Use of cubic structure with primitive nanochannels for fabrication of free standing 3D nanowire network of Pt with Pm3m symmetry

Abstract

In this work, we developed a lipid mixture based on phytantriol / polyoxyethylene surfactant (Brij-56) that forms a Im3m symmetry bicontinuous cubic phase based on the Schwartz primitive surface (Q II P ), from which we templated highly ordered 3D nanoporous platinum with a novel ‘single primitive’ morphology (Pm3m symmetry). The Q II P template phase is obtained by incorporation of 17.5% w/w Brij-56 (C16EO10) (a type-I surfactant) into phytantriol under excess hydration conditions. Phytantriol alone forms the double diamond Q II D (Pn3m) phase, and in previous studies incorporating Brij-56 at different compositions the cubic phase maintained this morphology, but increased its lattice parameter; mesoporous metals templated from these Q II D lipid templates all exhibited the ‘single diamond’ (Fd3m) morphology. In contrast, the current paper presents the availability of our Q II P cubic phases to template nanoporous materials of single primitive Pm3m morphology via chemical and electrochemical methods. To explore the structure porosity and morphological features of the templated Pt material, x-ray scattering and transmission electron microscopy are used. The resulting 3D nanoporous Pt materials are found to exhibit a regular network of Pt nanowires of ∼4 nm in diameter with a unit cell dimension of 14.8 ± 0.8 nm, reflecting the aqueous network within the Q II P template.