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

在不来梅大学IMSAS研究所和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，它是由配体稳定的。结果表明，这种新型催化材料具有很高的氢传感器应用潜力。可以实现响应时间和稳定性的显著改进。基于该概念的传感器的灵敏度非常高，而使用的催化材料数量很少。该材料由具有催化活性的铂纳米颗粒组成，通过双功能有机配体交联形成多孔网络。传感器芯片采用具有高热隔离性的膜式传感器，其中包含具有高塞贝克系数的热电堆。气体传感器的工作原理是基于对反应热的检测。这项初步工作的结果表明，配体确保粒子保持一定距离。与传统的催化剂相比，配体起到了载体的作用。然而，与非有机载体材料相比，可以实现更高的颗粒密度。与传统催化剂相比，另一个优点是总质量的一小部分。将微传感器方法与配体连接的纳米粒子网络相结合，建立了一种新型催化气体传感器概念的基础。与陶瓷载体相比，纳米颗粒具有显著的优势。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，化学和物理性质仍然是完全未知的。究其原因，到目前为止，双功能配体的检测数量很少，纳米颗粒的尺寸也只有一种。此外，目前的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。为气体传感器装配特殊材料是不可能的。在这个研究项目中，将开发配体连接纳米粒子网络及其应用的基础知识，特别是用于催化气体传感器。系统地研究了配体连接纳米粒子网络用于催化氢传感器的选择性和稳定性。为了实现这一目标，将开发新材料并建造绝热反应堆。该反应器将允许原位光谱研究，并可用作热电微传感器。在催化过程中探索新催化材料的基本机理，通过所获得的知识有针对性地改进所命名的性能。

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.