Watching mesoporous metal films grow during templated electrodeposition with in situ SAXS.

S J Richardson,M R Burton,X Luo,A M Squires,J M Elliott,P A Staniec,I S Nandhakumar,N J Terrill

doi:10.1039/c7nr03321d

Abstract

In this paper, we monitor the real-time growth of mesoporous platinum during electrodeposition using small-angle X-ray scattering (SAXS). Previously, we have demonstrated that platinum films featuring the 'single diamond' (Fd3m) morphology can be produced from 'double diamond' (Pn3m) lipid cubic phase templates; the difference in symmetry provides additional scattering signals unique to the metal. Taking advantage of this, we present simultaneous in situ SAXS/electrochemical measurement as the platinum nanostructures grow within the lipid template. This measurement allows us to correlate the nanostructure appearance with the deposition current density and to monitor the evolution of the orientational and lateral ordering of the lipid and platinum during deposition and after template removal. In other periodic metal nanomaterials deposited within any of the normal topology liquid crystal, mesoporous silica or block copolymer templates previously published, the template and emerging metal have the same symmetry, so such a study has not been possible previously.

Highlights

Mesoporous materials have wide reaching applications in the field of nanotechnology
We present simultaneous in situ small-angle X-ray scattering (SAXS)/electrochemical measurement as the platinum nanostructures grow within the lipid template
A platinum film growing with the Fd3m symmetry and double the unit cell size of the lipid QDII phase gives a distinct additional reflection, as we demonstrate here, confirming our original hypothesis that it grows as an asymmetric single diamond structure

Summary

Introduction

Mesoporous materials have wide reaching applications in the field of nanotechnology. Their high internal surface area and ordered nature have led to their use in catalysis,[1,2] drug delivery,[3] sensors,[4,5] batteries[6] and solar cells.[7,8,9] Ordered nanostructured films periodic in two or three dimensions are commonly produced by electrodeposition within a block copolymer,[10] mesoporous silica[11,12] or lyotropic liquid crystalline template.[13]. We have demonstrated that platinum films featuring the ‘single diamond’ (Fd3m) morphology can be produced from ‘double diamond’ (Pn3m) lipid cubic phase templates; the difference in symmetry provides additional scattering signals unique to the metal.

Results

Conclusion