Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, USA.
Nanoscale. 2017 Sep 14;9(35):12984-12995. doi: 10.1039/c7nr03522e.
Understanding how nano-dimensionality impacts iron oxide based catalysis is central to a wide range of applications. Here, we focus on hematite nanosheets, nanowires and nanoparticles as applied to catalyze the reverse water gas shift (RWGS) probe reaction. We introduce a novel approach to synthesize ultrathin (4-7 nm) hematite nanosheets using copper oxide nanosheets as a hard template and propose a reaction mechanism based on density functional theory (DFT) calculations. Hematite nanowires and nanoparticles were also synthesized and characterized. H temperature programmed reduction (H-TPR) and RWGS reactions were performed to glean insights into the mechanism of CO conversion to CO over the iron oxide nanomaterials and were compared to H binding energy calculations based on density functional theory. While the nanosheets did exhibit high CO conversion, 28% at 510 °C, we found that the iron oxide nanowires had the highest CO conversion, reaching 50% at 750 °C under atmospheric pressure. No products besides CO and HO were detected.
了解纳米尺寸如何影响氧化铁基催化对于广泛的应用至关重要。在这里，我们专注于赤铁矿纳米片、纳米线和纳米颗粒在催化逆水气变换（RWGS）探针反应中的应用。我们采用氧化铜纳米片作为硬模板，提出了一种合成超薄（4-7nm）赤铁矿纳米片的新方法，并基于密度泛函理论（DFT）计算提出了一种反应机制。还合成并表征了赤铁矿纳米线和纳米颗粒。进行了 H 程序升温还原（H-TPR）和 RWGS 反应，以深入了解氧化铁纳米材料上 CO 转化为 CO 的反应机理，并与基于密度泛函理论的 H 结合能计算进行了比较。虽然纳米片确实表现出高的 CO 转化率，在 510°C 时达到 28%，但我们发现氧化铁纳米线在常压下具有最高的 CO 转化率，在 750°C 时达到 50%。除了 CO 和 HO 之外，没有检测到其他产物。
