Efficient Electrocatalytic Nitrate Reduction to Ammonia Based on DNA-Templated Copper Nanoclusters

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic nitrate reduction to ammonia (NO₃RR) in alkaline media is challenging due to limited proton availability on electrode surfaces, hindering reaction kinetics.
• Achieving high rates and selectivity for ammonia synthesis via NO₃RR remains a significant hurdle in sustainable chemistry.

Purpose of the Study:

• To develop a novel catalyst for efficient electrocatalytic nitrate reduction to ammonia in alkaline solutions.
• To investigate the role of single-stranded deoxyribonucleic acid (ssDNA) in enhancing NO₃RR performance.

Main Methods:

• Synthesis of single-stranded deoxyribonucleic acid (ssDNA)-templated copper nanoclusters (CuNCs).
• Electrocatalytic performance evaluation of ssDNA-templated CuNCs for NO₃RR.
• In situ spectroscopy and activation energy studies to elucidate reaction mechanisms.

Main Results:

• ssDNA-templated CuNCs significantly enhanced proton generation on the electrode surface by optimizing interfacial water distribution and hydrogen-bond network connectivity.
• The NO₃RR catalyzed by ssDNA-templated CuNCs followed a reaction pathway similar to that in acidic media, confirmed by activation energy and spectroscopic studies.
• Achieved a high ammonia yield rate of 2.62 mg h^-1 cm^-2 and a Faraday efficiency of 96.8% at -0.6 V vs RHE.

Conclusions:

• ssDNA-templated CuNCs are highly effective electrocatalysts for NO₃RR in alkaline solutions.
• The ssDNA ligand plays a crucial role in facilitating NO₃RR kinetics by enhancing proton availability.
• This work provides a foundation for designing advanced catalyst surface ligands for improved electrocatalytic ammonia synthesis.