Recently, Professor Guan Bo'ou's team from the School of Physics and Optoelectronic Engineering at Jinan University, with the support of projects such as the National Natural Science Foundation, has designed a fiber-optic-based photocatalytic sensor for real-time, in-situ analysis of reactant concentrations and thermal effects on catalyst surfaces during photoelectrocatalysis processes. Their findings have been published in "Advanced Science."
Photocatalysis technology enables the conversion of solar energy to chemical energy under mild conditions without generating secondary pollution, making it an important approach to addressing current environmental and energy challenges. During catalysis, changes in reactant concentrations on catalyst surfaces and the generation of thermal effects are two key parameters that characterize catalytic efficiency and explain reaction mechanisms. These parameters govern the macroscopic reactions of catalysts and have a significant impact on the evaluation of the structure-performance relationship within catalysts. To understand the mechanisms of photocatalysis and further enhance catalytic performance, it is crucial to extend the observation of macroscopic catalytic performance to the monitoring and analysis of reactant concentrations and temperature changes on the submicron scale of catalyst surfaces. However, this work is highly challenging.
Numerous efforts have been made to find new characterization techniques to provide information on reaction products during catalytic decomposition processes. These methods include gas chromatography-mass spectrometry, UV-visible absorption spectroscopy, and Raman spectroscopy. Additionally, thermocouples, scanning thermal microscopes, and infrared thermal imagers have been used to monitor catalyst temperatures. However, these methods often require large, expensive instruments and complex operations. Furthermore, they mainly focus on macroscopic reaction outcomes and lack the capability for real-time monitoring on the submicron scale.
In response to the challenges faced in monitoring key parameters in photocatalytic reactions, Professor Guan Bo'ou's team utilized microfibers as carriers. By orderly assembling catalysts and pollutants on the fiber surface, they constructed a "laboratory-on-fiber" for photocatalysis. They replaced the light source that excites catalytic reactions with a pump laser coupled into the fiber, enabling the fiber's evanescent field to stimulate the photocatalytic effect on the fiber surface, simulating the photocatalytic reaction process. Due to the rapid response capability and submicron-scale penetration depth of the fiber's evanescent field, the fiber can sense the reaction processes on the surface of the "fiber-on-lab" and achieve real-time monitoring of the two key parameters of reactant concentrations and thermal effects on catalyst surfaces in catalytic reactions. Through the monitoring of the photocatalytic sensor based on microfibers, the research team obtained a stable correlation between real-time parameters and catalytic activity, providing an important foundation for understanding catalytic processes and mechanisms.
This method is expected to fill a significant gap in existing monitoring methods for catalytic processes and heat generation.
Related Paper Information: https://doi.org/10.1002/advs.202310264
Using photocatalytic microfiber "FiberLab" for in-situ monitoring of changes in reactant concentration and heat generation on catalyst surfaces. Image provided by the research team.
