The low stability and high overpotential defects of Ni can be effectively improved by structural and electronic effects between Ni and another alloying element. In this work, we prepare a series of NiCu alloy film catalysts with different contents by magnetron sputtering to investigate the synergistic effect between Ni and Cu in electrocatalytic hydrogenation of benzaldehyde. The results show that alloying of Ni and Cu can significantly enhance the electrocatalytic activity of benzaldehyde hydrogenation compared to single Ni or Cu. With the increase of Ni content, the conversion rate of benzaldehyde increases two to three orders, and the Faradaic efficiencies of the Ni-rich catalysts are higher than those of the Cu-rich catalysts. The boosted electrocatalytic activity with the increase of Ni content was confirmed by the electrochemical impedance spectra that increasing Ni content can decrease the charge transfer resistance of the alloy catalysts.
Nanoporous copper (np-Cu) has attracted much more attention due to its lower cost compared to other noble metals and high functionality in practical use. Herein, Al
Bi is considered as a highly active and selective electrocatalyst for CO 2 reduction reaction (CO 2 RR), and Sb has great development potential. In this study, we fabricated a series of Bi-Sb alloy films by magnetron co-sputtering and further explored their electrocatalytic performances in CO 2 reduction. In contrast to pure Sb catalyst, the Bi-Sb alloys substantially suppress HER and promote the pathway of CO 2 -to-formate. The formate selectivity increases with the increase of Bi content. When the content of Bi reaches about 40 at%, the Bi-Sb alloy exhibits the highest ability to convert CO 2 to formate, and even shows a higher formate activity than that of pure Bi. Especially, the Bi 45 Sb 55 catalyst exhibits a partial current density of formate formation of 58.0 mA cm −2 and a formate selectivity of 76.7% at −1.0 V vs RHE. A remarkable formate selectivity reaches up to over 95% in the flow cell, and a formate current density of 500 mA cm −2 is achieved at a moderate overpotential of 859 mV, exhibiting great potential for CO 2 RR process to practical applications. The present work could provide guidelines for the design of Bi-Sb alloy catalysts for efficient CO 2 RR.
Ag-Zn alloys are identified as highly active and selective electrocatalysts for CO2 reduction reaction (CO2RR), while how the phase composition of the alloy affects the catalytic performances has not been systematically studied yet. In this study, we fabricated a series of Ag-Zn alloy catalysts by magnetron co-sputtering and further explored their activity and selectivity towards CO2 electroreduction in an aqueous KHCO3 electrolyte. The different Ag-Zn alloys involve one or more phases of Ag, AgZn, Ag5Zn8, AgZn3, and Zn. For all the catalysts, CO is the main product, likely due to the weak CO binding energy on the catalyst surface. The Ag5Zn8 and AgZn3 catalysts show a higher CO selectivity than that of pure Zn due to the synergistic effect of Ag and Zn, while the pure Ag catalyst exhibits the highest CO selectivity. Zn alloying improves the catalytic activity and reaction kinetics of CO2RR, and the AgZn3 catalyst shows the highest apparent electrocatalytic activity. This work found that the activity and selectivity of CO2RR are highly dependent on the element concentrations and phase compositions, which is inspiring to explore Ag-Zn alloy catalysts with promising CO2RR properties.
Electrocatalytic CO2 reduction (CO2R) to multi‐carbon (C2+) products in strong acid presents a promising approach to mitigate the CO2 loss commonly encountered in alkaline and neutral systems. However, this process often suffers from low selectivity for C2+ products due to the competing C1 (e.g., CO and HCOOH) formation and complex C‐C coupling kinetics. In this work, we report a CO2 coverage constraining strategy by diluting CO2 reactant feed to modulate the intermediate distribution and C‐C coupling pathways for an enhanced electrosynthesis of C2+ products in strong acid. Lowering the CO2 feed concentration reduces CO2 coverage on copper catalyst, enriching the surface coverage and optimizing the adsorption configuration of the key CO intermediate for C‐C coupling. This approach efficiently suppresses the formation of undesired C1 products. By employing a 20% CO2 feed, we achieved a significant improvement in C2+ Faradaic efficiency, reaching 68% at 100 mA cm‐2, approximately 1.7 times higher than the 41% obtained using pure CO2. We demonstrated the direct electroreduction of a 30% CO2 feed – representative CO2 concentration of typical industrial flue gases – in a full electrolyzer, achieving a C2+ selectivity of 78% and an energy efficiency of 23% at 200 mA cm‐2.
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