Multistep Functional Embellishment for p-ZnTe as a Cathode to Boost the Faraday Efficiency of Nitrogen Conversion

An electrochemical N₂ reduction reaction (N₂RR) is a selective sustainable approach to obtain NH₃ at mild conditions and has been proposed as an alternative to the full-blown Haber-Bosch process. However, achieving high yields of NH₃ and high faraday efficiency (FE) at a low overpotential remains a big challenge but has high expectations for the electrocatalytic N₂RR. Herein, a novel p-ZnTe cathode multistep embellished with NiO_x and ZnO thin films was prepared for boosting faraday efficiency to 9.89% for N₂RR at -0.2 V vs reversible hydrogen electrode (RHE), about 12 times of p-ZnTe@ZnO. All components within the NiO_x@p-ZnTe/ZnO electrode work cooperatively. A N source was determined through a ¹⁵N isotopic-labeling experiment. Using steady-state photoluminescence, electrochemical impedance spectroscopy, and control experiments, a possible model of charge transformation is built. In particular, a NiO_x layer has an important impact on increasing interfacial contact between a bare fluorine-doped tin oxide (FTO) glass and p-ZnTe and further reinforcing interfacial electron transfer. This work provides a practical application and a feasible strategy to develop highly efficient catalysts for N₂ reduction and also affords a guideline for the fabrication of a flat electrode.