-1 by pulsed electrochemical oxidation. We show that the use of PVP as a capping agent during the electrochemical oxidation of Cu2O into HKUST-1 provides control over the growth of the MOF nanocrystals on the surface of the Cu2O nanowires, and that the size of the MOF crystals obtained can be tuned by changing the concentration of PVP dissolved in the electrolyte. In addition, we propose the use of benzoic acid as an alternative to achieve control over the size of the obtained MOF nanocrystals when the use of a capping agent should be avoided. [ABSTRACT FROM AUTHOR]

In this work, the simultaneous investigation of a single cuprous oxide microcrystal towards CO2 electroreduction (CRR, CO2 reduction reaction) by using Raman microscopy and scanning electrochemical microscopy (SECM) is shown. Cu2O microcrystals were electrochemically crystallized on an indium‐doped tin oxide‐substrate (ITO). Structural changes of the Cu2O microcrystal are observed in situ by Raman microcopy, which indicates their fast conversion into elemental Cu at low overpotentials. Simultaneously, detection of products of the CO2 reduction is carried out electrochemically using the sample‐generation tip‐collection mode (SG/TC) of SECM and formate ions are the main product of CRR, as detected by a 10 μm Pt ultramicroelectrode (UME). Thus, with our approach, the very beginning of the CRR (onset potential), potential‐dependent product formation as well as structural changes in the catalyst can be precisely investigated. [ABSTRACT FROM AUTHOR]

Keywords: carbon dioxide reduction; cuprous oxide; scanning electrochemical microscopy; Raman microscopy; in situ characterization EN carbon dioxide reduction cuprous oxide scanning electrochemical microscopy Raman microscopy in situ characterization 1 1 1 02/21/22 20220211 NES 220211 B The Cover Feature b illustrates the simultaneous probing of a cuprous oxide microcrystal by Raman and Scanning Electrochemical Microscopy (SECM) during CO SB 2 sb electro-reduction. Cover Feature: Probing Individual Cuprous Oxide Microcrystals towards Carbon Dioxide Reduction by using In Situ Raman-coupled Scanning Electrochemical Microscopy (ChemElectroChem 3/2022) Carbon dioxide reduction, cuprous oxide, scanning electrochemical microscopy, Raman microscopy, in situ characterization. [Extracted from the article]

Cu thin films and Cu 2 O microstructures were partially converted to the Metal-Organic Frameworks (MOFs) Cu 3 (BTC) 2 or Cu(TCPP) using an electrochemical process with a higher control and at milder conditions compared to the traditional solvothermal MOF synthesis. Initially, either a Cu thin film was sputtered, or different kinds of Cu or Cu 2 O microstructures were electrochemically deposited onto a conductive ITO glass substrate. Then, these Cu thin films or Cu-based microstructures were subsequently coated with a thin layer of either Cu 3 (BTC) 2 or Cu(TCPP) by controlled anodic dissolution of the Cu-based substrate at room temperature and in the presence of the desired organic linker molecules: 1,3,5-benzenetricarboxylic acid (BTC) or photoactive 4,4',4'',4'''-(Porphine-5,10,15,20-tetrayl) tetrakis(benzoic acid) (TCPP) in the electrolyte. An increase in size of the Cu micro cubes with exposed planes [100] of 38,7 % for the Cu 2 O@Cu 3 (BTC) 2 and a 68,9 % increase for the Cu 2 O@Cu(TCPP) was roughly estimated. Finally, XRD, Raman spectroscopy and UV-vis absorption spectroscopy were used to characterize the initial Cu films or Cu-based microstructures, and the obtained core-shell Cu 2 O@Cu(BTC) and Cu 2 O@Cu(TCPP) microstructures., (© 2023 The Authors. ChemPlusChem published by Wiley-VCH GmbH.)