Au-modified Cu2O nanocubes for light-enhanced nitrate electroreduction to ammonia

As an alternative to the traditional ammonia (NH3) synthesis method, the electrochemical reduction reaction of nitrate (NO3-RR) for NH3 production not only mitigates nitrate pollution but also yields economically valuable NH3. Cu2O nanomaterials exhibit excellent catalytic activity for NO3-RR with low cost and are beneficial for the rate-limiting step (NO3- to NO2-). In this work, Au-modified Cu2O nanocubes (Au/Cu2O NCs) were synthesized and used as an efficient NO3-RR electrocatalyst for NH3 production. At -0.75 V potential (relative to the reversible hydrogen electrode, RHE), Au/Cu2O NCs reach 39.79 mg h(-1) mg(cat)(-1) in NH3 yield and a faradaic efficiency of 92.93%. Furthermore, the localized surface plasmon resonance (LSPR) characteristics of Au and a narrow band gap of Cu2O can generate plasma and photoexcited electrons, which can efficiently utilize visible light to accelerate NO3-RR. Indeed, the synergistic effect between Au and Cu2O can result in an increased NH3 yield of 57.3 mg h(-1) mg(cat)(-1) under external light conditions for NO3-RR, 1.44 times higher than that without light.