A analysis staff has designed a tandem catalyst to enhance the electroreduction of nitrate into ammonia. By coupling Cu single atom catalysts with adjoining Co3O4 nanosheets, the staff efficiently regulated the adsorption power of intermediates within the nitrate electroreduction course of, selling the synthesis of ammonia.
Their findings are printed in Nature Communications. The staff was led by Prof. Zeng Jie and Prof. Geng Zhigang from the College of Science and Expertise of China (USTC) of the Chinese language Academy of Sciences (CAS).
Changing nitrate (NO3–) from wastewater into ammonia (NH3) not solely provides an efficient method to wastewater remedy but in addition holds promise as a sustainable methodology for ammonia synthesis. Nonetheless, the various adsorption configurations of nitrogen-containing intermediates within the NO3– electroreduction course of pose a problem, making it troublesome for a single catalyst to optimize adsorption concurrently.
Whereas Cu-based electrocatalysts are advantageous for NO3– adsorption, one key concern is the extreme accumulation of nitrite (NO2–) which might consequence within the fast deactivation of catalysts and sluggish kinetics of subsequent hydrogenation steps.
To beat these limitations, the researchers designed a tandem electrocatalyst by combining Cu single atoms anchored on N-doped carbon with adjoining Co3O4 nanosheets (denoted as Co3O4/Cu1-N-C). This modern mixture leverages the strengths of each elements: Cu’s capability to adsorb NO3– and Co3O4‘s capability to adsorb NO2–. This dual-function catalyst goals to optimize the binding energies of intermediates, thereby facilitating the electroreduction course of from NO3– to NH3 extra effectively.
Particularly, the researchers synthesized the Co3O4/Cu1-N-C catalyst by way of a sequence of steps, together with the pyrolysis of Cu-doped ZIF-8 to acquire Cu single atoms on N-doped carbon, adopted by the deposition of Co3O4 nanosheets. The construction and composition of the catalyst had been characterised utilizing numerous methods corresponding to high-angle annular darkish discipline scanning transmission electron microscopy (HAADF-STEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray absorption close to edge construction (XANES) spectroscopy.
These analyses confirmed the profitable mixture of Cu single atoms and Co3O4 nanosheets, in addition to the uniform distribution of the catalytic facilities.
Lastly, efficiency testing of the catalysts was performed in a three-electrode H-type cell, with the focus of NH3 product quantified utilizing the indophenol blue methodology. The check revealed that Co3O4/Cu1-N-C achieved an ammonia manufacturing fee of 114.0 mgNH3h-1cm-2 within the NO3– electroreduction response, which was 2.2 instances and three.6 instances as excessive as that of Cu1-N-C and Co3O4, respectively.
Mechanistic investigations confirmed that Co3O4 successfully regulates the adsorption configuration of NO2– and enhances its binding, thereby accelerating the general electroreduction course of from NO3– to NH3.
This analysis highlights a novel method to addressing the constraints of single catalysts in nitrate electroreduction through the use of a tandem catalyst system. It not solely supplies a deeper understanding of the catalytic mechanisms concerned but in addition units the stage for future developments within the design of superior electrocatalysts for related functions.
Extra info:
Yan Liu et al, Environment friendly tandem electroreduction of nitrate into ammonia by way of coupling Cu single atoms with adjoining Co3O4, Nature Communications (2024). DOI: 10.1038/s41467-024-48035-4
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College of Science and Expertise of China
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Researchers develop environment friendly tandem catalyst to reinforce nitrate electroreduction to ammonia (2024, Could 29)
retrieved 30 Could 2024
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