Search

Using the one‐step flash evaporation technique, it is possible to deposit a film of methylammonium tin iodide (MASI, CH3NH3SnI3) from the solid perovskite powder that is prepared by a mechanochemical synthesis, without the use of any solvents. The source material and the film are characterized by X‐ray photoelectron spectroscopy (XPS) and X‐ray diffraction (XRD). The XPS measurements show that the MASI film is stoichiometric and is a p‐type material with the Fermi level of 0.4 eV above the valence band maximum (VBM) and a bandgap of 1.3 eV. The XRD pattern of the film reveals the formation of MASI perovskite of high purity, crystallizing with pseudo‐cubic symmetry, having the lattice parameters a ≈ c = 6.239(8) Å. [ABSTRACT FROM AUTHOR]

The chemical selectivity and faradaic efficiency of high-index Cu facets for the CO 2 reduction reaction (CO 2 RR) is investigated. More specifically, shape-controlled nanoparticles enclosed by Cu {hk0} facets are fabricated using Cu multilayer deposition at three distinct layer thicknesses on the surface facets of Au truncated ditetragonal nanoprisms (Au DTPs). Au DTPs are shapes enclosed by 12 high-index {310} facets. Facet angle analysis confirms DTP geometry. Elemental mapping analysis shows Cu surface layers are uniformly distributed on the Au {310} facets of the DTPs. The 7 nm Au@Cu DTPs high-index {hk0} facets exhibit a CH 4  : CO product ratio of almost 10 : 1 compared to a 1 : 1 ratio for the reference 7 nm Au@Cu nanoparticles (NPs). Operando Fourier transform infrared spectroscopy spectra disclose reactive adsorbed *CO as the main intermediate, whereas CO stripping experiments reveal the high-index facets enhance the *CO formation followed by rapid desorption or hydrogenation., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

In the urge of designing noble metal-free and sustainable electrocatalysts for oxygen evolution reaction (OER), herein, a mineral Digenite Cu 9 S 5 has been prepared from a molecular copper(I) precursor, [{(PyHS) 2 Cu I (PyHS)} 2 ](OTf) 2 (1), and utilized as an anode material in electrocatalytic OER for the first time. A hot injection of 1 yielded a pure phase and highly crystalline Cu 9 S 5 , which was then electrophoretically deposited (EPD) on a highly conducting nickel foam (NF) substrate. When assessed as an electrode for OER, the Cu 9 S 5 /NF displayed an overpotential of merely 298±3 mV at a current density of 10 mA cm -2 in alkaline media. The overpotential recorded here supersedes the value obtained for the best reported Cu-based as well as the benchmark precious-metal-based RuO 2 and IrO 2 electrocatalysts. In addition, the choronoamperometric OER indicated the superior stability of Cu 9 S 5 /NF, rendering its suitability as the sustainable anode material for practical feasibility. The excellent catalytic activity of Cu 9 S 5 can be attributed to the formation of a crystalline CuO overlayer on the conductive Cu 9 S 5 that behaves as active species to facilitate OER. This study delivers a distinct molecular precursor approach to produce highly active copper-based catalysts that could be used as an efficient and durable OER electro(pre)catalysts relying on non-precious metals., (© 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)