Water electrolysis shows great promise for the low-cost mass production of high-purity hydrogen. The relatively high dissociation energy of water, however, often results in rather sluggish kinetics ...of the hydrogen evolution reaction (HER) in alkaline conditions, even for the case of state-of-the-art Pt-based electrocatalysts. Here, we show the high efficiency of the hybrids of PtRu nanoclusters (NCs) and black phosphorus (BP) nanosheets in HER. Our PtRu NCs/BP electrocatalysts demonstrate a HER activity of 88.5 mA cm–2 at −70 mV in 1 M KOH, which is higher than that of commercial Pt/C by 1 order of magnitude. The observed extraordinarily high HER activity of the PtRu NCs/BP hybrids is interpreted in the framework of density functional theory. Theoretical modeling indicates that the electronic interaction between BP and PtRu NCs speeds up the dissociation of water and optimizes the adsorption strength for H* species, giving rise to the remarkably high HER activity of the PtRu NCs/BP hybrids.
Crystalline and amorphous structures are two of the most common solid‐state phases. Crystals having orientational and periodic translation symmetries are usually both short‐range and long‐range ...ordered, while amorphous materials have no long‐range order. Short‐range ordered but long‐range disordered materials are generally categorized into amorphous phases. In contrast to the extensively studied crystalline and amorphous phases, the combination of short‐range disordered and long‐range ordered structures at the atomic level is extremely rare and so far has only been reported for solvated fullerenes under compression. Here, a report on the creation and investigation of a superconducting quasi‐1D material with long‐range ordered amorphous building blocks is presented. Using a diamond anvil cell, monocrystalline (TaSe4)2I is compressed and a system is created where the TaSe4 atomic chains are in amorphous state without breaking the orientational and periodic translation symmetries of the chain lattice. Strikingly, along with the amorphization of the atomic chains, the insulating (TaSe4)2I becomes a superconductor. The data provide critical insight into a new phase of solid‐state materials. The findings demonstrate a first ever case where superconductivity is hosted by a lattice with periodic but amorphous constituent atomic chains.
Combination of long‐range ordered and short‐range disordered structures at the atomic level is demonstrated for a quasi‐1D linear chain compound. Under compression, the constituent atomic chains of the material are amorphized without breaking the orientational and periodic translation symmetries of the chain lattice. This lattice of amorphous atomic chains hosts a quantum condensate of Cooper pairs.
The emergence of superconductivity in doped insulators such as cuprates and pnictides coincides with their doping‐driven insulator–metal transitions. Above the critical doping threshold, a metallic ...state sets in at high temperatures, while superconductivity sets in at low temperatures. An unanswered question is whether the formation of Cooper pairsin a well‐established metal will inevitably transform the host material into a superconductor, as manifested by a resistance drop. Here, this question is addressed by investigating the electrical transport in nanoscale rings (full loops) and half loops manufactured from heavily boron‐doped diamond. It is shown that in contrast to the diamond half‐loops (DHLs) exhibiting a metal–superconductor transition, the diamond nanorings (DNRs) demonstrate a sharp resistance increase up to 430% and a giant negative “magnetoresistance” below the superconducting transition temperature of the starting material. The finding of the unconventional giant negative “magnetoresistance”, as distinct from existing categories of magnetoresistance, that is, the conventional giant magnetoresistance in magnetic multilayers, the colossal magnetoresistance in perovskites, and the geometric magnetoresistance in semiconductor–metal hybrids, reveals the transformation of the DNRs from metals to bosonic semiconductors upon the formation of Cooper pairs. DNRs like these could be used to manipulate Cooper pairs in superconducting quantum devices.
Nanoscale “diamond rings” provide unconventional giant “magnetoresistance” for the development of new quantum devices. The unconventional giant “magnetoresistance” caused by the trapping of Cooper pairs within the heavily boron‐doped diamond nanorings, distinguishes itself from the conventional giant magnetoresistance originating from spin‐dependent scattering of single electrons in layered magnetic materials.
Superconducting nanowires currently attract great interest due to their application in single-photon detectors and quantum-computing circuits. In this context, it is of fundamental importance to ...understand the detrimental fluctuations of the superconducting order parameter as the wire width shrinks. In this paper, we use controlled electromigration to narrow down aluminium nanoconstrictions. We demonstrate that a transition from thermally assisted phase slips to quantum phase slips takes place when the cross section becomes less than ∼150 nm(2). In the regime dominated by quantum phase slips the nanowire loses its capacity to carry current without dissipation, even at the lowest possible temperature. We also show that the constrictions exhibit a negative magnetoresistance at low-magnetic fields, which can be attributed to the suppression of superconductivity in the contact leads. These findings reveal perspectives of the proposed fabrication method for exploring various fascinating superconducting phenomena in atomic-size contacts.
Three-dimensional (3D) printing, as an advanced additive manufacturing technique, is emerging as a promising material-processing approach in the electrical energy storage and conversion field, e.g., ...electrocatalysis, secondary batteries and supercapacitors. Compared to traditional manufacturing techniques, 3D printing allows for more the precise control of electrochemical energy storage behaviors in delicately printed structures and reasonably designed porosity. Through 3D printing, it is possible to deeply analyze charge migration and catalytic behavior in electrocatalysis, enhance the energy density, cycle stability and safety of battery components, and revolutionize the way we design high-performance supercapacitors. Over the past few years, a significant amount of work has been completed on 3D printing to explore various high-performance energy-related materials. Although impressive strides have been made, challenges still exist and need to be overcome in order to meet the ever-increasing demand. In this review, the recent research progress and applications of 3D-printed electrocatalysis materials, battery components and supercapacitors are systematically presented. Perspectives on the prospects for this exciting field are also proposed with applicable discussion and analysis.
In the presence of disorder, superconductivity exhibits short-range characteristics linked to localized Cooper pairs which are responsible for anomalous phase transitions and the emergence of quantum ...states such as the bosonic insulating state. Complementary to well-studied homogeneously disordered superconductors, superconductor-normal hybrid arrays provide tunable realizations of the degree of granular disorder for studying anomalous quantum phase transitions. Here, we investigate the superconductor–bosonic dirty metal transition in disordered nanodiamond arrays as a function of the dispersion of intergrain spacing, which ranges from angstroms to micrometers. By monitoring the evolved superconducting gaps and diminished coherence peaks in the single-quasiparticle density of states, we link the destruction of the superconducting state and the emergence of bosonic dirty metallic state to breaking of the global phase coherence and persistence of the localized Cooper pairs. The observed resistive bosonic phase transitions are well modeled using a series–parallel circuit in the framework of bosonic confinement and coherence.
The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity ...substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm(2) cross-section. The impurities suppress superconductivity in a three-dimensional 'Swiss cheese'-like pattern with in-plane and out-of-plane characteristic lengths slightly below ∼1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities.
The combination of different exotic properties in materials paves the way for the emergence of their new potential applications. An example is the recently found coexistence of the mutually ...antagonistic ferromagnetism and superconductivity in hydrogenated boron-doped diamond, which promises to be an attractive system with which to explore unconventional physics. Here, we show the emergence of Yu-Shiba-Rusinov (YSR) bands with a spatial extent of tens of nanometers in ferromagnetic superconducting diamond using scanning tunneling spectroscopy. We demonstrate theoretically how a two-dimensional (2D) spin lattice at the surface of a three-dimensional (3D) superconductor gives rise to the YSR bands and how their density-of-states profile correlates with the spin lattice structure. The established strategy to realize new forms of the coexistence of ferromagnetism and superconductivity opens a way to engineer the unusual electronic states and also to design better-performing superconducting devices.
As an extension of single-atom catalysts, despite the increased opportunities to optimize the hydrogen evolution reaction (HER) activity with the variation of the composition, dual-metal-atom ...catalysts, i.e., dimers, are deeply trapped in a design blind spot due to the lack of the essential recognition of the intrinsic catalytic mechanism at the atomic level. Herein, based on first-principles calculations, a series of platinum–transition metal dimers were constructed on nitrogen-doped graphene (PtM–NDG, M = Fe, Co, Ni, Cu) to reveal the effects of the internal (i.e., M atom) and external (i.e., NDG substrate) environments on the HER activity. Computational results show that the original over-adsorption of hydrogen intermediate (H*) of PtM dimer is weakened after the introduction of NDG, and the optimal active site migrates from the Pt in PtM dimer to the Pt–M bridge in PtM–NDG, triggered by the redistribution of the charge density of the metal atoms. In particular, the M atom switches from tuning the d-band center of the Pt atom to indirectly assist the adsorption behavior of Pt in the PtM dimer to the direct participation in the bonding with H* in PtM–NDG via its own d-band to regulate the distribution of σ and σ*, which enables fine modulation of the bond strength with H*. Moreover, the overall hydrogen evolution performance of PtM–NDG is mainly determined by the d-band center of the M atom. Furthermore, PtFe–NDG with the lowest energy barrier of the rate-determining step stands out in the process of H2 desorption and water dissociation. The present work deepens our understanding of the effects of the metal dopant and substrate on the catalytic performance of platinum.
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