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A new Co–Ni–N–C electrocatalyst for CO ₂ reduction, featuring diatomic metal-nitrogen sites on N-doped carbon, has been developed. It shows high CO yield and faradaic efficiency, promising for various electrochemical reactions.

In this report, the electrodeposition of Al from aluminum scrap alloys (A2020) on copper cathode substrates with varied surface roughness under different deposition temperatures was studied using low-temperature AlCl₃-1-butyl-3-methyl-imidazolium chloride (BMIC) ionic liquid electrolytes. The bulk electrodeposition of Al was carried out under a voltage of 1.5 V at a stirring rate of 120 rpm using a fixed ionic liquid electrolyte concentration (molar ratio AlCl₃: BMIC = 2:1). The effects of deposition temperature (range from 80 °C to 140 °C) and surface roughness of Cu cathode substrates (polished by 320, 600, 800, 1200 grits SiC sandpapers and mirror polishing process)more » on the morphology of deposited Al, current density, current efficiency and energy consumption, were investigated. The Al deposits were characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), profilometer, and electrochemical measurements for current density, current efficiency, and energy consumption. It is demonstrated that the deposition temperature and surface roughness of Cu electrodes play a critical role in the nucleation and growth of Al deposits. Higher deposition temperature promotes the diffusion and/or migration of Al₂Cl₇- ions and then enhances the current density and efficiency during the electrodeposition of Al. Smoother surface of Cu electrodes is preferred for the formation of dendrite-free Al deposits. Typically, on the mirror polished Cu electrode, no Al dendrite structure was observed, and only plate-like Al deposits were formed at the deposition temperature of 100 °C. Pure metallic Al was successfully deposited on Cu electrodes in AlCl₃+ BMIC ionic liquid electrolytes for all experiments with a current efficiency range from 72% to 99% and energy consumption of 4.6–6.3 kW h/kg Al.« less

Shape-engineered nanocrystals (SENs) promise a better selectivity and a higher activity in catalytic reactions than the corresponding non-shape-engineered ones because of their larger specific surface areas and desirable crystal facets. However, often, it is challenging to apply SENs in practical catalytic applications at high reaction temperatures, where SENs deforms into more stable, less active nanoparticles. In this paper, we show that atomic layer deposition (ALD) of Al₂O₃ at 200 °C can controllably dope Al cations into the shape-engineered CeO₂ nanorods (NRs) to not only increase their shape transition temperature from 400 °C to beyond 700 °C but also greatly increasemore » their specific reversible oxygen storage capacity (srOSC). Furthermore, the substituted Al3+ ions impede the surface diffusion of Ce ions and therefore improve the thermal stability of CeO₂ NRs. These Al3+ dopants form -Al–O–Ce–O– clusters, which are new Ce species and can be reversibly reduced and oxidized at 500–700 °C. This low-temperature chemical doping method decouples the synthesis process of SENs from the doping process and maintains the shape of the SENs during the activation of dopants. This concept could be adopted to enable the applications of other SENs in challenging high-temperature environments.« less

Here, ruthenium (Ru) catalysts supported on CeO₂ nanorods (NR), nanocubes (NC), and nanoctahedra (NO) were comparatively investigated to correlate the shape and exposed surface planes ({100}, {110}, and {111}) of nanoscale CeO₂ supports with their low-temperature CO oxidation activity. Within the 5Ru/CeO₂-r catalysts with three morphologies after reduction treatment, the Ru supported on CeO₂ NR exhibited enhanced low-temperature (<100 °C) hydrogen consumption and superior room-temperature CO oxidation activity (~9% CO conversion). Both X-ray photoelectron spectroscopy and X-ray absorption spectroscopy measurements revealed that Run+ homogeneously predominates the 5Ru/CeO₂NR-r, which is very different from partial metallic Ru⁰ supported on CeO₂ NC andmore » NO, indicating the strong metal–support interaction formation between Ru and CeO₂ NR by Ru ions diffusing into CeO₂ surface lattice or forming Ru–O–Ce bonds at the interface. The enriched surface defects on the exposed {111} planes of CeO₂ NR support are believed to be the key to the formation of cationic Ru species, which is of vital importance for the superior room-temperature CO oxidation activity of the 5Ru/CeO₂NR-r catalyst. The higher surface oxygen vacancy concentration on 5Ru/CeO₂NR-r than those on the CeO₂ NC and NO is also crucial for adsorption/dissociation of oxygen in achieving low-temperature CO oxidation activity.« less