Nanoflower‐Like CuPd/CuO Heterostructure for an Energy‐Output Electrocatalytic System Coupling Ammonia Electrosynthesis and Zinc‐Nitrate Battery
Jingsha Li, Lvfei Liu, Shunyuan Huang, Haiyan Wang, Yougen Tang, Chunmei Zhang, Feng Du, Ruguang Ma, Chang Ming Li, Chunxian Guo
Abstract
Abstract Electrochemical nitrate reduction reaction (NO 3 RR) can effectively alleviate nitrate pollution and simultaneously realize ammonia electrosynthesis at room temperature. However, it remains a significant challenge for NO 3 RR to achieve high Faradic efficiency in a full concentration range. Herein, nanoflower‐like copper‐palladium alloy/CuO heterostructure (CuPd/CuO@NF) is successfully fabricated by the hydrothermal synthesis of CuO nanoflowers and subsequent formation of CuPd alloy. The as‐obtained CuPd/CuO@NF exhibits remarkable electrochemical performance for NO 3 RR in the NO 3 − ‐N range from 20 to 1400 ppm, especially with NO 3 − conversion rate of 97.8% and NH 3 selectivity of 99.3% at 20 ppm, Faradic efficiency of 94.2% and NH 3 yield rate of 1.37 mmol h −1 cm −2 at 1400 ppm. In‐situ Fourier transform infrared spectroscopy and Raman spectra reveal that CuPd/CuO@NF first catalyzes NO 3 − reduction to NO 2 − , which is rapidly reduced to NH 3 by forming *NH, *NH 2 , and *NH 2 OH intermediates. Density functional theory calculations suggest that the NHO route is thermodynamically favorable. When CuPd/CuO@NF is applied in zinc‐nitrate battery, it demonstrates a maximum power density of 53.7 mW cm −2 , with NO 3 − conversion of 99.9% and Faradic efficiency of 94.4%. This work offers valuable insights into the design of novel NO 3 RR electrocatalysts and zinc‐nitrate batteries.