Intermetallic GaPd2 Thin Films for Selective Hydrogenation of Acetylene

René R Zimmermann,Marc Armbrüster,Martin Siebert,Shyjumon Ibrahimkutty,Roland Dittmeyer

doi:10.1002/zaac.202000124

Abstract

The preparation of single‐phase and catalytically active GaPd2 coatings was accomplished via DC magnetron sputtering using an intermetallic sputter target. Thin and uniform layers were deposited on borosilicate glass, Si(111) and planar as well as micro‐structured stainless steel foils. The specimens were examined regarding their phase composition, film morphology and microstructure. Thin films of different layer thickness were catalytically characterized in the semi‐hydrogenation of acetylene, which was conducted at 473 K and a feed gas composition of 0.5 vol.% C2H2, 5 vol.% H2 as well as 50 vol.% C2H4 in helium. Pre‐reduction of the catalyst was found to be essential to enhance the catalytic selectivity. Sputtered GaPd2 showed a high selectivity of 73 % for the hydrogenation to ethylene at conversion levels above 80 %. The surface‐specific activity was strongly increased to 8.97 molacetylene·(A0·h)–1 compared to bulk‐ or nanoscale GaPd2 (1.93 and 0.30 molacetylene·(A0·h)–1, respectively) caused by the high specific surface area of the thin films.

Highlights

Catalyzed selective hydrogenations are important reactions, which are applied in several industrial processes
Thin films of the intermetallic compound GaPd2 were successfully deposited as single phase on several substrates by DC magnetron sputtering
Differences of the phase composition were pronounced for very thin films Յ 60 nm, as the powder diffraction pattern after annealing at 723 K for 4 h revealed reflections that could be assigned to intermetallic GaPd2

Summary

Introduction

Catalyzed selective hydrogenations are important reactions, which are applied in several industrial processes. Compact and uniform GaPd2 layers were successfully deposited on borosilicate glass, Si(111) and stainless steel via DC magnetron sputtering using the intermetallic target.

Results

Conclusion