Linkun Cai, Yuyan Lai, Panchao Yin
Water confined on metal oxide surface plays significant roles in heterogeneous catalysis. Heteropolyacid, a 1.2nm‐metal oxide cluster with well‐defined structure, is applied as a model to understand the dynamics of water on its surface. The surface water strongly associates with heteropolyacid cluster and form the so‐called ‘pseudoliquid phase’ where catalytic reactions are conducted. Broadband dielectric spectroscopy and di?erential scanning calorimetry have been applied to probe the dynamics of water in this pseudoliquid phase. A supercooling phase transition of water below its normal melting temperature and a dipolar glassy relaxation behaviour due to the hindered dynamics of water have been observed. The rich dynamic behavior on the surface of such well‐defined metal clusters provide new perspectives to understand the properties of surface water and their relation to catalytic performance of heteropolyacid.
受限于金属氧化物表面的水在非均相催化中起着重要作用。杂多酸是一种结构明确的1.2 nm金属氧化物簇，非常适合于作为模型来了解水在金属表面的动力学。表面的水与杂多酸分子簇紧密结合，形成所谓的“伪液相”，在其中能够进行各式各样的催化反应。宽频介电谱和差示扫描量热法已被用于探测这种假液相中水的动力学。我们已经能够观察到低于其正常熔化温度的水的过冷相变和由于水的动力学受阻而引起的偶极玻璃态弛豫行为。这类具体明确结构的金属簇表面的丰富动力学行为为了解金属氧化物表面水的性质及其与杂多酸催化性能的关系提供了新的视角。
文章链接：https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cphc.202000832