Amorphous Modulation of Atomic Nb-O/N Clusters with Asymmetric Coordination in Carbon Shells for Advanced Sodium-Ion Hybrid Capacitors.

Anode materials with excellent properties have become the key to develop sodium-ion hybrid capacitors (SIHCs) that combine the advantages of both batteries and capacitors. Amorphous modulation is an effective strategy to realize high energy/power density in SIHCs. Herein, atomically amorphous Nb-O/N clusters with asymmetric coordination are in situ created in N-doped hollow carbon shells (Nb-O/N@C). The amorphous clusters with asymmetric Nb-O3/N1 configurations have abundant charge density and low diffusion energy barriers, which effectively modulate the charge transport paths and improve the reaction kinetics. The clusters are also enriched with unsaturated vacancy defects and isotropic ion-transport channels, and their atomic disordering exhibits high structural stress buffering, which are strong impetuses for realizing bulk-phase-indifferent ion storage and enhancing the storage properties of the composite. Based on these features, Nb-O/N@C achieves notably improved sodium-ion storage properties (reversible capacity of 240.1 mAh g-1 at 10.0 A g-1 after 8000 cycles), and has great potential for SIHCs (230 Wh Kg-1 at 4001.5 W Kg-1). This study sheds new light on developing high-performance electrodes for sodium-ion batteries and SIHCs by designing amorphous clusters and asymmetric coordination.

CoP-modified CdS for enhanced stability and photocatalytic hydrogen production under visible light.

The weak electron-hole separation ability and the more severe photocorrosion of CdS largely limit its hydrogen precipitation performance. In this study, CoP loading on the surface of CdS was utilized to form a type I heterojunction. The photocurrent density increased from 2 µA cm-2 to 20 µA cm-2. When the loading of CoP was 10%, the best photocatalytic performance reached 4.43 mmolg-1 h-1 under visible light, which was 20.1 times higher than that of CdS (0.22 mmolg-1 h-1). In addition, the loading of CoP solved the problem of CdS photocorrosion. After 5 cycles of simulated solar irradiation, the performance of 10% CoP/CdS remained at 93% of the initial test. This work provides new ideas for the design of low photocorrosion and high-performance catalysts.

Patterned Ni-P alloy films prepared by "reducing-discharging" process and the hydrophobic property.

Patterned hydrophobic Ni-P alloy films consisting of orderly and regular micro-nanoscale particles were fabricated through the synergistic effect of electrochemical deposition and chemical deposition. Ni-P alloy films were deposited for different times and characterized by scanning electron microscope (SEM). It was confirmed that the addition of reducing agent induced the formation of nanoscale particles, in contrast with pure Ni film deposited by single electrochemical deposition. As "point-discharge effect", the current density was higher at the edge of the nanoscale particles, and Ni ions would be deposited at the particles through the "point-discharge effect". Then the Ni-P alloy films grew by "reducing-discharging" process. The X-ray photoelectron spectroscopy (XPS) was used to detect the composition and valence states of these alloy films. The existence of oxidation state of element P in these films corresponding to that in H2PO3(-), also gave direct evidence for the occurrence of chemical deposition, during the electrochemical deposition process. The prolongation of deposition time could provide more time for the patterned morphology to grow up. The surface roughness, evaluated by surface profilometer, increased as the deposition time extension. And these films showed gradually increased hydrophobic properties with the increase in deposition time.