Hierarchical Ti-supported ZnCoOx nanofilm electrode for long-term continuous and selective electrochemical nitrate-ammonia conversion

초록

Recovering ammonia from nitrate-contaminated water supports circular nitrogen management, yet NO3RR electrodes often trade selectivity for activity and stability. We designed Ti-supported ZnCoOx nanofilm electrodes via electrodeposition/calcination and optimized composition (Co:Zn = 6:0-6:6). The Co:Zn = 6:1.5 electrode minimized charge-transfer resistance and sustained high selectivity. In 0.5 M Na2SO4 containing 1000 mg L-1 NO3-, it removed 94% of NO3--N and achieved 88.8% NH3-N generation (FE 81.9%) in 3 h, with a 0.95 mmol h-1 mg-1 yield rate. A 30 h galvanostatic test showed stable voltage (Delta E = 0.11 V). Performance remained high with NaHCO3 (300 mg L-1) and Cu2+ (1 mg L-1), maintaining FE approximate to 76%. Chloride promoted active chlorine at the anode and lowered NH3 recovery, defining practical windows for robust nitrogen recovery.

키워드