Submillisecond Laser Annealing Induced Surface and Subsurface Restructuring of Cu-Ni-Pd Trimetallic Nanocatalyst Promotes Thermal CO₂Reduction

The heterogeneous catalysis on CO2 reduction reaction (CO2RR) via thermal route is a promising approach for converting waste chemicals and heat into synthetic fuels. For optimum functionality of transition-metal-based nanocatalysts (NC)s, herein, trimetallic NC comprising multiple metal-to-metal oxide interfaces between Cu/CuOx-Ni/NiOx-Pd in subnanometer-sized domains is fabricated on carbon nanotube (CNT) support via proper control on surface chemisorption and subsequent reduction of metal ions (denoted as CNP). Furthermore, to delve more deeply into the CO2RR performance, as-prepared CNP NC is subjected to submillisecond pulsed laser annealing with different per pulse energies (1 mJ and 10 mJ) and a fixed duration of 10 s for manipulating the local atomic arrangement on the surface as well as subsurface regions. In the quasi-balance between the photon annealing and thermal quenching kinetics, the long-range ordered metastable phases of Ni-Pd and Cu-Pd alloys are formed after laser treatment. For the optimum condition (10 mJ per pulse energy input), the production yield and selectivity of CO for the CNP NC in the ambient of CO2 and H2 mixture (H2/CO2 = 3.0) are respectively improved by 27% and 22.4% at 573 K. These results demonstrate the capability for developing the heterogeneous NCs with local and long-range ordered structures for high CO selectivity in CO2RR by using submillisecond pulsed laser annealing that is a quantum leap in reducing the energy input and cost for commercial and environmental benefits.