The Preparation of UiO-66-NH2/CNT Electrocatalyst and its High Catalytic Performance for Electrochemical Synthetic Ammonia in Neutral Electrolyte

Abstract

The electrochemical synthesis of ammonia is a sustainable green ammonia synthesis technology. The core reaction involved in this process-the nitrogen reduction reaction (NRR) is a slow kinetic reaction, which requires efficient catalysts to improve the ammonia yield rate. A series of UiO-66-NH2/CNT-X (X=0.05, 0.10, 0.15, 0.20 g) electrocatalysts with different carbon nanotube (CNT) content were synthesized by hydrothermal method. UiO-66-NH2/CNT-0.15 with appropriate CNT content has the highest NH3 yield of 1.85×10−10 mol cm−2 s−1 (22.644 μg h−1 mgcat−1) at −0.3 V (vs. RHE), and the Faradaic efficiency (FE) is 37.78 %. The main reason is that the conductivity of CNT improves the charge transfer efficiency and ensures the effective electron conduction path of the catalyst. Besides, CNT in UiO-66-NH2/CNT-X composite material inhibits the aggregation of UiO-66-NH2 particles, exposes more active sites and reduces the particle size of UiO-66-NH2. So, the synergistic effect between UiO-66-NH2 particles and CNT improves the ammonia yield.