通过Cu-ZSM-5合成甲醇中反应性中间体的氧前体
Pieter J Smeets1, Ryan G Hadt, Julia S Woertink
1Department of Chemistry, Stanford University, Stanford, California 94305, USA.
Journal of the American Chemical Society
|October 7, 2010
概括
研究人员确定了一种氧二铜 (II) 物种[Cu2O2+]作为Cu-ZSM-5催化剂上的甲氧化中的活性位点的氧前体.
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
- 无机化学 无机化学 有机化学
背景情况:
- 将甲选择性氧化成甲醇对于化学合成至关重要.
- -ZSM-5热质是这种转变的关键催化剂.
- 活跃氧化物种的确切性质尚不清楚.
研究的目的:
- 在Cu-ZSM-5中识别Cu-ZSM-5中反应性单-μ-oxo) 二铜 (II) 种 ([Cu(2) O](2+)) 的氧前体.
- 阐明甲氧化过程中活性位形成的机制.
主要方法:
- 紫外线吸收光谱检测前体物种.
- 共振拉曼 (rR) 光谱法,使用 (18) O (((2) 同位素标记来描述振动.
- 使用 (18) O ((2) 追踪氧气的吸收,进行温度编程消化 (TPD).
主要成果:
- 一种双铜 (II) 过氧物种,[Cu (II) ] (O (II) ] (O (II) ]) [Cu (II) ] (O (II) ] (O (II) ]) [Cu (II) ] (O (II) ] (O (II) ]) [Cu (II) ] (O (II) ] (O (II) ]) [Cu (II) ] (O (II) ] (O (II) ] (O (II) ]) [Cu (II) ] (O (II) ] (O (II) ] (O (II) [Cu (II) ] (O (II) ]) [Cu (II) ] (O (II) ] (O (II) ] (O (II) ] (O (II) ] (O (II) [Cu (II) ] (O (II) ] (O (II) ] (O (II) ] (O (II)) 的吸收带在29,000厘米 (-1) 的被确定为O (II) 的前体.
- rR光谱证实了过氧性质,并确定了O-O和Cu-Cu键的振动.
- (18)O(2) TPD揭示了第二个氧原子在转化为[Cu(2) O](2+) 的过程中被纳入热石网格.
结论:
- [Cu(2)(O(2)) ](2+) 种直接转化为活跃的[Cu(2) O](2+) 位点.
- 观众Cu(+) 位提供电子来裂开过氧键.
- 本研究定义了Cu-ZSM-5催化剂中氧活性位形成的机制.
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