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The recent report of room-temperature superconductivity at near-ambient pressure in nitrogen-doped lutetium hydride (Lu-H-N) by Dasenbrock-Gammon et al. [ Nature 615, 244–250 (2023)] has attracted tremendous attention due to its anticipated great impact on technology. However, the results could not be independently reproduced by other groups worldwide in follow-up studies, which elicited intense controversy. Here, we develop a reliable experimental protocol to minimize the extensively concerned extrinsic influences on the sample by starting the reaction from pure lutetium loaded with an H2/N2 gas mixture in a diamond anvil cell under different pressures and temperatures and simultaneously monitoring the entire chemical reaction process using in situ four-probe resistance measurements. Therefore, we could repeatedly reproduce the near-room temperature upsurge of electrical resistance at a relatively early stage of the chemical reaction. However, the mechanism is suggested to be a metal-to-semiconductor/insulator transition associated with the structural modulation in the non-stoichiometric Lu-H-N, rather than superconductivity. [ABSTRACT FROM AUTHOR]

The tailoring of active sites is closely related to the substrate. Dual‐atom catalysts (DACs) have been achieved on doped carbon, oxides, and 2D materials, but are rarely reported on metals, due to the challenges of sintering and alloying using metal as the host. Herein, an innovative approach to anchor isolated single atoms as dual‐atomic‐site alloy (DASA) through two‐step pyrolysis of porous structure is proposed. Firstly, the role of Zn and Co in generating pores during the pyrolysis of zeolite imidazolate framework (ZIFs) is revealed, and a hierarchical porous structure with self‐supported Co particles is achieved by the first‐step pyrolysis. Diffusion‐controlled reduction of precursors containing target metals is then allowed through hierarchical structures by second‐step pyrolysis, so to address the challenge of sintering and alloying at pyrolysis of high temperatures. The approach is demonstrated by synthesizing Ir1Ni1@Co/N‐C DASA, with outstanding bifunctional oxygen reduction/evolution reaction (ORR/OER) performance in both acidic and alkaline media, which is rarely reported. The density functional theory (DFT) calculations represent that adsorption‐free energies of intermediates OH and O are regulated to nearly 0 eV by Ir1 and Ni1 on Co. This work demonstrates a new path of constructing DASA using the designed porous structure, inspiring catalysts design in a related field. [ABSTRACT FROM AUTHOR]

Iridium (Ir) single-atom catalysts (SACs) exhibit extraordinary advantages in the oxygen evolution reaction (OER) owing to their unique electronic structure and maximized atom utilization. However, further developments have met with bottlenecks due to the limited catalytic activity derived from the widely adopted adsorbate evolution mechanism (AEM) pathway in Ir SACs for OER. Herein, we report an efficient strategy to improve the intrinsic activity of Ir SACs by anchoring atomic Ir on an oxygen vacancy-modified CoNiO2 support (IrSA-VO-CoNiO2), in which a more advanced lattice oxygen oxidation (LOM) pathway is constructed by activating lattice oxygen to participate in OER. Specifically, the synthesized CoNiO2 support could provide the weak metal–oxygen bond and facilitate the movement and conversion of lattice oxygen. The oxygen vacancies provided abundant active sites for the adsorption of OH* and induced a substantial O 2p characteristic near the Fermi level for activating the lattice oxygen in CoNiO2. Moreover, the introduction of Ir atoms in the oxygen vacancies modulated CoNiO2 results in the significant overlap between the Ir 5d and O 2p bands and constructed a stronger Ir–O covalent bond, which extremely facilitated the transformation from O–O to OO* for boosting the final O2 evolution. Through the above-mentioned results, a more efficient LOM pathway in the single-atom Ir catalyst was constructed, and the as-synthesized IrSA-VO-CoNiO2 displayed outstanding OER performance with 10 mA cm−2 at a low overpotential of 183 mV and a high mass activity of 5 A mg−1 at the overpotential of 300 mV, significantly outperforming the reported catalysts. This work proposes an advanced channel to design efficient electrocatalysts for promising OER applications. [ABSTRACT FROM AUTHOR]

In this work, a lead-free 0.86(0.93Na1/2Bi1/2TiO3-0.07BaTiO3)-0.14K1/2Bi1/2(Zn1/3Nb2/3)O3 (KBZN14) ergodic relaxor demonstrates excellent energy storage performance: Ws = 6.48 J cm−3, Wr = 5.10 J cm−3, and η = 80% at a moderate field of 29.0 kV mm−1, accompanied by an outstanding frequency and temperature stability as well as a fast discharge rate t0.9 of 69–79 ns. The excellent energy storage performance of the sample KBZN14 originates from the synergic effect of KBZN introduction: the enlargement of the [AO12] cages of the pseudocubic perovskite host to facilitate the local polarization, and the complex cations (Zn1/3Nb2/3)4+ destroy the long-range correlations to percolate the polar nanoregions (PNRs) to room temperature. Our work provides a way to design NBT-based materials as a candidate for high energy density and pulse capacitor applications. [ABSTRACT FROM AUTHOR]

Moiré fringe, originated from the beating of two sets of lattices, is a commonly observed phenomenon in physics, optics, and materials science. Recently, a new method of creating moiré fringe via scanning transmission electron microscopy (STEM) has been developed to image materials' structures at a large field of view. Moreover, this method shows great advantages in studying atomic structures of beam sensitive materials by significantly reduced electron dose. Here, the development of the STEM moiré fringe (STEM‐MF) method is reviewed. The authors first introduce the theory of STEM‐MF and then discuss the advances of this technique in combination with geometric phase analysis, annular bright field imaging, energy dispersive X‐ray spectroscopy, and electron energy loss spectroscopy. Applications of STEM‐MF on strain, defects, 2D materials, and beam‐sensitive materials are further summarized. Finally, the authors′ perspectives on the future directions of STEM‐MF are presented. [ABSTRACT FROM AUTHOR]

WS 2 is an attractive anode in alkali metal ion batteries (AMIBs) due to its 2D-layered structure and high theoretical capacity. However, the shuttle effect of sulfur and the spontaneous growth of W nanoparticles are key issues that limit the alkali-ion accommodation ability. Now, it is still a great challenge to achieve in situ control of the microstructure evolution paths in enclosed batteries for extending the cycling reversibility/lifespan. Herein, the phase conversion paths of both film- and powder-type WS 2 anodes are investigated in lithium-ion batteries. It is found that the reversible conversion mechanism is beneficial for alleviating the shuttle effect through strong W-Li x S y bonding. Also, once the size of the phase-converted W/WS 2 redox pair exceeds ∼10 nm inside the anode layer, the Li + storage ability will severely decay due to uncontrollable W precipitation. To maintain high reversibility, amorphous Al 2 O 3 is introduced upon pristine WS 2 . After initializing the battery test, the particle size of the W/WS 2 redox pair is in situ modulated within the range of ∼3-5 nm because of the refinement effect of gradually pulverized Al 2 O 3 . Thus, the decay suppression effect lasting over 750-1400 cycles is obtained with enhanced W ↔ WS 2 conversion efficiency and good capacity retention. This is expected to promote the optimization of Mo-group sulfides/selenides/tellurides toward AMIBs.

Alloying has significantly upgraded the oxygen reduction reaction (ORR) of Pd-based catalysts through regulating the thermodynamics of oxygenated intermediates. However, the unsatisfactory activation ability of Pd-based alloys toward O 2 molecules limits further improvement of ORR kinetics. Herein, the precise synthesis of nanosheet assemblies of spin-polarized PdCu-Fe 3 O 4 in-plane heterostructures for drastically activating O 2 molecules and boosting ORR kinetics is reported. It is demonstrated that the deliberate-engineered in-plane heterostructures not only tailor the d-band center of Pd sites with weakened adsorption of oxygenated intermediates but also endow electrophilic Fe sites with strong ability to activate O 2 molecules, which make PdCu-Fe 3 O 4 in-plane heterostructures exhibit the highest ORR specific activity among the state-of-art Pd-based catalysts so far. In situ electrochemical spectroscopy and theoretical investigations reveal a tandem catalytic mechanism on PdCu-Fe 3 O 4 ─Fe sites that initially activate molecular O 2 and generate oxygenated intermediates being transferred to Pd sites to finish the subsequent proton-coupled electron transfer steps., (© 2024 Wiley‐VCH GmbH.)

Electrocatalytic CO 2 reduction (eCO 2 R) in acid holds promise in renewable electricity-powered CO 2 utilization with high efficiency, but the hydrogen evolution reaction (HER) often prevails and results in a low eCO 2 R selectivity. Here, using cobalt phthalocyanine/Ketjen black (CoPc/KB) as the model catalysts, we systematically study the effect of active site density, operational current density, and hydrated cations on the acidic eCO 2 R selectivity and decipher it through the componential dynamics of electric double layer (EDL). The optimal CoPc-4/KB demonstrates a near-unity CO Faradaic efficiency from 50 to 400 mA cm -2 and superb operational stability (>120 h) at 100 mA cm -2 . Aided by in situ Raman and infrared spectroscopies, we reveal that the proper cations establish an electrostatic shield for mitigating bulk H + penetration and mediate the interfacial water structure for suppressing HER. This study should elicit further profound thinking on robust eCO 2 R system design from the perspective of multiphasic and dynamic EDL.

Density functional theory (DFT) calculations demonstrate neighboring Pt atoms can enhance the metal activity of NiCoP for hydrogen evolution reaction (HER). However, it remains a great challenge to link Pt and NiCoP. Herein, we introduced curvature of bowl-like structure to construct Pt/NiCoP interface by adding a minimal 1 ‰-molar-ratio Pt. The as-prepared sample only requires an overpotential of 26.5 and 181.6 mV to accordingly achieve the current density of 10 and 500 mA cm -2 in 1 M KOH. The water dissociation energy barrier (E a ) has a ~43 % decrease compared with NiCoP counterpart. It also shows an ultrahigh stability with a small degradation rate of 10.6 μV h -1 at harsh conditions (500 mA cm -2 and 50 °C) after 3000 hrs. X-ray photoelectron spectroscopy (XPS), soft X-ray absorption spectroscopy (sXAS), and X-ray absorption fine structure (XAFS) verify the interface electron transfer lowers the valence state of Co/Ni and activates them. DFT calculations also confirm the catalytic transition step of NiCoP can change from Heyrovsky (2.71 eV) to Tafel step (0.51 eV) in the neighborhood of Pt, in accord with the result of the improved H ads at the interface disclosed by in situ electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) tests., (© 2024 Wiley-VCH GmbH.)

The recent report of room-temperature superconductivity at near-ambient pressure in nitrogen-doped lutetium hydride (Lu-H-N) by Dasenbrock-Gammon et al. [ Nature 615, 244-250 (2023)] has attracted tremendous attention due to its anticipated great impact on technology. However, the results could not be independently reproduced by other groups worldwide in follow-up studies, which elicited intense controversy. Here, we develop a reliable experimental protocol to minimize the extensively concerned extrinsic influences on the sample by starting the reaction from pure lutetium loaded with an H 2 /N 2 gas mixture in a diamond anvil cell under different pressures and temperatures and simultaneously monitoring the entire chemical reaction process using in situ four-probe resistance measurements. Therefore, we could repeatedly reproduce the near-room temperature upsurge of electrical resistance at a relatively early stage of the chemical reaction. However, the mechanism is suggested to be a metal-to-semiconductor/insulator transition associated with the structural modulation in the non-stoichiometric Lu-H-N, rather than superconductivity., (© The Author(s) 2023. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.)

The Co-N 4 -C single-atom catalysts (SACs) have attracted great research interest in the energy storage and conversion fields owing to 100% atom utilization. However, enhancing the Co loading for higher electrocatalytic performance is still challenging. In this context, we propose an engineering strategy to fabricate the high Co atomic loading Co-N 4 -C SACs based on the zeolitic imidazolate framework-67 (ZIF-67)@yeast construction. The rich amino groups provide the possibility for Co 2+ ion anchorage and ZIF-67@yeast construction via the biomineralization of yeast cells. The functional design induces the formation of Co-N 4 -C sites and regulates the porosity for exposure of such Co-N 4 -C sites. As a result, the Co-N 4 -C sites were anchored on spherical micrometer flower carbonaceous materials through our novel strategy. The as-obtained optimal sample exhibited a Co atomic loading of 12.18 wt % and a specific surface area of 403.26 m 2 g -1 . High Co atomic loading and large specific surface area delivered excellent electrocatalytic kinetics as well as a high discharge voltage of 1.08 V at 10 mA cm -2 for more than 100 h in Zn-air batteries. This work represents a promising strategy for fabricating high-loading SACs with high activity and good durability.