Ru1/FeOx single-atom catalyst with dual active sites for water gas shift reaction without methanation

Abstract

Ru-based catalysts are rarely considered for water gas shift (WGS) reaction due to either inferior activity or methanation side reaction. Here, Ru1/FeOx single-atom catalyst is synthesized via a co-precipitation method, which can realize high CO conversion with low loading of 0.18 wt. % and stable specific rates with ~3 times higher than Ru nanoparticles (NPs) with loading of 2.00 wt. % at 300 °C. Moreover, it shows no formation of methanation byproducts even under CO2- and H2-rich WGS stream which can occur on Ru NPs. Detailed characterizations demonstrate that Ru single atoms have stronger interaction with FeOx to form dual active sites for WGS reaction. The positive Ru1 species own rather weaker bonded CO* and the neighbored FeOx can help activate H2O to generate OH*, which then react facilely via an associative process. Meanwhile, the single atom Ru prohibits the dissociation of H2 with low adsorption strength to avoid the methanation.