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

Abstract

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.