Details

Autor(en) / Beteiligte

• Zhang, Shengbo
• Zha, Yuankang
• Ye, Yixing
• Li, Ke
• Lin, Yue
• Zheng, Lirong
• Wang, Guozhong
• Zhang, Yunxia
• Yin, Huajie
• Shi, Tongfei
• Zhang, Haimin

Titel

Oxygen-Coordinated Single Mn Sites for Efficient Electrocatalytic Nitrate Reduction to Ammonia

Ist Teil von

• Nano-micro letters, 2024-12, Vol.16 (1), p.9-9, Article 9

Ort / Verlag

Singapore: Springer Nature Singapore

Erscheinungsjahr

2024

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Highlights Oxygen-coordinated single-atom Mn catalyst was fabricated via introducing oxygen functional groups rich bacterial cellulose as the adsorption regulator through a combined impregnation–pyrolysis–etching synthetic route. Mn–O–C as the electrocatalyst exhibits superior electrocatalytic activity toward ammonia synthesis with a maximum NH 3 yield rate of 1476.9 ± 62.6 μg h − 1  cm − 2 at − 0.7 V (vs. RHE) and a faradaic efficiency of 89.0 ± 3.8% at − 0.5 V (vs. RHE) under ambient conditions. Electrocatalytic mechanism of Mn–(O–C 2 ) 4 site for nitrate reduction reaction is unveiled by a combination of in situ spectroscopy characterization and computational study. Electrocatalytic nitrate reduction reaction has attracted increasing attention due to its goal of low carbon emission and environmental protection. Here, we report an efficient NitRR catalyst composed of single Mn sites with atomically dispersed oxygen (O) coordination on bacterial cellulose-converted graphitic carbon (Mn–O–C). Evidence of the atomically dispersed Mn–(O–C 2 ) 4 moieties embedding in the exposed basal plane of carbon surface is confirmed by X-ray absorption spectroscopy. As a result, the as-synthesized Mn–O–C catalyst exhibits superior NitRR activity with an NH 3 yield rate (R NH3 ) of 1476.9 ± 62.6 μg h − 1 cm − 2 at − 0.7 V (vs. reversible hydrogen electrode, RHE) and a faradaic efficiency (FE) of 89.0 ± 3.8% at − 0.5 V (vs. RHE) under ambient conditions. Further, when evaluated with a practical flow cell, Mn–O–C shows a high R NH3 of 3706.7 ± 552.0 μg h − 1 cm − 2 at a current density of 100 mA cm − 2 , 2.5 times of that in the H cell. The in situ FT-IR and Raman spectroscopic studies combined with theoretical calculations indicate that the Mn–(O–C 2 ) 4 sites not only effectively inhibit the competitive hydrogen evolution reaction, but also greatly promote the adsorption and activation of nitrate (NO 3 − ), thus boosting both the FE and selectivity of NH 3 over Mn–(O–C 2 ) 4 sites.