Denitrification on PdCu-AC with hydrogen from electrocatalytic water splitting

Highly efficient removal of nitrate from eutrophication water has been attracting great attention. Here, we develop a new-type denitrification system that is capable of catalytic nitrate reduction on denitrification catalysts suspended in the reactor, using hydrogen as reductant directly generated from electrocatalytic hydrogen evolution reaction (HER). To improve system’s efficiency, Ni 3 S 2 nanosheets coated on Ni foam (Ni 3 S 2 -NF) was hydrothermally synthesized and applied as cathode material for HER. Meanwhile, bimetals PdCu nanoparticles dispersed in the channels of activated carbon (PdCu-AC) was also prepared by impregnation method and used as catalysts for nitrate reduction. Under − 1.3 V for HER and using 5%PdCu-AC as catalysts, the denitrification system behaved an optimal nitrate removal, with almost 100% nitrate removal and a dinitrogen selectivity of 64% in 5 h under neutral electrolyte at initial nitrate concentration of 100 mg-N/L. Meanwhile, the catalysts showed satisfactory stability, the system maintained over 95% nitrate removal efficiency and ~ 60% TN removal after 6 times runs at optimal denitrification conditions. Graphic abstract