催化作用
纳米颗粒
法拉第效率
氨
选择性
电解
电化学
硝酸盐
材料科学
X射线光电子能谱
化学工程
无机化学
化学
纳米技术
电极
有机化学
物理化学
工程类
电解质
作者
Eamonn Murphy,Baiyu Sun,Martina Rüscher,Yuanchao Liu,Wenjie Zang,Shengyuan Guo,Uta Hejral,Ying Huang,Alvin Ly,Iryna V. Zenyuk,Xiaoqing Pan,Janis Timoshenko,Beatriz Roldán Cuenya,Erik David Spoerke,Plamen Atanassov
标识
DOI:10.26434/chemrxiv-2023-x25jj
摘要
The electrochemical reduction of oxidized nitrogen species enables a pathway for the carbon neutral synthesis of ammonia (NH3). The most oxidized form of nitrogen, nitrate (NO3-) can be reduced to NH3 via the nitrate reduction reaction (NO3RR), which has been demonstrated at high selectivity. However, to make NH3 synthesis cost-competitive with current technologies, high NH3 partial current densities (jNH3) must be achieved to reduce the levelized cost of NH3. Here, we leverage the high NO3RR activity of Fe-based materials to synthesize a novel active particle-active support system with Fe2O3 nanoparticles supported on atomically dispersed Fe-N-C. By synergizing the activity of both nanoparticles and single atom sites, the optimized 3xFe2O3/Fe-N-C catalyst demonstrates an ultrahigh NO3RR activity, reaching a maximum jNH3 of 1.95 A cm-2 at a Faradaic efficiency (FE) for NH3 of 100% and an NH3 yield rate over 9 mmol hr-1 cm-2. Operando XANES and post-mortem XPS reveal the importance of a pre-reduction activation step, reducing the surface Fe2O3 (Fe3+) to highly active Fe0 sites, which are maintained during electrolysis, to realize the ultrahigh NO3RR activity. Durability studies demonstrate the robustness of both the Fe2O3 particles and Fe-Nx sites at highly cathodic potentials, maintaining a current of -1.3 A cm-2 over 24 hours, a near unity FENH3. This work exhibits an effective and durable active particle-active support system enhancing the performance of the NO3RR, enabling industrially relevant current densities and near 100% selectivity.
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