Block Copolymer Templated Platinum Electrocatalysts from Various Fabrication Pathways: A Comparative Study

Abstract

PGMs (Platinum Group Metals) are state-of-the-art electrocatalysts for electrochemical energy conversion technologies such as fuel cells and electrolyzers. Fabrication of PGM electrocatalysts templated from self-assembled block copolymer thin films is interesting because they allow precise control over nanoscale feature size and morphology. In our previous work, the mass activity of such electrocatalysts, developed via incipient wetness impregnation, were probed as a function of their feature sizes (~ 11 – 35 nm). This talk presents a comparative electrochemical study of block copolymer templated platinum electrocatalysts prepared from three different pathways (i) incipient wetness impregnation (ii) physical vapor deposition (iii) atomic layer deposition. A combination of electron microscopy, atomic force microscopy, grazing incidence x-ray scattering, x-ray photoelectron spectroscopy, and inductively coupled plasma – optical emission spectrometry was used to characterize PGM geometry and chemical composition. It was found that all studied methods lead to high-fidelity pattern transfer from the block copolymer thin film to the PGM mesostructures. Electrocatalytic activity for HOR/HER and water-splitting were assessed for the various samples prepared. The versatility of fabrication of thin film meso-structured electrocatalysts from self-assembled block copolymers allows for systematic evaluation how PGM deposition method and thin film morphology influence electrochemical reactivity.