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MXene‐supported noble metal alloy catalysts exhibit remarkable electrocatalytic activity in various applications. However, there is no facile one‐step method for synthesizing these catalysts, because the synthesis of MXenes requires a strongly oxidizing environment and the preparation of platinum nanoalloys requires a strongly reducing environment and high temperatures. Hence, achieving coupling in one step is extremely challenging. In this paper, a straightforward one‐step molten salt method for preparing MXene‐supported platinum nanoalloy catalysts is proposed. The molten salt acts as the reaction medium to dissolve the transition metals and platinum ions at high temperatures. Transition metal ions oxidize the A‐site element from its MAX precursor at high temperatures, and the resulting transition metals further reduce platinum ions to form alloys. By coupling Al oxidation and platinum ion reduction using a molten salt solvent, this method directly converts Ti3AlC2 to a Pt‐M@Ti3C2Tx catalyst (where M denotes the transition metal). It further offers the possibility of extending the Pt‐M phase to binary, ternary, or quaternary platinum‐containing nanoalloys and converting the Al‐containing MAX phase to Ti2AlC and Ti3AlCN. Due to the strong interfacial interaction, the as‐prepared Pt‐Co@Ti3C2Tx is superior to commercial Pt/C (20 wt.%) in the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

CeO2-based surface modification is established as an effective strategy for improving the electrochemical performance of solid oxide electrolysis cells (SOECs), but the relevant mechanism has not been fully explored yet. Here, we employ focused ion beam-scanning electron microscopy to examine the microstructural evolution of bare nickel-based yttrium-stabilized zirconia (Ni/YSZ) electrode (reference cell) and Gd-doped CeO2 (CGO)-infiltrated Ni/YSZ electrode (optimized cell) before and after 100-h durability test. The initial current density of the optimized cell was 1.16 A cm−2 (at 1.3 V), which was 1.5 times larger than that of the reference cell. The voltage of the reference cell degraded dramatically due to a 1.16% reduction in the volume fraction of Ni, while the optimized cell showed a negligible degradation with a minor change in the volume fraction of Ni. It was confirmed that CGO nanoparticles formed a protective layer on the Ni surface during the electrolysis process, which prevented further evaporation of Ni. Overall, the infiltration of CGO into traditional Ni/YSZ electrode prevented decrease in the triple-phase boundary density and reduced the resistance by providing additional active sites for hydrogen evolution reaction. We believe that this work provides an efficient strategy for developing high-performance and long-term stable SOECs. [ABSTRACT FROM AUTHOR]

The structural diversity and tunable functionality of the amorphous metal‐organic frameworks (aMOFs) highlights this class of materials as a promising candidate for the development of sustainable energy technologies. The electrocatalytic performance in oxygen evolution reaction (OER) can be greatly improved by incorporating the hetero‐metallics into MOFs. Herein, the OER performance was significantly improved by the incorporation of Fe3+ ions into the crystalline cobalt‐based MOF, leading to amorphous structure. Benefiting from the optimized surface morphology and electrochemical surface area, charge transport, was greatly facilitated. The Fe/Co aMOF with 1/4 ratio (labeled as AFC‐MOFs (1 : 4)) exhibited an excellent and stable OER activity, with an ultralow overpotential (256 mV at 10 mA cm−2) and Tafel slope of 42.7 mV dec−1. XAS found that the majority of Co2+ in AFC‐MOFs (1 : 4) is converted to low‐spin Co3+ upon OER, while Fe3+ is maintained during the OER process, supporting the synergistic catalytic mechanism between Fe and Co. This material outperforms benchmark IrO2, which could be attributed to the hollow amorphous structure and the optimized electronic properties. [ABSTRACT FROM AUTHOR]

Keywords: Amorphous materials; Bimetallic MOFs; Electrocatalysts; Oxygen evolution reaction EN Amorphous materials Bimetallic MOFs Electrocatalysts Oxygen evolution reaction 688 688 1 03/02/21 20210225 NES 210225 B The Front Cover b shows how the cobalt-based MOF is transformed from a crystalline structure to an amorphous structure by incorporation of optimal Fe SP 3+ sp ions. Front Cover: A Tunable Amorphous Heteronuclear Iron and Cobalt Imidazolate Framework Analogue for Efficient Oxygen Evolution Reactions (Eur. J. Inorg. Amorphous materials, Bimetallic MOFs, Electrocatalysts, Oxygen evolution reaction. [Extracted from the article]

The two-dimensional molybdenum carbide (Mo 2 CT x) has a similar electronic structure to platinum, which has the potential to be one of non-precious metals catalysts for hydrogen evolution reaction (HER). However, the preparation of Mo 2 CT x by conventional HF and LiF–HCl etching method inevitably introduces the –F and –Cl terminations on the surface, which adversely affect activity and stability. In this study, the LiCl–KCl–Li 3 N molten salt was used to treat Mo 2 CT x at 600 °C and atmospheric pressure and introduce nitrogen heteroatoms. After treated in LiCl–KCl–Li 3 N molten salt, the HER performance of nitrogen-doped Mo 2 CT x is improved compared with that of un-doped Mo 2 CT x , which should be attributed to the optimization of the electronic structure of N–Mo 2 CT x and lower hydrogen adsorption energy barrier. This simple molten salt method provides a way to modify non-precious metal HER catalyst and introduce nitrogen heteroatoms. The LiCl–KCl–Li 3 N molten salt was used to treat Mo 2 CT x at 600 °C and atmospheric pressure and introduce nitrogen heteroatoms. After treatment in LiCl–KCl–Li 3 N molten salt, the HER performance of nitrogen-doped Mo 2 CT x is improved compared with that of un-doped Mo 2 CT x , which should be attributed to the optimization of the electronic structure of N–Mo 2 CT x and lower hydrogen adsorption energy barrier. [Display omitted] • N-modified Mo 2 CT x MXene was prepared via molten salt modification strategy. • The N doping optimizes the electronic structure of Mo 2 CT x. • The improved catalytic performance and stability for Mo 2 CT x. • The molten salt method is simple, efficient, cost-effective, and environmentally friendly for modification. [ABSTRACT FROM AUTHOR]

Developing efficient electrocatalyst at large current densities to meet the requirement of industrial water splitting is a big challenge today. Herein, we report a class of catalyst, BiCoO 3 with pyramidally coordinated Co3+. BiCoO 3 exhibits a large current density of 1000 mA cm−2 at a low overpotential of 402 mV and the overpotential even reduces to only 303 mV to achieve 1000 mA cm−2 by replacing Co with Fe, which belongs to the first-class level among large-current-densities electrocatalysts reported so far. Different from artificially created oxygen vacancies to optimize the bonding strength of the intermediate for enhancement of OER activity, BiCoO 3 has the rich active sites and the shortest reaction pathway leading to a large current density, as structurally every Co-O cluster has one oxygen vacancy. This work opens a new avenue for enhanced OER activity at high current densities via optimizing the arrangement of ligand vacancies. [Display omitted] • The first in-depth study of BiCoO 3 perovskite with pyramidally coordinated Co3+ in the water oxidation reaction. • The OER performance of BCFO belongs to the first-class level among large-current-densities electrocatalysts reported so far. • BiCoO 3 has the rich active sites and the shortest reaction pathway leading to an extraordinary large current density. [ABSTRACT FROM AUTHOR]