Surface anchored atomic cobalt-oxide species coupled with oxygen vacancies boost the CO-production yield of Pd nanoparticles

Abstract

Catalytic transformation of CO₂ into CO via the reverse water gas shift (RWGS) reaction is a potential route for establishing a closed carbon loop. However, considering the competitive Sabatier reaction, the catalytic performance is at the heart of the process. In this context, we have developed a novel nanocatalyst (NC) composed of oxygen vacancy (OV) enriched atomic CoO_x cluster (CoO_OV) decorated Pd nanoparticles (NPs) on the cobalt-oxide support underneath (denoted as CoPd–CoO_OV). The as-prepared CoPd–CoO_OV NC initiated the RWGS reaction at a temperature of 423 K in the reaction gas (CO₂ : H₂ = 1 : 3) while delivering an optimum CO production yield of ∼4052 μmol per g catalyst with a CO selectivity of ∼94% at a temperature of 573 K. The cross-referencing results of physical investigations combined with electrochemical analysis suggest that such a high activity and selectivity of the CoPd–CoO_OV NC originates from the synergistic cooperation between the neighbouring active sites on its surface, where the high density of OV and adjacent Pd domains synergistically trigger CO₂ activation and H₂ dissociation, respectively. Besides, the cobalt oxide support underneath served as an electron donor to Pd domains for facilitating H₂ splitting. We envision that the obtained results will motivate for designing highly active and selective catalysts for the RWGS reaction.