Session: 06-02 Materials and Fundamentals

Paper Number: 115116

115116 - The Role of Plasmonic Photocatalysts in Sunlight-Powered Sabatier and Reverse Water Gas Shift Processes 

Plasmonic photocatalysis has emerged as a new frontier to facilitate sunlight-powered chemical conversions under milder conditions than conventional thermal catalysis. However, accurately distinguishing thermal from non-thermal contributions in plasmonic photocatalysis has long been subject to controversy, and clarifying this point is of importance to exploit the full potential of plasmonic photocatalysis. One challenge lies in the precise measurement of the locally resolved, 3D temperature profile across the thin catalyst packed bed under illuminating conditions that requires innovative solution beyond thermal imaging and local measurements with thermocouples. Another challenge lies in performing control experiments to achieve exactly the same temperature profile between illuminating and dark conditions in order to isolate the thermal effect. Here, we demonstrate that the two challenges can be overcome by combining advanced experimental and computational techniques, and the role of plasmonic photocatalysts is revealed for two distinct processes: the exothermic Sabatier reaction (yielding CH₄) and the endothermic reverse water gas shift reaction (yielding CO). Accurate 3D, in operando temperature measurements of the illuminated catalyst bed is achieved using a tailored optical sensor based on fiber Bragg gratings with high spatiotemporal resolution. To completely isolate the thermal effect, parameter-free multiphysics simulation serves as a predictive tool to mimic the thermal control experiment, and the non-thermal effect can thus be quantified by comparing the products yield between illuminating measurement and simulation. In specific cases, the proposed framework offers a solution to quantifying thermal and non-thermal contributions in plasmonic photocatalysis. The lessons learned can then be applied for rational design of photoreactors and catalysts, and for optimization of sunlight-powered chemical processes.

Presenting Author: Sha Li EPFL

Presenting Author Biography: Sha Li obtained her Bachelor degree in Energy and Power Engineering from China University of Petroleum (Beijing) in 2012, and her Master degree in Engineering Thermophysics from Beihang University, China in 2015. She completed her PhD at the Solar Thermal Group from the Australian National University (ANU) in 2020. She was the recipient of the 2020 Graduate Student Award of Solar Energy Division (SED), ASME. She also won the Best Oral Presentation–Third Place in the 2020 ASME Energy Sustainability Conference. Currently, she is a postdoc researcher working with Prof. Sophia Haussener at LRESE from EPFL, Switzerland since April 1, 2021.