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首页> 外文期刊>RSC Advances >A Pd nanocatalyst supported on multifaceted mesoporous silica with enhanced activity and stability for glycerol electrooxidation
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A Pd nanocatalyst supported on multifaceted mesoporous silica with enhanced activity and stability for glycerol electrooxidation

机译：负载在多孔介孔二氧化硅上的Pd纳米催化剂具有增强的活性和对甘油电氧化的稳定性

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Glycerol is massively produced as a byproduct of biodiesel manufacturing, which decreases its price and increases its inadequate disposal. The use of glycerol to feed anodes of alkaline fuel cells and electrolysers has emerged as potential alternatives for its use. However, the activity and stability of commercial Pd/C nanoparticles currently proposed do not reach the required performance. Here, we propose a new Pd catalyst deposited in mesoporous silica (SiO2) with enhanced activity and stability for glycerol electrooxidation in alkaline media. We synthesized well-ordered mesoporous silica with pores in the form of a fountain pen and lmm symmetry, in a cage-like arrangement. Such a structure was proved by experiments of microscopy, X-ray diffraction, N2 isotherms and small-angle X-ray scattering measured in synchrotron light. Next, we produced patterned Pd/SiO2 in a one-step synthesis and ordered Pd after template removal. The Pd catalysts were characterized by microscopy, dispersive X-ray spectrometry and X-ray diffraction. Pd/SiO2 and Pd showed improved current density and stability compared to Pd/C. The current density of Pd/SiO2 reached twice the values found for Pd/C. The enhancement is understood as a multiple role of the mesoporous silica support, which works as a seed mediator to order the Pd nanoparticles and mainly as a trap that confines the reactant inside the mesoporous structure, increasing the frequency of collision with active Pd sites. Furthermore, we showed that no carbonyl or intact glycerol was found on Pd/SiO2 after exhaustive cycles of use, except for adsorbed CO that was quickly removed from the surface, which is a probable reason for an improved pathway of glycerol electrooxidation via CO.
机译：甘油作为生物柴油生产的副产品而大量生产，这降低了其价格并增加了不足的处置量。使用甘油来供给碱性燃料电池和电解槽的阳极已经成为其使用的潜在替代品。然而，当前提出的商业Pd / C纳米颗粒的活性和稳定性未达到所需的性能。在这里，我们提出了一种新型的钯催化剂，该催化剂沉积在介孔二氧化硅（SiO 2 ）中，具有增强的活性和在碱性介质中对甘油电氧化的稳定性。我们合成了有序的介孔二氧化硅，其孔形为钢笔，呈 lm m 对称，呈笼状排列。通过显微镜，X射线衍射，N 2 等温线和在同步加速器光下测得的小角度X射线散射证明了这种结构。接下来，我们一步合成合成图案化的Pd / SiO 2 ，并在去除模板后对Pd进行排序。通过显微镜，色散X射线光谱法和X射线衍射对Pd催化剂进行了表征。与Pd / C相比，Pd / SiO 2 和Pd显示出更高的电流密度和稳定性。 Pd / SiO 2 的电流密度达到Pd / C的两倍。增强被理解为介孔二氧化硅载体的多重作用，其充当种子介体以使Pd纳米粒子有序，并且主要用作将反应物限制在介孔结构内部的陷阱，从而增加了与活性Pd位点碰撞的频率。此外，我们显示，在使用彻底后，在Pd / SiO 2 上未发现羰基或完整甘油，只是吸附的CO可以从表面快速去除，是通过CO改善甘油电氧化途径的可能原因。

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