Electrochemically dealloyed platinum with hierarchical pore structure as highly active catalytic coating

Ralph Kraehnert,Ran Liu,Benjamin Paul,Michael Kanis,Erik Ortel,Bjoern Eckhardt,Antonia Antoniou

doi:10.1039/c4cy00851k

Abstract

Electrochemical dealloying of Pt–Si produces Pt films with hierarchical pore structure and superior performance in butadiene hydrogenation.

Highlights

The most common method of immobilizing catalysts in micro-structured reactors is the filling or wash-coating of reactor walls with a slurry prepared from conventional powder catalysts
The dealloyed Pt–Si coatings were analyzed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), SAED and N2 sorption in order to reveal the materials morphology and pore structure
Cross section Scanning Electron Microscope (SEM) images indicate that the pore system consists of porous columnar structures (Fig. 1B1) and that the columnar structures are connected by thin pore walls (Fig. 1B2)

Summary

Introduction

The most common method of immobilizing catalysts in micro-structured reactors is the filling or wash-coating of reactor walls with a slurry prepared from conventional powder catalysts. All of the catalytic coatings reported so far resemble in their structure and composition classical supported catalysts that had been designed for conventional packed-bed reactors. These catalytic coatings inherit the typical activity of the respective catalyst powders. Chemical methods include reduction of a metal precursor in presence of a porous hard template (e.g. mesoporous Pt templated by KIT-622), reduction in presence of a surfactants lyotropic phase[23] and self-assembly of ligand-stabilized colloidal metal nanoparticles, e.g. in the presence of block copolymers.[24] these syntheses typically produce mechanically fragile agglomerates and powders, not extended homogeneous and mechanically stable films coated to a substrate material from which a catalytic micro reactor could be manufactured. The performance of differently dealloyed catalysts in the gasphase hydrogenation of butadiene is studied and discussed in context of available literature data (3.3)

Catalyst synthesis

Sample characterization

Catalytic tests in butadiene hydrogenation

Results and discussion

Conclusions