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<p>Herein, Ag/TiO<sub>2</sub> catalysts modified with Cu, Ce, Mn, and Co were synthesized via impregnation and vacuum rotary evaporation for low-temperature NH<sub>3</sub> selective catalytic oxidation (NH<sub>3</sub>-SCO). Among all the modified samples, Ag–Cu/TiO<sub>2</sub> with an optimal Ag/Cu molar ratio of 0.25 exhibited exceptional performance, achieving &gt; 85% NH3 conversion and &gt; 90% N<sub>2</sub> selectivity at 175&#xa0;°C. The superior activity and selectivity of Ag–Cu/TiO₂ were attributed to its uniform Ag dispersion, enhanced NH<sub>3</sub> adsorption capacity (by NH<sub>3</sub>-TPD), and abundant Brønsted acidic sites. In contrast, Mn doping significantly improved low-temperature activity (50% NH<sub>3</sub> conversion at 150&#xa0;°C) but induced over-oxidation, generating 50% N<sub>2</sub>O and NO<sub><i>x</i></sub> by-products due to the strong redox properties of Mn. Mechanistic studies via in-situ DRIFTS and XPS demonstrated that Cu modification optimized electron transfer between Ag and TiO<sub>2</sub>, while H<sub>2</sub>-TPR revealed Cu–Ag synergy reduced the reduction temperature of Ag<sub>2</sub>O species. This work provides a strategic framework for designing efficient NH<sub>3</sub>-SCO catalysts by balancing metal synergy and redox-activity modulation.</p> Graphical abstract <p></p>

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Study on the effect of metal synergy on Ag/TiO2 catalyst for low-temperature selective catalytic oxidation of ammonia

  • 期刊论文

  • 发表日期：

    2025年6月4日

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  • Bin Guan,
  • Junyan Chen,
  • Zhongqi Zhuang,
  • Lei Zhu,
  • Zeren Ma,
  • Xuehan Hu,
  • Chenyu Zhu,
  • Sikai Zhao,
  • Kaiyou Shu,
  • Hongtao Dang,
  • Junjie Gao,
  • Luyang Zhang,
  • Tiankui Zhu,
  • Zhen Huang

摘要

Herein, Ag/TiO2 catalysts modified with Cu, Ce, Mn, and Co were synthesized via impregnation and vacuum rotary evaporation for low-temperature NH3 selective catalytic oxidation (NH3-SCO). Among all the modified samples, Ag–Cu/TiO2 with an optimal Ag/Cu molar ratio of 0.25 exhibited exceptional performance, achieving > 85% NH3 conversion and > 90% N2 selectivity at 175 °C. The superior activity and selectivity of Ag–Cu/TiO₂ were attributed to its uniform Ag dispersion, enhanced NH3 adsorption capacity (by NH3-TPD), and abundant Brønsted acidic sites. In contrast, Mn doping significantly improved low-temperature activity (50% NH3 conversion at 150 °C) but induced over-oxidation, generating 50% N2O and NOx by-products due to the strong redox properties of Mn. Mechanistic studies via in-situ DRIFTS and XPS demonstrated that Cu modification optimized electron transfer between Ag and TiO2, while H2-TPR revealed Cu–Ag synergy reduced the reduction temperature of Ag2O species. This work provides a strategic framework for designing efficient NH3-SCO catalysts by balancing metal synergy and redox-activity modulation.

Graphical abstract