It is highly desired yet challenging to strategically steer carbon dioxide (CO2) electroreduction reaction (CO2ER) toward ethanol (EtOH) with high activity, which provides a promising way for intermittent renewable energy reservation. Controlling spatial distance between the adjoining active centers and promoting the CC coupling progress are crucial to realize this purpose. Herein, ultrathin 2D Cu2‐xSe is prepared with abundant Se vacancies, where the spatial distance between the CuCu around the Se vacancies is effectively shortened because of the lattice stress. Besides, the moderate spatial distance induced by Se vacancies can significantly decrease the Gibbs free energy of asymmetric *CO*CHO coupling progress, effectively change the local charge distribution, decrease the valence state of Cu atoms and increase the electron‐donating capacity of the dual active sites. Combining experimental observations and density functional theory simulations, the CuCu dual sites with spatial distance of 2.51 Å in VSe‐Cu2‐xSe sample can catalyze CO2ER to EtOH with high selectivity in a potential range from −0.4 to −1.6 V, and reach the highest faradaic efficiency of 68.1% at −0.8 V. This work reveals the influence of spacing effect on ethanol selectivity, and provides a new idea for future design of catalysts with chain elongation reaction, which can bring extensive attention.
Photoelectrocatalytic
(PEC) reduction of carbon dioxide (CO2) could combine the
advantages of photocatalysis and electrocatalysis
and reduce CO2 into high value-added chemical products
in mild conditions. However, the activities of catalysts and selectivities
of products are still not satisfactory because of the limited mass
transfer progress and the complex electric field environment around
active sites. In the work, PEC CO2 conversion to CO is
realized efficiently by plasmonic Au NRs in a new continuous flow
cell reactor. Benefiting from the rapid mass transfer process and
the high concentration of CO2 on the Au NRs surface, the
photocurrent density in the continuous flow cell reactor is about
1.0 mA cm–2, which is about 5 times that in the
traditional H-cell reactor (0.17 mA cm–2). Besides,
the Faraday efficiency of CO increased about 20% under light illumination
resulting from the LSPR effect of Au NRs. The DFT calculation is also
used to compare the adsorption energies of CO2 and CO on
the surfaces of Au NRs, explaining the reasons for the higher activities
and selectivities of Au NRs in a new flow-cell reactor. In summary,
this work provides a new choice for a photoelectrocatalytic reactor
and lays the foundation for the future industrialization of photoelectrocatalytic
CO2 reduction.
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