Effect of water frustration on water oxidation catalysis in the nanoconfined interlayers of layered manganese oxides birnessite and buserite
Effect of water frustration on water oxidation catalysis in the nanoconfined interlayers of layered manganese oxides birnessite and buserite
复制标题
DOI：
10.1039/d0ta09635k
复制
发表时间：
2021-02
影响因子：
--
通讯作者：
Ravneet K. Bhullar;Michael J. Zdilla;M. Klein;Richard C. Remsing
中科院分区：
文献类型：
--
作者：
Ravneet K. Bhullar;Michael J. Zdilla;M. Klein;Richard C. Remsing
水分子的几何挫折的作用，在纳米限制层间的锰氧化物层状材料（水钠锰矿，buserite）的水氧化率检查在一个良好的控制实验。制备水钠锰矿钙，并用于分批合成方案中制备水钠锰矿钙、水钠锰矿钠、水钠锰矿钠和部分脱水的水钠锰矿钠。因此，制备了四种样品，其中控制了影响催化效率的特征（缺陷密度、平均锰氧化态），并且主要差异是夹层的水合程度（水铝锰矿中的两层水对水钠锰矿中的一层水）。分子动力学模拟预测水钠锰矿样品表现出几何水挫折，这有利于氧化还原催化降低马库斯重组能的电子转移，而buserite样品表现出传统的分子间氢键之间的两层aqueous区域，导致较慢的催化行为类似于在散装水的氧化还原反应。利用化学和电化学技术研究了水的氧化活性，证明和量化了水挫折在增强催化作用中的作用。计算和实验结果表明，脱水水钠锰矿的电催化效果最好，水钠锰矿的电催化效果最差，其电催化过电位相差约750 mV，转化数相差约20倍。
The role of geometric frustration of water molecules in the rate of water oxidation in the nanoconfined interlayer of manganese-oxide layered materials (birnessite, buserite) is examined in a well-controlled experiment. Calcium buserite is prepared, and used in a split-batch synthetic protocol to prepare calcium birnessite, sodium buserite, and sodium birnessite, and partially dehydrated sodium birnessite. Thus, four samples are prepared in which features effecting catalytic efficiency (defect density, average manganese oxidation state) are controlled, and the main difference is the degree of hydration of the interlayer (two layers of water in buserites vs. one layer of water in birnessite). Molecular dynamics simulations predict birnessite samples to exhibit geometric water frustration, which facilitates redox catalysis by lowering the Marcus reorganization energy of electron transfer, while buserite samples exhibit traditional intermolecular hydrogen bonding among the two-layer aqeuous region, leading to slower catalytic behavior akin to redox reactions in bulk water. Water oxdiation activity is investigated using chemical and electrochemical techniques, demonstrating and quantifying the role of water frustration in enhancing catalysis. Calculation and experiment demonstrate dehydrated sodium birnessite to be most effective, and calcium buserite the least effective, with a difference in electrocatlytic overpotential of ∼750 mV and a ∼20-fold difference in turnover number.