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.

Gold nanoparticles where synthesized and supported on carbon, or directly synthesized on carbon according to five different methods reported in literature, aiming at particles<10 nm. Characterization was done with transmission electron microscopy and thermogravimetric analysis. Although all syntheses yielded particles with an average diameter<10 nm, the formation of few very large particles, where a relatively large amount of Au is buried, as well as loss during the supporting procedure led to the exclusion of four of the five tested methods for further studies. The most promising AuNPs supported on carbon where tested for the methanol electrooxidation (MEO) in alkaline media. Four different Au‐loadings where realized, and supporting led to moderate particle growth depending on the loading. To compare MEO activity of the samples with different Au‐loadings a conversion factor was developed where the MEO activity can be compared in terms of NP size and Au‐loading.

We report on the new Ruddlesden–Popper (RP) oxyfluoride La2NiO2.5F3 containing an unprecedented high amount of fluorine and Ni2+. This oxyfluoride was prepared by topochemical low-temperature fluorination of La2NiO4, which was obtained by a soft chemistry synthesis, with poly­(vinylidene difluoride) (PVDF) as fluorinating agent. La2NiO2.5F3 is the first n = 1 RP compound crystallizing in the tetragonal space group P42/nnm (a = 5.7297(6) Å and c = 13.0106(2) Å). The crystal structure shows a unique tilting scheme of the NiO4F2 octahedra that has so far been only theoretically predicted. Combined neutron and X-ray powder diffraction experiments together with bond-valence-sum and DFT+U calculations reveal an unusual anion ordering with fluoride being located on the apical anion sites of the NiO4F2 octahedra. Excess fluorine ions were found to populate two of the four interstitial anion sites in an ordered fashion. A third interstitial anion position is occupied by oxygen ions while the fourth site remains unoccupied. This hitherto unobserved ordering scenario in RP oxyfluorides promotes a strong layerwise alternating tilting of the NiO4F2 octahedra. Magnetic measurements show strong antiferromagnetic interactions with a high Néel temperature of about 225 K and a pronounced ZFC/FC splitting most likely as the result of a small ferromagnetic moment arising from spin canting. The electronic structure was characterized by DFT and UV–vis spectroscopy, and a strong increase of E g was found compared to La2NiO4 (3.4 eV vs 1.3 eV).

Gold nanoparticles < 10 nm in size are typially prepared using stabilizing agents, e.g. thiolates. Often standard recipes from literature are used to presumably remove these stabilisers to liberate the...

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