The exploration of efficient nonprecious metal eletrocatalysis of the hydrogen evolution reaction (HER) is an extraordinary challenge for future applications in sustainable energy conversion. The family of first-row-transition-metal dichalcogenides has received a small amount of research, including the active site and dynamics, relative to their extraordinary potential. In response, we developed a strategy to achieve synergistically active sites and dynamic regulation in first-row-transition-metal dichalcogenides by the heterogeneous spin states incorporated in this work. Specifically, taking the metallic Mn-doped pyrite CoSe2 as a self-adaptived, subtle atomic arrangement distortion to provide additional active edge sites for HER will occur in the CoSe2 atomic layers with Mn incorporated into the primitive lattice, which is visually verified by HRTEM. Synergistically, the density functional theory simulation results reveal that the Mn incorporation lowers the kinetic energy barrier by promoting H-H bond formation on two adjacently adsorbed H atoms, benefiting H2 gas evolution. As a result, the Mn-doped CoSe2 ultrathin nanosheets possess useful HER properties with a low overpotential of 174 mV, an unexpectedly small Tafel slope of 36 mV/dec, and a larger exchange current density of 68.3 μA cm(-2). Moreover, the original concept of coordinated regulation presented in this work can broaden horizons and provide new dimensions in the design of newly highly efficient catalysts for hydrogen evolution.

rate (≈12 cm 2 V −1 s −1 ) compared to TiO 2 (0.5 cm 2 V −1 s −1 ), a robust hole migration length (≈150 nm) relative to Fe 2 O 3 (2-4 nm), and attractive photostability. [10][11][12][13][14] Nonetheless, the photon-generated holes of the virgin WO 3 photoanode usually suffer from a sequence of inevitable obstruction during overall oxygen-evolving photoanode reaction process including the generation, migration, and reaction, bringing about the unsatisfying water oxidation efficiency. In this regard, with an aim to further breakthroughs for pursuing excellent energy conversion performance in high-potential WO 3 photoanode, integrated dismantling aforesaid restricting factors are greatly imperative.As such, tailoring crystal facets is a conventional strategy for optimizing the catalytic performance in the case of various semiconductor materials because heterogeneous reactivity depends strongly on the surface atomic configuration and bonding environment that can be altered by controlling crystalline facets. [15][16][17][18][19] Considering the specific WO 3 , recent studies have revealed that nanosheets exposed with {001} facets show better catalytic activity than the other facets due to the highest oxygen atom density. [20] Enlightened by atomically thin graphene-like sheets, the ultrathin sheet configuration provides ideal building blocks/architectures for realizing almost fully exposed highactivity lattice plane, as displayed in Scheme 1. [15] And not only that, the ultrathin sheet configuration will attach gratifying idiosyncrasy including fast interfacial charge transfer, 2D conduction channels, and increasing carrier transport for facilitating photoelectrocatalysis performance. [21][22][23][24] Unfortunately, the longish migratory route of holes along the W-O-W chains in the x direction in the {001} facets exposed WO 3 nanosheet will ineluctably suffer from a good deal of electron-hole recombination, as a consequence, tremendously impairing the photoelectrocatalysis nature. [10] In order to resolve the contradictions, artificially manufacture pore structure on the ultrathin nanosheets surface will effectually shorten photon-generated holes diffusion pathway and benefit oxidization of water into O 2 on the WO 3 surface. And beyond that, the abundant unsatisfied chemical bond surrounding the pore provides an excellent chemical environment for promoting chemisorptions of reaction molecular, and then, promotes the catalytic reaction kinetics. [25][26][27] Rational design of active artificial photoanode for photosynthesis water splitting is spotlight for future applications in sustainable energy conversion. In response, focusing on the full-scale restricting factors on the photoanode reaction, the pore-rich WO 3 ultrathin nanosheets with nearly fully exposed highly active crystal facets are conceptually presented and experimentally achieved. The scrumptious chemical bond condition and derived electronic structure in pore-rich nanosheets realize the simultaneously optimizing on the multilimitation factors including ...

Fabricating a flexible room-temperature ferromagnetic resistive-switching random access memory (RRAM) device is of fundamental importance to integrate nonvolatile memory and spintronics both in theory and practice for modern information technology and has the potential to bring about revolutionary new foldable information-storage devices. Here, we show that a relatively low operating voltage (+1.4 V/-1.5 V, the corresponding electric field is around 20,000 V/cm) drives the dual vacancies evolution in ultrathin SnO2 nanosheets at room temperature, which causes the reversible transition between semiconductor and half-metal, accompanyied by an abrupt conductivity change up to 10(3) times, exhibiting room-temperature ferromagnetism in two resistance states. Positron annihilation spectroscopy and electron spin resonance results show that the Sn/O dual vacancies in the ultrathin SnO2 nanosheets evolve to isolated Sn vacancy under electric field, accounting for the switching behavior of SnO2 ultrathin nanosheets; on the other hand, the different defect types correspond to different conduction natures, realizing the transition between semiconductor and half-metal. Our result represents a crucial step to create new a information-storage device realizing the reversible transition between semiconductor and half-metal with flexibility and room-temperature ferromagnetism at low energy consumption. The as-obtained half-metal in the low-resistance state broadens the application of the device in spintronics and the semiconductor to half-metal transition on the basis of defects evolution and also opens up a new avenue for exploring random access memory mechanisms and finding new half-metals for spintronics.

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High pressure electric transport and synchrotron x-ray diffraction (XRD) measurements together with the first-principles calculations are performed on a shandite compound Pd3Pb2Se2 which contains the Kagome lattice of the transition metal Pd. A pressure-induced superconducting transition is observed above 25 GPa, for the first time in the shandite compounds, although the crystal structure of the compound seems to be very robust and persists up to the highest pressure in the XRD study (76.3 GPa). The superconducting transition temperature is about 2.2 K and almost does not change with pressure. The carrier density suddenly increases around 20 GPa possibly due to the emergence of two electron pockets at the Γ point. Our work indicates that the superconductivity in Pd3Pb2Se2 is strongly correlated to its electronic structure.

The irradiation-induced sputtering and the structural damage at tungsten surface are investigated by using molecular dynamics simulations at the level of quantum mechanics. Our simulations indicate that the sputtered atoms appear when the energy of incident primary knock-on atom (PKA) is more than 200 eV and the incident angle of the PKA is larger than 65 •. Meanwhile, the irradiation-induced vacancies are less when the incident angle of PKA is in the range of 45 • −65 •. So, the optimum incident angles of PKA are suggested to reduce the irradiation-induced damage of the W surface. Furthermore, we find that the interstitials contained in the systems accelerate the sputtering whereas the intrinsic vacancies suppress the sputtering when the PKA is near the defects.