Planar Chlorination Engineering Enhances the Polarity of the Fe–N<sub>4</sub> Site for Boosting Nitrate Electroreduction
Ziyi Wang, Xin Lian, Rongyan Yang, Xiaomeng Guo, Shengjie Wei, Jijie Zhang, Xian‐He Bu
Abstract
Introducing polarity in traditional metal-N 4 catalytic sites and strengthening the adsorption of polar NO 2 * intermediate are advantageous for the deep reduction of nitrate into ammonia. Herein, the planar chlorination engineering strategy successfully introduced the C–Cl bonds adjacent to the Fe–N 4 catalytic site with higher polarity, effectively boosting the catalytic activity for the nitrate reduction reaction (NO 3 RR). The maximal NH 3 yield rate and the corresponding turnover frequency (TOF) value catalyzed by the Fe–N 4 /CNCl catalyst were 1.82 mg h –1 cm –2 and 245 h –1 at −0.83 V vs RHE, which were 3.4 times and 2.7 times those of the traditional Fe–N 4 /CN catalyst without polarity, respectively. The Fe–N 4 /CNCl catalyst also exhibited satisfactory stability during consecutive 15 cycles. The density functional theory (DFT) calculation revealed that the planar chlorination engineering of the Fe–N 4 site with higher polarity strengthened the adsorption of polar NO 2 * intermediate, facilitated the deep reduction of nitrate into ammonia, lowered the energy barrier of rate-determining step (RDS) and thus improved the catalytic activity. This work exhibited the enormous advantage of a planar chlorination engineering strategy for enhancing the activity of electrocatalysis by introducing polarity in the traditional metal-N 4 catalytic site.