The heterogeneous catalysis on CO 2 reduction reaction (CO 2 RR) 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 subnanometersized 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 CO 2 RR 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 CO 2 and H 2 mixture (H 2 /CO 2 = 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 CO 2 RR by using submillisecond pulsed laser annealing that is a quantum leap in reducing the energy input and cost for commercial and environmental benefits.

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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, the CoPd-10 nanocatalyst exhibited the highest CO production yield of ∼1667 μmol g−1catalyst, with a CO selectivity of ∼88% at a temperature of 573 K, which is a 41% improvement over pristine CoPd (~976 μmol g−1catalyst). 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 H2 splitting steps. In addition, the cobalt oxide support helped to donate electrons to Pd, thereby enhancing its ability of H2 splitting. These results provide a strong foundation to use sub-millisecond laser irradiation for catalytic applications.

We design a high-speed inductive-peaking Si microring modulator integrated with an on-chip spiral inductor to extend the 3dB operating bandwidth beyond 65GHz and increase the conversion gain by 5 dB. A 64Gb/s transmission is demonstrated.

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