NbOPO4 Supported Rh Nanoparticles with Strong Metal-Support Interactions for Selective CO2 Hydrogenation.

Strong metal-support interactions (SMSI) could improve the performance of nanoparticle catalysts through the electronic and geometric modulation of the reducible metal oxide supports. Here, SMSI is demonstrated to occur for catalysts with non-oxide carrier, such as NbOPO4 -supported Rh nanoparticles, under reduction treatment at low temperature. During CO2 hydrogenation, this Rh/NbOPO4 catalyst with SMSI exhibits impressive CO selectivity at high CO2 conversion in a wide temperature range with hindered methanation. For example, over 98.9 % CO selectivity was obtained with 39.9 % CO2 conversion at 500 °C. Mechanism investigations demonstrate that the SMSI results in the formation of a metal-support interface with weaker CO adsorption than the metallic Rh sites, thus accelerating the CO desorption, which hinders deep hydrogenation. Rh nanoparticles with small diameter of about 1.1 nm is sinter-resistant with unchanged performance during a long-period test. This work might extend the investigation of SMSI from oxides to phosphate supports, which helps optimizing the selectivity and stability of metal nanoparticle catalysts.