Boosted ammonium production by single cobalt atom catalysts with high Faradic efficiencies

Abstract

Efficient n = O bond activation is crucial for the catalytic reduction of nitrogen compounds, which is highly affected by the construction of active centers. In this study, n = O bond activation was achieved by a single-atom catalyst (SAC) with phosphorus anchored on a Co active center to form intermediate N -species for further hydrogenation and reduction. Unique phosphorus-doped discontinuous active sites exhibit better n = O activation performance than conventional N -cooperated single-atom sites, with a high Faradic efficiency of 92.0% and a maximum ammonia yield rate of 433.3 μg NH4·h −1 ·cm −2 . This approach of constructing environmental sites through heteroatom modification significantly improves atom efficiency and will guide the design of future functional SACs with wide-ranging applications.

Catalytic reduction of water pollutants: knowledge gaps, lessons learned, and new opportunities

“…Notably, Ru is also used in recent electrochemical systems for NH 3 synthesis from NO 3 − (Li et al, 2020;Chen et al, 2022). Because electrochemical methods do not require a PGM to extract electrons from H 2 , many other electrode materials only contained the first-row transition metals such as Fe, Co, Ni, and Cu (Chen et al, 2020;Wang et al, 2020;Wu et al, 2021;He et al, 2022;Li et al, 2022), which are consistent with the initial findings (Vorlop and Tacke, 1989;Hörold et al, 1993).…”

Conjugated Coordination Polymer as a New Platform for Efficient and Selective Electroreduction of Nitrate into Ammonia

“…Surprisingly, in the electrolytes with low concentration of NO 3 − (10 and 50 × 10 −3 m), the NiO 4 -CCP can obtain a high NH 3 yield rate of 0.82 and 1.65 mmol h −1 mg −1 respectively (Figure 3d; Figure S17, Supporting Information), which outperforms the NiN 4 -CCP and other reported SAC-based NRA catalysts (Figure 3e; Table S3, Supporting Information). [10,14,16,17,[36][37][38][39][40][41][42] Besides, the NiO 4 -CCP catalyst exhibits good durability and recyclability toward NRA. As displayed in Figures S18-S20 (Supporting Information), in the consecutive cycle test for NiO 4 -CCP performed at −0.7 V (vs RHE), the fluctuation of FE and NH 3 yield rate in each cycle is within a reasonable range, indicating its good recyclability toward NRA catalysis.…”

Metal–support interactions for heterogeneous catalysis: mechanisms, characterization techniques and applications

“…Meanwhile, Li et al used the anchoring action of defect-rich carbon substrates to prepare a novel P-modified single-atom Co catalyst (Co-SACs). 145 By modifying Co atoms with P, the asymmetry in the charge distribution and electron redistribution were optimized, which was conducive to activating n O bonds and promoting the formation of nitrogen-containing species in the intermediates. Consequently, the Co-SACs exhibited higher activity for the production of ammonia and excellent cycle stability, Faraday efficiency of up to 92.0%, and the maximum ammonia production rate of 433.3 μg NH 4 h −1 cm −2 , making it have broad application prospect in actual wastewater treatment.…”