Ligand-Linked Platinum Nanoparticles: A new Material for gas sensors with high potential

在不莱梅大学IMSAS和IAPC研究所的合作下，开发了一种催化微型气体传感器的新概念。这个概念是基于铂纳米粒子，这是稳定的配体。表明了这种新型催化材料在氢传感器中的巨大潜力。可以实现响应时间和稳定性的显著改善。基于该概念的传感器的灵敏度非常高，其中使用少量的催化材料。这些材料由具有催化活性的铂纳米颗粒组成，这些纳米颗粒通过双官能有机配体交联形成多孔网络。作为传感器芯片，使用具有高隔热性的膜传感器，其包含具有高塞贝克系数的热电堆。气体传感器的原理是基于对反应热的检测。这项初步工作的结果表明，配体确保了粒子保持一定的距离。与常规催化剂相比，配体充当载体。然而，可以实现与非有机载体材料相比更高的颗粒密度。另一个优点是与常规催化剂相比，总质量的一小部分。通过将微传感器方法与配体连接的纳米颗粒网络相结合，开发了一种新型催化气体传感器概念的基础。与纳米颗粒的陶瓷载体相比，可以显示出显著的优点。用配体连接的催化纳米颗粒网络可以取得的初步成功是很高的。然而，其化学和物理性质仍然完全未知。原因是到目前为止，只有少量的双功能配体被检测，以及只有一种尺寸的纳米颗粒。此外，电流传感器设计不提供材料的后表征或原位表征。因此，配体连接的催化纳米颗粒的全部潜力仍然是完全未知的。气体传感器的特殊材料的组装是不可能的。在这个研究项目中，将开发配体连接的纳米颗粒网络及其应用的基础知识，特别是用于催化气体传感器。本文将系统地研究配体连接纳米粒子网络催化氢传感器的选择性和稳定性。为了实现这一意图，将开发新材料并建造绝热反应器。该反应器将允许原位光谱研究，并可用作热电微传感器。将在催化过程中探索新催化材料的基本机理，以便通过所获得的知识具体改善指定的性能。

In cooperation of the Institutes IMSAS and IAPC from the University of Bremen, a novel concept for catalytic micro gas sensors has been developed. The concept is based on platinum nanoparticles, which are stabilized by ligands. The high potential of the new catalytic material for hydrogen sensors was shown. A significant improvement of response time and of stability can be achieved. The sensitivity of the sensor based on the concept is very high, whereat low quantities of catalytic material are used. The materials consist of catalytically active platinum nanoparticles which are cross linked by bifunctional organic ligands to form a porous network. As a sensor chip, a membrane sensor with high thermal isolation is used, which contains thermopiles with a high Seebeck coefficient. The principle of the gas sensor is based on detection of heat of reaction. The results of this preliminary work have shown that the ligands ensure that the particles are kept at distance. The ligands act as a carrier, compared to a conventional catalyst. However, higher particle densities compared to non-organic carrier materials can be achieved. A further advantage is the small part of the total mass compared to conventional catalysts. The foundation of a new type of catalytic gas sensor concept has been developed by combining the micro-sensor approach with ligand-linked nanoparticle networks. Significant advantages compared to ceramic carriers for nanoparticles could be shown. The initial success that could be achieved with ligand-linked networks of catalytic nanoparticles is high. However, the chemical and physical properties are still completely unknown. The reasons are that up to now, only a small quantity of bifunctional ligands was examined, as well as only one size of nanoparticles. Furthermore, the current sensor design does not offer a post characterization or an insitu characterization of the materials. Therefore, the full potential of ligand-linked catalytic nanoparticles is still completely unknown. The assembling of special materials for gas sensors is not possible. Within this research project, a fundamental knowledge of ligand-linked nanoparticle networks and their application will be developed, especially for catalytic gas sensors. The selectivity and stability of ligand-linked nanoparticle networks for catalytic hydrogen sensors will be investigated systematically. To achieve this intention, new materials will be developed and an adiabatic reactor will be built. This reactor will allow insitu spectroscopic studies and can be used as a thermoelectric microsensor. The basic mechanisms of the new catalytic material will be explored during catalysis, in order to specifically improve the named properties through the obtained knowledge.