Controlled preparation of self-supporting dendritic Cu electrodes and their nitrate electroreduction performance to ammonia

The enrichment of nitrate pollutants in water will bring great harm to ecology and seriously threaten human life and health. It is significant to study the electrocatalytic materials of high efficiency electrocatalytic nitrate reduction to ammonia for ecological protection and formation of the nitrogen cycle. In this study， a self-supporting dendritic Cu/CF （D-Cu/CF） electrode is deposited on the copper foam （CF） skeleton by the hydrogen bubble dynamic template （DHBT）. The orientation tip of the three-dimensional dendrite structure greatly increases the number of active sites and intrinsic activity when it is used in synthesizing ammonia by nitrate electroreduction. The effects of deposition time and different potentials on electrochemical performance are investigated. Under the optimum conditions， D-Cu/CF electrode shows an ammonia production rate of 0.379 mmol·h-1·cm-2 and a Faraday efficiency of 92.8%. The ammonia production rate is stable and the Faraday efficiency is above 90% after 6 cycles of nitrate electroreduction. Furthermore， the D-Cu/CF electrocatalyst exhibits good electroreduction performance in the actual water sample test， showing great potential practical application value.