Preparation of palladium-based catalyst by plasma-assisted atomic layer deposition and its applications in CO₂ hydrogenation reduction

Abstract

Supported Pd catalyst is an important noble metal material in recent years due to its high catalytic performance in CO2 hydrogenation. An fluidized-bed plasma assisted atomic layer deposition (FP-ALD) process is reported to fabricate Pd nanoparticle catalyst over γ-Al2O3 or Fe2O3/γ-Al2O3 support, using palladium hexafluoroacetylacetonate as the Pd precursor and H2 plasma as counter-reactant. Scanning transmission electron microscopy exhibits that high-density Pd nanoparticles are uniformly dispersed over Fe2O3/γ-Al2O3 support with an average diameter of 4.4 nm. The deposited Pd-Fe2O3/γ-Al2O3 shows excellent catalytic performance for CO2 hydrogenation in a dielectric barrier discharge reactor. Under a typical condition of H2 to CO2 ratio of 4 in the feed gas, the discharge power of 19.6 W, and gas hourly space velocity of 10000 h-1, the conversion of CO2 is as high as 16.3 % with CH3OH and CH4 selectivities of 26.5 % and 3.9 %, respectively.