No abstract

The self-assembly of two-dimensional (2D) nanostructures into one-dimensional (1D) nanoarchitectures may result in materials which combine the unique physicochemical properties of 2D nanostructures with the excellent charge transport properties of 1D architectures. Herein, we report the self-stacking of 2D nickel−cobalt (Ni−Co) phosphate nanoplates into 1D chainlike architectures with the assistance of metal glycerates as self-templates. This unique selfassembly process is driven by the adsorbed ethyl glycerate on the surface of the individual nanoplates, which promotes the subsequent growth of the new nanoplate on top of the previously formed nanoplate, thereby leading to the self-stacking of these nanoplates along the vertical direction. The flexibility of the proposed method is also highlighted by the feasible preparation of nickel phosphate with the same self-assembled structure. When tested as a catalyst for oxygen evolution reaction (OER) in an alkaline medium, the bimetallic Ni−Co phosphate (derived from Ni-Co-TEP) with the nanoplate-assembled chainlike structure displays much lower overpotential (η 10 = 310 mV) and Tafel slope (68 mV dec −1 ) than its pristine counterparts. The enhanced OER activity of this bimetallic catalyst may be attributed to (i) the highly interconnected structure and the bimetallic composition which promote improved charge transport; (ii) the porous chainlike structure which provides increased number of active sites, facilitates easier electrolyte infiltration, and promotes good electrical contact with the electrolyte, and (iii) the presence of Ni 3+ and Co 3+ active sites (nickel−cobalt (oxy)hydroxides) which can promote the chemisorption of OH − and facilitate electron transfer from the OH − to the surface Ni/Co sites during OER.

This work reports the fabrication of bimetallic nickel–cobalt hydrogen phosphate with unique nanotube-assembled 1D and 2D architectures for electrocatalytic OER.

The recent development of nanoscale fillers, such as carbon nanotube, graphene, and nanocellulose, allows the functionality of polymer nanocomposites to be controlled and enhanced. However, conventional synthesis methods of polymer nanocomposites cannot maximise the reinforcement of these nanofillers at high filler content. Approaches to the synthesis of high content filler polymer nanocomposites are suggested to facilitate future applications. The fabrication methods address design of the polymer nanocomposite architecture, which encompass one, two, and three dimensional morphology. Factors that hamper the reinforcement of nanostructures, such as alignment, dispersion of filler as well as interfacial bonding between filler and polymer are outlined. Using suitable approaches, maximum potential reinforcement of nanoscale filler can be anticipated without limitations in orientation, dispersion, and the integrity of the filler particle-matrix interface. High filler content polymer composites containing emerging materials such as 2D transition metal carbides, nitrides, and carbonitrides (MXenes) are expected in the future.Graphical abstract: Approaches to the synthesis of high filler content polymer composites

Layered double hydroxides (LDHs) containing first‐row transition metals such as Fe, Co, and Ni have attracted significant interest for electrocatalysis owing to their abundance and excellent performance for the oxygen evolution reaction (OER) in alkaline media. Herein, the assembly of holey iron‐doped nickel‐cobalt layered double hydroxide (NiCo‐LDH) nanosheets (‘holey nanosheets’) is demonstrated by employing uniform Ni–Co glycerate spheres as self‐templates. Iron doping was found to increase the rate of hydrolysis of Ni–Co glycerate spheres and induce the formation of a holey interconnected sheet‐like structure with small pores (1–10 nm) and a high specific surface area (279 m2 g−1). The optimum Fe‐doped NiCo‐LDH OER catalyst showed a low overpotential of 285 mV at a current density of 10 mA cm−2 and a low Tafel slope of 62 mV dec−1. The enhanced OER activity was attributed to (i) the high specific surface area of the holey nanosheets, which increases the number of active sites, and (ii) the improved kinetics and enhanced ion transport arising from the iron doping and synergistic effects.