High-Performance Electrochemical Nitrate Reduction to Ammonia under Ambient Conditions Using a FeOOH Nanorod Catalyst
Qin Liu, Qian Liu, Lisi Xie, Yuyao Ji, Tingshuai Li, Bing Zhang, Na Li, Bo Tang, Yang Liu, Shuyan Gao, Yonglan Luo, Lingmin Yu, Qingquan Kong, Xuping Sun
Abstract
Electrocatalytic nitrate reduction is promising as an environmentally friendly process to produce high value-added ammonia with simultaneous removal of nitrate, a widespread nitrogen pollutant, for water treatment; however, efficient electrocatalysts with high selectivity are required for ammonia formation. In this work, FeOOH nanorod with intrinsic oxygen vacancy supported on carbon paper (FeOOH/CP) is proposed as a high-performance electrocatalyst for converting nitrate to ammonia at room temperature. When operated in a 0.1 M phosphate-buffered saline (PBS) solution with 0.1 M NaNO3, FeOOH/CP is able to obtain a large NH3 yield of 2419 μg h–1 cm–2 and a surprisingly high Faradic efficiency of 92% with excellent stability. Density functional theory calculation demonstrates that the potential-determining step for nitrate reduction over FeOOH (200) is *NO2H + H+ + e– → *NO + H2O.