A Cu loaded NiFe layered double hydroxide bifunctional electrocatalyst with a coupled interface structure for both the nitrate reduction reaction and oxygen evolution reaction

Abstract

The development of efficient electrochemical nitrate reduction reaction (NO₃⁻RR) for ammonia production (NH₃) and water splitting reaction for the oxygen evolution reaction (OER) is of great significance for alleviating the growing energy demand and environmental pollution. In this contribution, copper nanocluster-loaded nickel iron layered double hydroxide (Cu/NiFe LDH) nanosheets are demonstrated to be efficient non-noble bifunctional electrodes for both the NO₃⁻RR and OER, wherein, Cu is uniformly distributed on the surface of NiFe LDH to form a coupled interface structure with surface oxygen groups, forming optimized active sites. Theoretical analysis and test results indicate the enhanced performance benefitting from the coupled interface characteristics. For the NO₃⁻RR, the presence of Cu changed the distribution of electrons, thereby accelerating the desorption of NH₃ to continue the reaction. For the OER, Cu nanoclusters were evenly distributed on the surface, which not only facilitated electron transport but also protected NiFe LDH, thus improving activity and durability. Ultimately, Cu/NiFe LDH is an excellent bifunctional electrocatalyst for the NO₃⁻RR and OER, which also provides new insights for other related applications.