Nanosized gold particles were functionalised with two types of paramagnetic surface tags, one having a nitroxide radical and the other one carrying a DTPA complex loaded with Gd 3+ . Selective measurements of nitroxide-nitroxide, Gd 3+ -nitroxide and Gd 3+ -Gd 3+ distances were performed on this system and information on the distance distribution in the three types of spin pairs was obtained. A numerical analysis of the dipolar frequency distributions is presented for Gd 3+ centres with moderate magnitudes of zero-field splitting, in the range of detection frequencies and resonance fields where the high-field approximation is only roughly valid. The dipolar frequency analysis confirms the applicability of DEER for distance measurements in such complexes and gives an estimate for the magnitudes of possible systematic errors due to the non-ideality of the measurement of the dipole-dipole interaction.

Recently, the MXene itself and its composites with various metal oxides have shown excellent electrochemical performance due to the presence of multiple oxidation states. However, the restacking of MXene layers and poor electrical conductivity of metal oxides are major bottlenecks in their effective electrochemical transport, when they are applied individually. Herein, we report a novel manganese oxide/MXene (MnO 2 /MXene) composite material to overcome these critical issues. Sub-50 nm-thick MnO 2 nanowires (NWRs) were introduced inside the MXene to effectively stop the restacking as well as to increase the surface area of the supercapacitor (SC) electrode material. The special control on the thickness of NWRs is not only providing an opportunity to adjust them inside the MXene layers but also giving a high surface area. Electrochemical studies suggested that the MnO 2 /MXene composite behaves as an excellent electrode material for hybrid SCs, as compared to individual MXene and MnO 2 . Maximum specific capacitance (C sp ) of MXene, MnO 2 NWRs, and MnO 2 /MXene composite was observed to be about 527.8, 337.5, and 611.5 F/g, respectively. The calculated specific capacity of the MnO 2 /MXene composite was about 489.5 C/g at 1 A/g, which shows better performance as an electrode material for energy storage devices. The synthesized electrode material demonstrated excellent capacitance retention of about 96% up to 1000 cycles.

Monolayer-protected, Gd(3+)-functionalised gold nanoparticles with enhanced spin-lattice relaxivity (r(1)) were prepared; adsorption of polyelectrolytes on these materials further increased r(1) and ligand exchange with a biotin-derivatised disulfide led to a prototype avidin-targeted contrast agent.

The development of highly efficient electrode materials for high power devices is one of the cutting-edge research areas in advanced energy applications. Recently, MXene has gained tremendous interest among the research community because of its extraordinary electrochemical properties as compared to other two-dimensional layered materials such as graphene/MoS2. However, the supercapacitive performance of MXene as an electrode material is hindered by the restacking of its layers due to functional group interactions. To overcome this problem, here in this article, we explored MXene and its composites with cobalt ferrite [CoFe2O4] nanoparticles (CoF NPs) for battery-like hybrid supercapacitor applications. NPs were applied to use them as interlayer spacers between MXene layers. By the electrochemical studies, it is proved that the composite (CoF/MXene) can provide better electrochemical properties than individual ferrite or MXene. The maximum specific capacitance (C sp) of CoF NPs, MXene, and CoF/MXene composites was observed to be about 594, 1046.25, and 1268.75 Fg–1 at 1 A g–1, respectively. The calculated specific capacity (sp. capacity) of the CoF/MXene composite was about 440 Cg–1 at 1 A g–1 and proved to be an excellent hybrid electrode material by providing only 0.25 Ω charge transfer resistance. The as-synthesized material demonstrated the excellent capacitance retention, about 97%, up to 5000 cycles.

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