摘要：High-entropy alloys(HEAs)have been widely studied due to their unconventional compositions and unique physicochemical properties for various ***,for the first time,we propose a surface strain strategy to tune the electrocatalytic activity of HEAs for methanol oxidation reaction(MOR).High-resolution aberration-corrected scanning transmission electron microscopy(STEM)and elemental mapping demonstrate both uniform atomic dispersion and the formation of a face-centered cubic(FCC)crystalline structure in Pt Fe Co Ni Cu *** HEAs obtained by heat treatment at 700℃(HEA-700)exhibit 0.94%compressive strain compared with that obtained at 400℃(HEA-400).As expected,the specific activity and mass activity of HEA-700 is higher than that of HEA-400 and most of the state-of-the-art *** enhanced MOR activity can be attributed to a shorter Pt–Pt bond distance in HEA-700 resulting from compressive *** nonprecious metal atoms in the core could generate compressive strain and down shift d-band centers via electron transfer to surface Pt *** work presents a new perspective for the design of high-performance HEAs electrocatalysts.

摘要：Alloying Pt with transition metals can significantly improve the catalytic properties for the oxygen reduction reaction(ORR).However,the application of Pt-transition metal alloys in fuel cells is largely limited by poor long-term durability because transition metals can easily *** this study,we developed a nonmetallic doping approach and prepared a P-doped Pt catalyst with excellent durability for the ***-supported core-shell nanoparticles with a P-doped Pt core and Pt shell(denoted as PtPx@Pt/C)were synthesized via heat-treatment phosphorization of commercial Pt/C,followed by acid *** analysis using electron energy loss spectroscopy and X-ray photoelectron spectroscopy clearly demonstrated that Pt was enriched in the near-surface region(approximately 1 nm)of the carbon-supported core-shell *** to P doping,the ORR specific activity and mass activity of the PtP_(1.4)@Pt/C catalyst were as high as 0.62 mA cm^(–2)and 0.31 mAμgPt–^(1),respectively,at 0.90 V,and they were enhanced by 2.8 and 2.1 times,respectively,in comparison with the Pt/C *** importantly,PtP_(1.4)@Pt/C exhibited superior stability with negligible mass activity loss(6%after 30000 potential cycles and 25%after 90000 potential cycles),while Pt/C lost 46%mass activity after 30000 potential *** high ORR activity and durability were mainly attributed to the core-shell nanostructure,the electronic structure effect,and the resistance of Pt nanoparticles against aggregation,which originated from the enhanced ability of the PtP_(1.4)@Pt to anchor to the carbon *** study provides a new approach for constructing nonmetal-doped Pt-based catalysts with excellent activity and durability for the ORR.

摘要：水系可充电锌/二氧化锰电池因其成本低廉、能量密度高而引起了广泛关注.然而,缓慢的反应动力学和MnO_(2)阴极的歧化反应以及不可逆的相变现象对其发展造成了严重阻碍.在此,我们选用了Mo掺杂α-MnO_(2)(Mo–MnO_(2))作为阴极材料,通过铵根离子插层机制所形成的N–H···O强键合作用来稳定Mo–MnO_(2)的2×2隧道结构,并且有效抑制了Mn^(3+)溶解,在质子插入/脱出过程中不会引起晶格的畸变,进一步提高了其循环稳定性.获得的Mo–MnO_(2)正极在100 mA g^(−1)时表现出265.2 mA h g^(−1)的高比容量和364.3 W h kg^(−1)的能量密度.在2.0 A g^(−1)下1000次循环后,容量保持率达95.2%.这项工作有助于深入了解非金属阳离子在电极主体材料间的键合作用,为设计具有高能量密度和长期循环能力的水系锌离子电池提供了新思路.

摘要：Sodium metal anode holds great promise in pursuing high-energy and sustainable rechargeable batteries,but severely suffers from fatal dendrite growth accompanied with huge volume ***,a robust mixed conducting sodium metal anode is designed through incorporating Na SICON-type solid Na-ion conductor into bulk Na.A fast and continuous pathway for simultaneous transportation of electrons and Na+is established throughout the composite *** intimate contact between Na-ion conducting phase and Na metallic phase constructs abundant two-phase boundaries for fast redox ***,the compact configuration of the composite anode substantially protects Na metal from being corroded by liquid organic electrolyte for the minimization of side *** from the unique configuration,the composite anode shows highly reversible and durable Na plating/stripping *** symmetric cells exhibit ultralong lifespan for over 700 h at 1 mA cm^(-2)with a high capacity of 5 m Ah cm^(-2)and outstanding rate capability up to 8 m A cm^(-2)in the carbonate *** cells with Na_(3)V_(2)(PO_(4))_(3)/C cathode demonstrate impressive cycling stability(capacity decay of 0.012%per cycle)and low charge/discharge polarization as *** work provides new insights into rational design and development of robust sodium metal anode through an architecture engineering strategy for advanced rechargeable sodium batteries.

摘要：Noble metals are downsized to nano-/subnanoscale to improve their catalytic activity and ***,the stabilities in chemical state and catalytic performance of these nanocatalysts often suffer during harsh *** Pt nanoparticles(NPs)supported on CeO2,activated oxygen diffused from the support over-stabilizes the active sites of Pt,degrading its performance at mild *** this work,Pt nanocatalysts with unique structure of triple-junction are synthesized by selectively growing Pt NPs on the carbon-CeO2 ***,the Pt NPs exhibit much enhanced catalytic stability and high activity for CO oxidation at mild *** enhancement is attributed to electron donation from graphitized carbon and the confinement effect from the high-density nanopores of the CeO2 *** triple-junction of Pt-C-CeO2,combining the merits of CeO2 for activating O2 and electron donating capability of carbon,provides new inspiration to the fabrication of high-performance nanocatalysts.

摘要：Common solar-driven photoelectrochemical(PEC) cells for water splitting were designed by using semiconducting photoactive materials as working photoelectrodes to capture sunlight. Due to the thermodynamic requirement of 1.23 eV and kinetic energy loss of about 0.6 eV, a photo-voltage of 1.8 V produced by PEC cells is generally required for spontaneous water splitting. Therefore, the minimum bandgap of1.8 eV is demanded for photoactive materials in single-photoelectrode PEC cells, and the bandgap of about 1 eV for back photoactive materials is appropriate in tandem PEC cells. All these PEC cells cannot effectively utilize the infrared light from 1250 to 2500 nm. In order to realize the full spectrum utilization of solar light, here, we develop a solar-driven PEC water splitting system integrated with a thermoelectric device. The key feature of this system is that the thermoelectric device produces a voltage as an additional bias for the PEC system by using the temperature difference between the incident infrared-light heated aqueous electrolyte in the PEC cell as the hot source and unirradiated external water as the cold source. Compared to a reference PEC system without the thermoelectric device, this system has a significantly improved overall water splitting activity of 1.6 times and may provide a strategy for accelerating the application of full spectrum solar light-driven PEC cells for hydrogen production.

摘要：Developing efficient electrocatalysts for the oxygen evolution reaction(OER)under neutral conditions is important for microbial electrolysis cells(MECs).However,the OER kinetics in neutral electrolytes at present are extremely sluggish,resulting in high overpotentials that greatly limit the energy conversion efficiencies of *** studies failed to probe the adsorbates on surface metal sites of catalysts at the atomic scale and elucidate their influence on the catalytic activities,which has impeded the rational design of efficient neutral OER catalysts with optimal surface ***,using in situ transmission electron microscopy(TEM),in situ X-ray photoelectron spectroscopy(XPS)and in situ low-energy ion scattering studies,we have identified,for the first time,that the electrochemically activated adsorbates on surface metal sites play a critical role in boosting the neutral OER activities of Ru-Ir binary oxide(RuxIryO2)*** adsorbate-activated RuxIryO2on a glassy carbon electrode achieved a low overpotential of 324 m V at10 m A cm-2in neutral electrolyte,with a 36-fold improvement in turnover frequency compared with that of Ir *** application in an MEC system,the resulting full cell showed a decreased voltage of 1.8 V,200 m V lower than the best value reported to date,facilitating efficient synthesis of poly(3-hydroxybutyrate)from bioelectrochemical *** functional theory(DFT)studies revealed that the enhanced OER activity of RuxIryO2catalyst arose from local structural distortion of adjacent adsorbate-covered Ru octahedra at the catalyst surface and the consequently decreased adsorption energies of OER intermediates on Ir active center.

摘要：理解铁电材料畴结构在低温条件下的翻转行为,对于铁电物理以及其在宽温域的应用都非常重要;然而,目前在低温条件下直接观测介观尺度下的畴翻转仍然面临着巨大的挑战.本论文利用铁酸铋(BiFeO_(3))作为模型来研究3.6–260 K温度范围内的铁电畴翻转行为.菱形相的BiFeO_(3)在温度为130 K时观测到了明显的铁电保持失效现象;这是因为BiFeO_(3)在130 K附近有较大的热释电系数,从而使其升温到该温度附近时释放了大量的热释电电荷,进而产生较强的退极化场,导致铁电极化翻转.另外,本论文还发现通过纳米尺度设计相界可以有效地抑制铁电保持失效.本研究为变温条件下,尤其是低温温域,研究铁电翻转提供了实验范式.

摘要：With the rapid development of portable devices and internet of things,the requirement of system wearability and integration accelerates the investigation of flexible multifunctional *** this study,we developed an integrated flexible sensing system with four nanowire-based sensors and a Ni microwire-based temperature *** four nanowirebased sensors are three kinds of photodetectors responding to lights with different wavelengths and a gas *** to the large surface volume ratio and considerable sub wavelength effect,all the nanowire-based sensors show good sensing response and excellent linear relationship between sensitivity and *** as-fabricated flexible sensing system can simultaneously detect environmental parameters,including temperature change,light intensities from UV-Visible to near infrared regions,and harmful gas *** flexible multifunctional sensing system therefore opens up a new way for the emerging portable and wearable electronics.

摘要：Synchrotron radiation-based micro-Laue technique has showcased great application potentials in materials science study for its unprecedented crystal orientation and lattice strain/stress *** we report the updated progress in the development of the micro-Laue technique on the X-ray test beamline at Shanghai Synchrotron Radiation *** far,40μm(h)×50μm(v)X-ray beam spot is routinely obtained,with the convergent angle of 0.2 mrad(h)×0.12 mrad(v).Area scans are conducted on a GH3535 Nibased superalloy base metal and weld joint with the same chemical *** analyzing the tremendous amount of Laue diffraction patterns using in-house developed software packages,the crystal orientation,elastic strain,and defect distributions are mapped and *** a successful proof-of-principle study offers first-hand experience on the further optimization of the design and construction of the scanning micro-Laue facility on the superbend beamline with improved spatial resolution and multiple functions for simultaneous chemical fluorescence mapping and in-situ microstructural evolution *** micro-Laue diffraction beamline at Shanghai Synchrotron Radiation Facility will provide a versatile and powerful tool for the orientation and strain/stress mapping combined with phase identification with micron-sized spatial resolution.