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Abstract Cu catalyses electrochemical CO2 reduction to valuable multicarbon products but understanding the structure-function relationship has remained elusive due to the active Cu sites being heterogenized and under dynamic re-construction during electrolysis. We herein coordinate Cu with six phenyl-1H-1,2,3-triazole derivatives to form stable coordination polymer catalysts with homogenized, single-site Cu active sites. Electronic structure modelling, X-ray absorption spectroscopy, and ultraviolet–visible spectroscopy show a widely tuneable Cu electronics by modulating the highest occupied molecular orbital energy of ligands. Using CO diffuse reflectance Fourier transform infrared spectroscopy, in-situ Raman spectroscopy, and density functional theory calculations, we find that the binding strength of *CO intermediate is positively correlated to highest occupied molecular orbital energies of the ligands. As a result, we enable a tuning of C–C coupling efficiency—a parameter we define to evaluate the efficiency of C2 production—in a broad range of 0.26 to 0.86. This work establishes a molecular platform that allows for studying structure-function relationships in CO2 electrolysis and devises new catalyst design strategies appliable to other electrocatalysis.

Gallium and gallium alloys have gained significant interest due to gallium's low melting point. This property allows for gallium‐based catalysts to take advantage of the unique reaction environments only available in the liquid state. While understanding of the catalytic properties of liquid metals is emerging, a comprehensive investigation into the fundamental structures of these materials has yet to be undertaken. Herein, the structure of liquid gallium, along with related liquid alloys EGaIn, EGaSn, and Galinstan are explored using X‐ray absorption spectroscopy (XAS). In contrast to some other studies that show dimers, analysis of the XAS data both in X‐ray absorption near edge structure and extended X‐ray absorption fine structure shows that when fully dissolved the materials are largely homogenous with no obvious signs of local structures. Ga shows a bond contraction when melted which is consistent with its increase in density; however, an expansion in bond length is observed when alloyed with In and Sn. XAS data indicate that the effective nuclear charge (Zeff) of In and Sn follows the trend expected based on electronegativity. Molecular dynamic (MD) simulations are performed to simulate the structure and trends between MD and XAS; the trends agree well but MD overestimates bond lengths.

Abstract In this work, 2D ferromagnetic M3GeTe2 (MGT, M = Ni/Fe) nanosheets with rich atomic Te vacancies (2D‐MGTv) are demonstrated as efficient OER electrocatalyst via a general mechanical exfoliation strategy. X‐ray absorption spectra (XAS) and scanning transmission electron microscope (STEM) results validate the dominant presence of metal‐O moieties and rich Te vacancies, respectively. The formed Te vacancies are active for the adsorption of OH* and O* species while the metal‐O moieties promote the O* and OOH* adsorption, contributing synergistically to the faster oxygen evolution kinetics. Consequently, 2D‐Ni3GeTe2v exhibits superior OER activity with only 370 mV overpotential to reach the current density of 100 mA cm−2 and turnover frequency (TOF) value of 101.6 s−1 at the overpotential of 200 mV in alkaline media. Furthermore, a 2D‐Ni3GeTe2v‐based anion‐exchange membrane (AEM) water electrolysis cell (1 cm2) delivers a current density of 1.02 and 1.32 A cm−2 at the voltage of 3 V feeding with 0.1 and 1 m KOH solution, respectively. The demonstrated metal‐O coordination with abundant atomic vacancies for ferromagnetic M3GeTe2 and the easily extended preparation strategy would enlighten the rational design and fabrication of other ferromagnetic materials for wider electrocatalytic applications.

Abstract A practical high-specific-energy Li metal battery requires thin (≤20 μm) and free-standing Li metal anodes, but the low melting point and strong diffusion creep of lithium metal impede their scalable processing towards thin-thickness and free-standing architecture. In this paper, thin (5 to 50 μm) and free-standing lithium strips were achieved by mechanical rolling, which is determined by the in situ tribochemical reaction between lithium and zinc dialkyldithiophosphate (ZDDP). A friction-induced organic/inorganic hybrid interface (~450 nm) was formed on Li with an ultra-high hardness (0.84 GPa) and Young’s modulus (25.90 GPa), which not only enables the scalable process mechanics of thin lithium strips but also facilitates dendrite-free lithium metal anodes by inhibiting dendrite growth. The rolled lithium anode exhibits a prolonged cycle lifespan and high-rate cycle stability (in excess of more than 1700 cycles even at 18.0 mA cm−2 and 1.5 mA cm−2 at 25 °C). Meanwhile, the LiFePO4 (with single-sided load 10 mg/cm2) ||Li@ZDDP full cell can last over 350 cycles with a high-capacity retention of 82% after the formation cycles at 5 C (1 C = 170 mA/g) and 25 °C. This work provides a scalable approach concerning tribology design for producing practical thin free-standing lithium metal anodes.

When used to promote the oxygen evolution reaction (OER), transition‐metal chalcogenides convert into oxyhydroxide/(hydr)oxide catalysts, the performance of which depends on the properties of the precursor. The present study aims to explore these effects for cobalt and cobalt–iron selenides (CoSe n and Co1Fe1Se n ) prepared using a simple microwave‐assisted method, in comparison to a reference material synthesized by high‐temperature reaction of CoO x H y with Se vapors. Physical characterization of the microwave‐synthesized CoSe n demonstrates their sheet‐like morphology and identifies Co3Se4 as the major phase, which is essentially completely transformed into CoOOH during the OER. The temperature during the microwave‐assisted CoSe n synthesis affects the crystallinity, the electrochemically active surface area, and thereby the performance of the resulting catalysts. Further improvements in the activity are achieved by combining cobalt with iron into a bimetallic Co1Fe1Se n precursor, which transforms in situ into a CoOOH + FeOOH composite and sustains the OER rate of 100 mA cm−2 (33 A g−1) at an overpotential of ≈ 0.31 and 0.26 V at 24 ± 2 and 80 ± 1 °C, respectively. Satisfactory stability of the Co1Fe1Se n ‐derived electrodes is demonstrated through a 4‐day‐long test at 80 ± 1 °C and 100 mA cm−2.

Selective two-electron oxygen reduction reaction is critical electrochemical process for H2O2 electrosynthesis. Here, the authors develop a Sb2S3-templated strategy to fabricate high-density atomic dispersion of Sb on N,S-codoped hollow carbon nanofiber substrate, which facilitate with the improved selectivity, catalytic mass activity and production rate of H2O2.

The most accurate measurements of the mass attenuation coefficient for metals at low temperature for the zinc K-edge from 9.5 keV to 11.5 keV at temperatures of 10 K, 50 K, 100 K and 150 K using the hybrid technique are reported. This is the first time transition metal X-ray absorption fine structure (XAFS) has been studied using the hybrid technique and at low temperatures. This is also the first hybrid-like experiment at the Australian Synchrotron. The measured transmission and fluorescence XAFS spectra are compared and benchmarked against each other with detailed systematic analyses. A recent method for modelling self-absorption in fluorescence has been adapted and applied to a solid sample. The XAFS spectra are analysed using eFEFFIT to provide a robust measurement of the evolution of nanostructure, including such properties as net thermal expansion and mean-square relative displacement. This work investigates crystal dynamics, nanostructural evolution and the results of using the Debye and Einstein models to determine atomic positions. Accuracies achieved, when compared with the literature, exceed those achieved by both relative and differential XAFS, and represent a state-of-the-art for future structural investigations. Bond length uncertainties are of the order of 20–40 fm.

Zn dendrite growth and water-related side reactions have been criticized to hinder actual applications of aqueous Zn-ion batteries. To address these issues, a series of Zn interfacial modifications of building solid/electrolyte interphase (SEI) and nucleation layers have been widely proposed, however, their effectiveness remains debatable. Here, we report a boron nitride (BN)/Nafion layer on the Zn surface to efficiently solve Zn problems through combining the hybrid working mechanisms of SEI and nucleation layers. In our protective layer, Nafion exhibits the SEI mechanism by blocking water from the Zn surface and providing abundant channels for rapid Zn2+ transmission, whilst BN nanosheets induce Zn deposition underneath with a preferred (002) orientation. Accordingly, dendrite-free and side-reaction-free Zn electrode with (002) deposition under the protective layer is realized for the first time, as reflected by its high reversibility with average Coulombic efficiency of 99.2% for > 3000 ​h. The protected Zn electrode also shows excellent performance in full cells when coupling with polyaniline cathode under the strict condition of lean electrolyte addition. This work highlights insights for designing highly reversible metal electrodes towards practical applications.

The structural determination of ultrasmall clusters remains a challenge due to difficulties in crystallisation. Often the atomically precise clusters undergo structural change under the influence of the environment. X-ray absorption spectroscopy (XAS) can be an attractive tool to study the electronic and geometric properties of such clusters deposited onto various supports under in situ conditions. Herein, [Au6(dppp)4](NO3)2, [Au9(PPh3)8](NO3)3, [Au13(dppe)5Cl2]Cl3, and Au101(PPPh3)21Cl5 clusters were studied using XAS. The clusters exhibited distinct features compared to bulk gold. XANES results show a systematic increase in the absorption edge energy and white line intensity, with a decrease in cluster nuclearity. The EXAFS of clusters are sensitive to nuclearity and ligands and were fitted with their known crystal structures. This study advances the understanding of the phosphine-ligated metal clusters relevant to practical applications in catalysis and sensing.