Constructing flexible composite electrodes of low crystalline cobalt (Oxy)hydroxides nanosheet grown on carbon fiber cloth via self-reconstruction for electrochemical nitrate-to-ammonia conversion

Electrochemical conversion of NO3−-to NH3 via the nitrate reduction reaction (NO3−RR) is a promising approach for ammonia synthesis and “green hydrogen” storage. Constructing self-supporting and flexible composite electrodes is critical for portable devices of electrochemical conversion of NO3−-to NH3. In this study, carbon fiber cloth is used for a three-dimensional flexible electronic collector, and low-crystalline CoOOH nanosheets (LC-CoOOH NSs) grown on carbon fiber cloth were synthesized by potential induced self-reconstruction of cobalt Prussian blue analogues. The as-prepared self-supporting composite electrode exhibited improved NH3 yield rate. Further investigation revealed that the higher valence state of Co and the lower crystallinity are beneficial for NO3−-to-NH3 conversion. This work shows an example of efficient flexible composite electrode for NO3−-to-NH3 conversion.