Coupling iron oxide with iron single-atom catalyst promotes neutral electrochemical nitrate reduction from water
Jinshan Wei, Xihui Lu, Hexing Lin, Shaoqing Liu, Xiaoxiao Wei, Meng Sun, Gang Liu, Chengzhi Hu, Liangjie Wang, Huazhang Zhao, Yayun Li
Abstract
Electrochemical nitrate reduction reaction (NO 3 RR) presents a promising approach for sustainable water denitrification. Yet its practical implementation is hindered by sluggish reaction kinetics. Herein, we develop a dual-functional catalyst comprising carbon-wrapped Fe 3 O 4 nanoparticles integrated with Fe single atom sites (FeNC-Fe 3 O 4 ) as, which demonstrates exceptional activity and stability for NO 3 RR. The FeNC-Fe 3 O 4 achieves a Faradic efficiency of 95.63% and an NH 3 yield of 2.95 mg cm -2 h -1 at -0.6 V vs. RHE in a neutral electrolyte. Mechanistic investigations, including in situ analysis and density functional theory calculations, reveal that the synergetic interplay between FeNC and Fe 3 O 4 nanoparticles and the enlargement on double-layer capacitance, reduces the energy barrier for key intermediates, and provides abundant active sites for NO 3 RR. Furthermore, the catalyst exhibits an 85.1% nitrate conversion efficiency and 87.2% N 2 selectivity at -0.6 V vs. RHE, where Cl - play a crucial role in promoting the N 2 generation. This work underscores the potential of integrating Fe 3 O 4 with FeNC to advance the practical utility of single atom catalysts, offering a design paradigm for advanced metal oxide hybrid catalysts.