揭示了NH3氧化对铜基酸催化剂的高N2选择性的起源,通过固体前体表面调制
Tian Tang1, Penghui Ren2, Jingyu Xue1
1Key Laboratory of Low-Grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China; School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China.
使用硫酸盐物种控制金属酸催化剂的酸度和氧化还原点,可以提高NH3氧化选择性. 这种方法稳定了关键的中间体,通过i-SCR机制促进了N2的生产.
科学领域:
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
- 表面化学 表面化学
背景情况:
- 金属酸催化剂在活性和选择性之间表现出"权衡",这是由于异质的酸和氧化还原位所致.
- 这些部位对催化性能的精确分子水平影响,特别是NH3作为前体的影响,仍然不太清楚.
研究的目的:
- 开发一种方法来精确控制金属酸催化剂的酸度和氧化还原特性.
- 阐明表面特征对NH3氧化和选择性催化还原 (SCR) 性能在分子层面的影响.
主要方法:
- 一种简单的分解温度控制方法,使用 (2H+) SO42-物种低于单层分散值.
- 在初始分子动力学 (AIMD) 模拟中研究NH3解离路径.
- 扩散反射红外里埃变换光谱 (DRIFTS) 来确认中间物种.
主要成果:
- 这种 (2H+) SO42-物种精确地调整了活性站点的电子环境和工作功能,控制了酸度和氧化还原特性.
- AIMD模拟显示,即使在500K, (2H+) SO42-也能促进NH3与-NH2中间体的解离,防止过度氧化.
- 漂流证实在高温下丰富的-NH2物种,通过in-situ选择性催化降解 (i-SCR) 机制促进N2选择性.
结论:
- 一种新的分解温度控制方法有效调节金属酸催化剂的特性.
- 稳定的-NH2中间体对于通过i-SCR途径在NH3氧化中高N2选择性至关重要.
- 这种方法通过操纵表面的酸和氧化还原功能来精确控制催化性能.
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