DOI: 10.1002/smll.76312 ISSN: 1613-6810
CO
2
Laser‐Synthesized NiCoCu Borate Enables Efficient Nitrate‐to‐Ammonia Electrosynthesis and Durable Zinc–Nitrate Batteries
Jayesh Cherusseri, Nivarthi Rajiv Bharadwaj, Pimjai Pimbaotham, Chae Eun Park, Siriporn Jungsuttiwong, Myong Yong Choi ABSTRACT
The electrocatalytic NO
3
−
reduction reaction (eNO
3
RR) is a facile and green method for the generation of electricity with the simultaneous production of NH
3
. Herein, we report the synthesis of hierarchical nickel–cobalt–copper borate ((Ni
1/3
Co
1/3
Cu
1/3
)
3
B
2
O
6
) nanosheets via a carbon dioxide (CO
2
) laser irradiation method and investigate their eNO
3
RR performance in a 1
m
KOH electrolyte containing 0.1
m
KNO
3
. Initially, (Ni
1/3
Co
1/3
Cu
1/3
)
3
B
2
O
6
is synthesized via CO
2
laser irradiation within a short processing period of 1 min, where this method enables a rapid material synthesis compared with conventional methods, such as hydrothermal, solvothermal, and wet‐chemical approaches. The (Ni
1/3
Co
1/3
Cu
1/3
)
3
B
2
O
6
catalyst achieves a maximum NH
3
yield rate of 4.1 mg h
−1
cm
−2
and a Faradaic efficiency of 90.69% at −0.3 V vs. the reversible hydrogen electrode. In‐depth analysis of eNO
3
RR kinetics using in situ Raman, ex situ X‐ray diffraction, and ex situ Fourier transform infrared spectroscopy reveals information on the reaction intermediates and reaction pathways involved. Extended density functional theory calculations further corroborate the experimental findings related to reaction intermediates and pathways during the eNO
3
RR. A zinc (Zn)–NO
3
−
battery assembled using (Ni
1/3
Co
1/3
Cu
1/3
)
3
B
2
O
6
as the cathode and a Zn plate as the anode exhibits an open‐circuit voltage of 1.44 V at 12 mA cm
−2
.