Self-supported porous copper oxide nanosheet arrays for efficient and selective electrochemical conversion of nitrate ions to nitrogen gas

Abstract

• Porous copper oxide nanosheets grow in situ on nickel foam surface (NF). • Removes low-concentration nitrate rapidly with almost no production. • CuO/NF exhibits excellent stability and N 2 selectivity in nitrate reduction. Electrochemical techniques have shown advantages for the removal of low-concentration nitrate. Here, copper oxide nanosheets were grown on self-supporting nickel foam (NF) to prepare electrodes (CuO/NF), which realized the rapid and highly selective conversion of nitrate pollutants in sewage into non-toxic and harmless N 2 . The CuO/NF afforded 100% NO 3 – removal within 100 min and 99.53% selectivity for N 2 at –50 mA without producing a lot of by-products (NO 2 – , NH 4 + , and N 2 H 4 ). Furthermore, 81.8% of NO 3 – was removed under the given conditions after six experimental repetitions. These results suggest that the catalyst has excellent electrochemical stability. The performance of CuO/NF for the electrocatalytic removal of NO 3 – in simulated wastewater (which contained Cl – and SO 4 2– ) was almost unaffected. Because of the high efficiency, high stability, and low cost of CuO/NF, this catalyst is practical for the removal of nitrate for wastewater purification. Copper oxide nanosheets grown on nickel foam realizes rapid, selective and efficient conversion of nitrate in water.