Sub-Millisecond Laser-Irradiation-Mediated Surface Restructure Boosts the CO Production Yield of Cobalt Oxide Supported Pd Nanoparticles

The catalytic conversion of CO2 into valuable commodities has the potential to balance ongoing energy and environmental issues. To this end, the reverse water-gas shift (RWGS) reaction is a key process that converts CO2 into CO for various industrial processes. However, the competitive CO2 methanation reaction severely limits the CO production yield; therefore, a highly CO-selective catalyst is needed. To address this issue, we have developed a bimetallic nanocatalyst comprising Pd nanoparticles on the cobalt oxide support (denoted as CoPd) via a wet chemical reduction method. Furthermore, the as-prepared CoPd nanocatalyst was exposed to sub-millisecond laser irradiation with per-pulse energies of 1 mJ (denoted as CoPd-1) and 10 mJ (denoted as CoPd-10) for a fixed duration of 10 s to optimize the catalytic activity and selectivity. For the optimum case, Lthe CoPd-10 nanocatalyst exhibited the highest CO production yield of similar to 1667 mu mol g(-1) (catalyst,) with a CO selectivity of similar to 88% at a temperature of 573 K, which is a 41% improvement over pristine CoPd (similar to 976 mu mol g(-1) catalyst). The in-depth analysis of structural characterizations along with gas chromatography (GC) and electrochemical analysis suggested that such a high catalytic activity and selectivity of the CoPd-10 nanocatalyst originated from the sub-millisecond laser-irradiation-assisted facile surface restructure of cobalt oxide supported Pd nanoparticles, where atomic CoOx species were observed in the defect sites of the Pd nanoparticles. Such an atomic manipulation led to the formation of heteroatomic reaction sites, where atomic CoOx species and adjacent Pd domains, respectively, promoted the CO2 activation and H-2 splitting steps. In addition, the cobalt oxide support helped to donate electrons to Pd, thereby enhancing its ability of H-2 splitting. These results provide a strong foundation to use sub-millisecond laser irradiation for catalytic applications.

Automated summary

The catalytic conversion of CO2 into valuable commodities is important, and the reverse water-gas shift (RWGS) reaction plays a key role in this process. However, the CO2 methanation reaction limits the CO production yield, so a highly CO-selective catalyst is needed. In this study, a bimetallic nanocatalyst, CoPd, was developed and laser irradiation was used to optimize its catalytic activity and selectivity. The CoPd-10 nanocatalyst showed the highest CO production yield with improved selectivity, which was attributed to surface restructuring and formation of heteroatomic reaction sites.