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Constructing highly active electrocatalysts for hydrogen evolution reaction (HER) have drawn considerable attention recently. However, how to design nanostructured electrocatalysts with enhanced catalytic performances is still a challenge. Herein, plasmonic Ag/Au hollow porous nanoshells decorated with porous Fe 2 P thin layers (denoted as Ag/Au-HPNSs@PFP) are fabricated, in which porous Fe 2 P (PFP) thin layers are derived from pyrolysis and phosphidation of MIL-100(Fe) coated on plasmonic Ag/Au hollow porous nanoshells (Ag/Au-HPNSs) and the high porosity of the HER-active Fe 2 P, along with plasmonic enhancement of the Ag/Au hollow porous nanoshells, facilitates hydrogen evolution and electron transport, and accordingly boosts the electrocatalytic HER performance. When applied as a HER electrode, the hybrid electrocatalyst displays an onset overpotential of only 108 mV, satisfactory stability, and enhanced performance for hydrogen evolution under visible light, ascribing to electron interactions between Fe and P and synergistic effects of porous Fe 2 P and plasmonic Au/Ag hollow porous nanoshells. • Plasmonic hybrid electrocatalysts with enhanced HER are successfully fabricated. • Intriguing performance is due to the synergistic effects and plasmonic enhancement. • Promoted HER performance and satisfactory stability are demonstrated. [ABSTRACT FROM AUTHOR]

3D HPN-GCNS/Co@CoO x as catalysts for ORR: The hybrids were fabricated by a controllable grading-pyrolysis strategy. The hybrids show 3D fluffy and hierarchically porous nanostructure in and out-of-plane, resulting in large accessible specific activity area, allowing the species to efficiently participate in ORR and facilitating the fast mass transfer; the graphene-like C nanosheets with N-rich dopant promote O 2 adsorption and assure fast electron transport; large numbers of Co@CoO x -based nanoparticles uniformly embedded on the C nanosheets and mesoporous active edge introduce more ORR active sites. The remarkable features synergistically enhance the ORR catalytic efficiency, making it a promising low-cost, highly efficient ORR catalyst. • The hybrids were successfully fabricated by a controllable grading pyrolysis strategy. • Graphene-like C nanosheets with N-rich dopant show in and out-of-plane nanostructure. • Co-based nanoparticles uniformly embedded on fluffy and hierarchically C nanosheets. • The remarkable features synergistically enhance the ORR catalytic efficiency. Here, Co@CoO x -based three-dimensional nitrogen-doped graphene-like carbon nanosheets (denoted as 3D HPN-GCNS/Co@CoO x) are fabricated by controllable grading-pyrolysis strategy, in which they show 3D fluffy and hierarchically porous nanostructure in and out-of-plane; large numbers of Co@CoO x -based nanoparticles uniformly embedded on graphene-like C nanosheets and mesoporous active edge introduce more ORR active sites. When applied for ORR, hybrids exhibit a half-wave potential (E 1/2) of 0.87 V and an onset potential (E onset) of 0.92 V in 0.1 M KOH, comparable to that of commercial 20% Pt/C. The hybrids display better methanol tolerance and stability, with almost no change of ORR performance before and after 5000 cycles. H 2 O 2 yield in ORR process is less than 5% and number of electron transfer is higher than 3.9. The remarkable features are mainly ascribed to synergistic enhancement effect, in which 3D fluffy and hierarchically porous nanostructure in and out-of-plane supplies large accessible specific activity area, allows species to efficiently participate in ORR and facilitates fast mass transfer; graphene-like C nanosheets with N-rich dopant promote O 2 adsorption and assure fast electron transport; large numbers of Co@CoO x -based nanoparticles introduce more ORR active sites. All the advantages synergistically enhance the ORR efficiency and make it a highly efficient ORR catalyst. [ABSTRACT FROM AUTHOR]

Abstract In order to construct the molybdenum disulfide (MoS 2) hybrid nanostructure with enhanced conductivity and more active sites towards electrocatalytic hydrogen evolution reaction (HER), hierarchical P-doped MoS 2 nanopetals decorated N-doped hollow carbon spheres (N-C@P-MoS 2) core-shell structures were synthesized via calcination and hydrothermal methods. N-C@P-MoS 2 with optimized loadings exhibited favorable HER activities with low onset overpotential (117 mV), small Tafel slopes (68 mV/dec), and fine stability compared with pure MoS 2 nanosheets and all undoped samples. This is largely ascribed to the synergy of MoS 2 and carbon in the rational hierarchical structures, as well as the modified electronic structure with improved conductivity, increased active sites by virtue of N and P doping. Furthermore, P-doped MoS 2 nanosheets were encapsulated in carbon spheres (N-C/P-MoS 2 (inside)) by controlling the dropping rate of adding MoS 2 precursors. As the active sites were hampered, the N-C/P-MoS 2 (inside) revealed poor HER performance compared with the core-shell counterparts. The results demonstrate that the fabrication of hierarchical MoS 2 /carbon composites with the synergy of structural (morphology and content) and electronic (active sites and conductivity) effects induced by various nonmetal doping pave the way for enhanced electrocatalytic HER activities. Graphical abstract The P-doped MoS 2 nanopetals decorated hollow N-doped carbon spheres core-shell structures (N-C@P-MoS 2) were synthesized successfully via hydrothermal method. Due to the synergy of modified electronic effect and controllable structural effect, the N-C@P-MoS 2 exhibited desirable property in electrocatalytic hydrogen production, compared with other undoped and inside structures. Image 1 Highlights • The P-MoS 2 decorated on and in N-CS were synthesized by controllable hydrothermal and calcination method successfully. • N-C@P-MoS 2 with optimized loadings exhibits desirable HER activity by various nonmetal doping. • The enhanced performance is ascribed to the synergy of controllable structural effect and modified electronic effect. [ABSTRACT FROM AUTHOR]

Abstract: The project of a 14MeV PET cyclotron aiming at medical diagnosis and treatment was proposed and started at CIAE in 2010. The low-level RF system is designed to stabilize acceleration voltage and control the resonance of the cavity. Based on the experience of the existing CRM Cyclotron in CIAE, a new start-up sequence is developed and tested. The frequency sweeping is used to activate the RF system. Before the tuner is put into use, a new state called “DDS tuning” is applied to trace the resonance frequency to the designed value. This new option state helps to cover the tuning range, if a large frequency variation occurs because of a thermal cavity deformation. The logic control unit detects the spark, reflection, Pulse/CW state and the frequency of the RF source to perform all kinds of protection and state operations. The test bench and on-line test are carried out to verify the initial design. [Copyright &y& Elsevier]

CP@NC-CoFe 2 O 4 /C as catalysts for OER: we covered a polyaniline nanowire array on carbon paper by a electrochemical polymerization method, directly grown MOF-74-Co/Fe on its surface and pyrolyzed to form the CoFe 2 O 4 /C supported on nitrogen-doped carbon nanoarray meterial, which is prepared a highly active and stable OER catalyst. High specific surface area, high utilization of the catalyst, enhanced electron transport characteristics and retention characteristics of the original carbon paper characteristics ensure excellent OER activity. Our results show great promise for developing OER catalysts as precious metal substitutes for PANI and MOFs complexes through a low-cost, scalable method. [Display omitted] • Polyaniline nanowire array was covered on carbon paper, directly grown MOF-74-Co/Fe on its surface. • The presence of PANI nanowire arrays also retains the original properties of carbon paper. • The unique 3D nano-array structure enhance the OER catalytic efficiency. • DFT reveals the main surface adsorbent is OH*, and surface Co atoms are the main active sites. Here, we covered a polyaniline nanowire array (denoted as PANI) on carbon paper (denoted as CP) by a electrochemical polymerization method, directly grown MOF-74-Co/Fe on its surface and pyrolyzed to form the CoFe 2 O 4 /C supported on nitrogen-doped carbon nanoarray materials (denoted as NC-CoFe 2 O 4 /C@CP), which is prepared a highly active and stable OER catalyst. PANI can not only be used as a "binder", grow MOF on its surface and cover the carbon paper, but also improve the conductivity and stability of the material by forming nitrogen-doped carbon after pyrolysis. And its unique 3D nano-array structure not only greatly increases the surface area, but also provides more attachment sites for CoFe 2 O 4 , thereby accelerating electron transport and improving OER performance. High specific surface area, high utilization of the catalyst, enhanced electron transport characteristics and retention characteristics of the original carbon paper characteristics ensure excellent OER activity. The final sample exhibits outstanding activity for OER in alkaline solution, accompanied by a low onset potential about 1.52 V (vs reversible hydrogen electrode), and the small Tafel slope of 70 mV dec−1. In particular, after 21600s, the current drop is negligible, which is means that the NC-CoFe 2 O 4 /C@CP catalyst has the high stability. Density Functional Theory (DFT) calculation reveals the main surface adsorbent of CoFe 2 O 4 is OH*, and the surface Co atoms are the main active sites. [ABSTRACT FROM AUTHOR]

The toxicity and stability of all-inorganic perovskite quantum dots are major challenge to be addressed in its commercialization process. Here, the toxicity of lead is reduced while improving the optical properties of quantum dots via replacing Pb2+ ions in CsPbBr 3 perovskites quantum dots with low-toxicity and cost-effectiveness Cu2+ cations. The PL emission and absorption peaks of quantum dots appear blue shift due to lattice shrinkage caused by copper ion doping. At the same time, we also observed that with the increase of Cu2+ doping concentration, the fluorescence lifetime of quantum dots decreased from 40.66 ns to 8.23 ns. Next, the slim CsPbBr 3 :Cu@SiO 2 core-shell QDs were synthesized via a simply one-step synthesis method. Compared with the original CsPbBr 3 :Cu QDs, the stability of the quantum dots after coated has been significantly improved. Benefiting from this effective cladding strategy, these CsPbBr 3 :Cu@SiO 2 can be well used for manufacturing high-performance perovskite LEDs. [ABSTRACT FROM AUTHOR]