Facile surface restructure by one-step sub-millisecond laser exposure promotes the CO2 methanation performance of cobalt oxide supported Pd nanoparticles with copper-oxide cluster decoration

Carbon dioxide (CO2) methanation not only mitigates excessive CO2 emissions but also circumvents the difficulties associated with the storage and transportation of low-grade energies. However, the competitive reverse water gas shift (RWGS) reaction severely hampers the productivity of methane (CH4). In this context, a tri-metallic nanocatalyst (NC) comprising atomic CuOx cluster anchored Pd nanoparticles (NP)s on the cobalt-oxide support (hereafter denoted as CPCu) is developed. Furthermore, to optimize the CO2 methanation performance, the surface and sub-surface atomic arrangements of the as-prepared CPCu NCs were altered by a sub-millisecond pulsed laser irradiation with per pulse energies of 1 mJ and 10 mJ for a fixed duration of 10 s. For the optimum case (1 mJ per pulse energy input; denoted as CPCu-1), the CPCu-1 NC delivers an optimum CH4 productivity of ∼1346 mmol g−1 h−1 at 300 °C temperature, which is 13.6% enhanced as compared to the pristine conditions (∼1164 mmol g−1 h−1). On top of that, the CH4 selectivity is improved by 40% for CPCu-1 NCs as compared to the as-prepared conditions. The cross-referencing results of physical characterization along with electrochemical analysis indicate that such an improved activity and selectivity of CPCu-1 NCs originate from the significant surface restructure of CPCu-1 NCs, where the high density of surface exposed atomic CuOx species and neighbouring Pd sites, respectively, promotes CO2 activation and H2 dissociation steps during CO2 methanation. We believe that the obtained results will provide insight into designing high-performance catalytic materials for CO2 methanation by using sub-millisecond pulsed laser irradiation.