Control on Pt-containing ordered honeycomb mesoporous nanostructures via self-assembly of block copolymer.

Control on the mesoporous nanostructures with uniform-sized and well-arranged mesopores can provide enhanced surface areas and mechanical properties, which are preferred for the development of energies, sensors, and electro-optical devices. Herein, Pt-containing ordered honeycomb (Pt/OHC) nanocomposites with regularly arranged mesopores were synthesized via self-assembly of polystyrene- block -poly(4-vinylpyridine) (PS- b -P4VP) block copolymers (BCPs), following mechanism study of morphological evolution, concept of structural control, potential in catalyst application, and exploration of various metals. Particularly, it was found that the self-assembly of BCP directed the ordered arrangement of the mesopores, whereas the P4VP blocks incorporated Pt and precisely positioned it on the pore walls and on the outer surface of the honeycomb matrix. Mono- to multi-layered Pt/OHCs could be generated by controlling the thicknesses of the self-assembled pristine templates, and the average diameters of the mesopores could be varied from 12 nm to 40 nm by tuning the PS:P4VP block mass ratios. The obtained Pt/OHC demonstrated promising application as electrocatalysts in hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), for which an overpotential of 39 mV at current density of 10 mA/cm2 (η 10) and a high half wave potential (E 1/2) of 0.87 V (vs. RHE), respectively, were observed in acidic media. In addition, the strategy developed here could be expanded for other metals, such as Au and Ir, to be incorporated into the ordered honeycomb matrix, providing a robust method to synthesize metal-containing mesoporous nanomaterials. With this work, we aim to offer an insight of designing ordered mesoporous nanocomposites, a concept of control over the mesoporous nanostructures, and a potential for their application in electrocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]