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Capacitive deionization (CDI) is an emerging desalination technology that still needs further development to enhance its performance for practical implementation. Herein, we present a hybrid CDI approach, which integrates the electrical double-layer (EDL) with the sodium-ion battery concept to improve the separation of sodium and chloride ions from saline water. The hybrid CDI cell is achieved by using hydrothermally-grown and uniformly dispersed prawn-like α-MnO₂/graphene (α-MnO₂/G) nanocomposite as anode material, and graphene at the cathode. In this paper, the effect of MnO₂ morphology on the electrode electrochemical performance and its effect on capacitive deionization performance have been fully investigated. In this configuration, the Na⁺ ions are inserted by the electrochemical reaction at the α-MnO₂/G electrode, whereas Cl⁻ ions are captured by the graphene-based electrode. The morphological dependent electrochemical properties of the obtained nanocomposites were studied deeply through CV and EIS analysis. The established hybrid CID cell provides an electrical capacitance as high as 375 F g⁻¹ at 10 mV s⁻¹, cation-selectivity, good electrical stability and low internal resistance. The hybrid CDI device also shows a stable and reversible salt insertion/de-insertion capacity up to 29.5 mg g⁻¹ at 1.2 V. These results demonstrate the suitability of prawn-like α-MnO₂/G nanocomposite to produce high-performance hybrid CDI cells.

We have investigated the electronic and magnetic properties of zigzag nanoribbons (ZNRs) of arsenene and antimonene both in black phosphorene (BP) phase and hexagonal phase by using first principles calculations. Firstly, a novel metallic edge state emerges in the mid of the bulk band gap for ZNRs of all the systems. Secondly, edge magnetism have also been systematically studied for these systems by considering different magnetic configurations. An intra-edge antiferromagnetic semiconducting state is found to be the ground state for the ZNRs of arsenene and antimonene. Since the edges of ZNRs are easily saturated by Hydrogen and Oxygen atoms when the samples are exposed to the air in the experiment, we further investigate influence of edge passivation of Hydrogen or Oxygen atoms and find the edge magnetism vanished under H-passivation but still restored under O-atoms passivation. Thus the electronic and magnetic properties of the ZNRs can be effectively controlled by intentionally passivation with various elements. We hope these interesting electronic and magnetic properties of the ZNRs of arsenene/antimonene are useful for future applications in nanoelectronic and spintronic devices.

The enduring goal in condensed matter physics is to search for controlled magnetism in semiconducting materials. Based on first principles DFT calculations, we systematically investigate the electronic and magnetic properties of zigzag arsenene nanoribbons (ZAsNRs). We find that metallic edge states originate in the middle of bulk band gap for different widths of ZAsNRs due to electronic instability. Besides, edge magnetism for different magnetic configurations of ZAsNRs, have been investigated to remove these instabilities. There occurs a transition from non-magnetic to magnetic and metallic to semi-conducting edge states and as a result an intra-edge antiferromagnetic (AFM) semiconducting ground state has been found. In order to tune the edge states, strain engineering is employed on magnetic ground state and found that at critical value of compressive strains (−6%), there happens a transition from magnetic to nonmagnetic (NM) and semiconductor to metal. We expect that these semiconducting properties can be controlled by edge magnetism and strain engineering and make ZAsNRs a best semiconducting material which can be used as promising candidate for device applications in semiconducting industry.

In view of the growing concern about energy management issues, sodium ion batteries (SIBs) as cheap and environmentally friendly devices have increasingly received wide research attentions. The high current rate and long cycle-life of SIBs are considered as two key parameters determining its potential for practical applications. In this work, the rigid single-crystalline anatase TiO2 nanosheets (NSs) with a thickness of ∼4 nm has been firstly prepared, based on which a stable nanostructured network consisting of ultrathin anatase TiO2 NSs homogeneously anchored on graphene through chemical bonding (TiO2 NSs-G) has fabricated by hydrothermal process and subsequent calcination treatment. The morphology, crystallization, chemical compositions and the intimate maximum contact between TiO2 NSs and graphene are confirmed by TEM, SEM, XRD, XPS and Raman characterizations. The results of electrochemical performance tests indicated that the TiO2 NSs-G hybrid network could be consider as a promising anode material for SIBs, in assessment of its remarkably high current rate and long cycle-life aside from the improved specific capacity, rate capability and cycle stability.

Taking advantages of the monodisperse TiO2 nanosheets (NSs) with high active crystal face exposure and the tunable localized surface plasmon resonance (LSPR) properties of Au@Ag nanorods (NRs), this study demonstrated that TiO2 NSs film with trace amount of Au@Ag NRs modification possess a strong enhancement of photocurrent response, which was remarkably inhibited with the addition of mercury (II) ions (Hg(2+)). Based on the selective decrease of photocurrent with the addition of Hg(2+), a simple photoelectrochemical (PEC) sensor has been assembled. The PEC sensor exhibits wide linear range (0.01-10nM), low detection limit (2.5 pM), satisfying selectivity, reproducibility and acceptable stability for Hg(2+) detection. The feasibility of this method for practical application in human serum has been evaluated and the result was satisfactory. This PEC sensing method would provide a potential application for Hg(2+) detection in clinical diagnosis.

In this work, we present a new versatile strategy to prepare noble metal (Au, Ag and Cu) nanoclusters on TiO2 nanosheets in large scales with exposed (001) facets with controlled size, crystalline interface, and loading amount. By precise in situ calcination, the metal (M = Au, Ag, and Cu) nanocrystals with controllable size and better crystalline interface with the TiO2 support have been prepared. The potential application of the as-prepared Au, Ag, and Cu nanoclusters on TiO2 nanosheets as potential heterogeneous catalysts for organic synthesis, such as catalytic reduction of 4-nitrophenol to 4-aminophenol, has been demonstrated. After calcination, Au, Ag, and Cu nanocrystals were found to be proficient cocatalysts for photocatalytic H2 evolution, particularly the Au cocatalyst. Based on precise high-resolution transmission electron microscopy (HRTEM) and inductively coupled plasma optical emission spectrometry (ICP-OES) analyses, the flexible control of their size and loading amount as well as their intimate contact with the TiO2 nanosheet enhanced the photocatalytic H2 evolution activity and the sensitivity of the photocurrent response of the film. Furthermore, this aqueous-directed synthesis of metal nanoclusters on a support will generate further interest in the field of nanocatalysis.

This study reports the controllable surface roughening of Au–Ag alloy nanoplates via the galvanic replacement reaction between single-crystalline triangular Ag nanoplates and HAuCl4 in an aqueous medium. With a combination of experimental evidence and finite element method (FEM) simulations, improved electromagnetic field (E-field) enhancement around the surface-roughened Au–Ag nanoplates and tunable light absorption in the near-infrared (NIR) region (~800–1,400 nm) are achieved by the synergistic effects of the localized surface plasmon resonance (LSPR) from the maintained triangular shape, the controllable Au–Ag alloy composition, and the increased surface roughness. The NIR light extinction enables an active photothermal effect as well as a high photothermal conversion efficiency (78.5%). The well-maintained triangular shape, surface-roughened evolutions of both micro- and nanostructures, and tunable NIR surface plasmon resonance effect enable potential applications of the Au–Ag alloy nanoplates in surface-enhanced Raman spectroscopic detection of biomolecules through 785-nm laser excitation.

Taking advantages of the monodisperse TiO2 nanosheets (NSs) with high active crystal face exposure and the tunable localized surface plasmon resonance (LSPR) properties of Au@Ag nanorods (NRs), this study demonstrated that TiO2 NSs film with trace amount of Au@Ag NRs modification possess a strong enhancement of photocurrent response, which was remarkably inhibited with the addition of mercury (II) ions (Hg(2+)). Based on the selective decrease of photocurrent with the addition of Hg(2+), a simple photoelectrochemical (PEC) sensor has been assembled. The PEC sensor exhibits wide linear range (0.01-10nM), low detection limit (2.5 pM), satisfying selectivity, reproducibility and acceptable stability for Hg(2+) detection. The feasibility of this method for practical application in human serum has been evaluated and the result was satisfactory. This PEC sensing method would provide a potential application for Hg(2+) detection in clinical diagnosis.