题  目：A Synchrotron Analysis of High Current Density CO₂ Electrolysis Devices

报告人：Brian Seger教授 

单  位：丹麦技术大学

时  间：2024/11/16  10:30

地  点：海西院235报告厅

－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－

报告简介：This talk will analyze CO₂ electrolysis from a device perspective to provide insight into what are the bottlenecks in the field and how to resolve them.  We will focus on our synchrotron based results using small angle and wide angle x-ray scattering as well as x-ray fluorescence to observe CO₂ electrolysis devices in real time while concomitantly measuring anode and cathode product distributions.  During higher current density (>100 mA/cm²) CO₂ electrolysis devices are prone to cathodic ‘flooding’ leading to greatly enhanced hydrogen production, which can occur via a chaotic oscillatory nature.  Via our various in-situ analysis tools, we can explain the basis for this flooding, which is primarily due to salt deposition.¹ By analyzing various salts (Li⁺, Na⁺, K⁺, Cs⁺) of differing solubility we show this trend more clearly.² As Cs cations fluoresce,³ this allows us to show how an applied potential drags these cation salts through an anion exchange membrane, leading to the salt build-up and concomitant deposition in these electrolyzers.    

As CO electrolysis allows us to switch to more soluble hydroxide salts,we show this is a major key to ensuring long-term stability (>100 hours).⁴  However practical issues such as anodic dissolution of IrO₂ can redeposit on the cathode producing hydrogen as shown by our synchrotron results. Switching to a nickel anode resolve this,however we show that the anodic pH must be controlled to prevent acetate/acetic acid from driving the pH down,and thus corroding the device.

References:

1 Moss,AB,Garg,S,et al. Joule 2023,7,2,350-365

2 Garg,S. Xu,Q,et al. Energy & Environmental Science,2023 16,1631-1643

3 Xu,Q,Garg,S,et al. Nat. Cat. 2023,11,1042-1051

4 Joensen,B,Xu,Q. et al. Joule 2024,8,6,1754-177

个人简介：BrianSegerreceived his B.Sc inChemical Engineering from the University of Toledo in 2003, and worked with Prashant Kamat at the University of Notre Dame where he received his PhD in 2009.  After a year post-doc with Lian Zhou Wang in the University of Queensland, he started at DTU Physics as a postdoc and is now a full professor in Physics.  His earlier work focused on fuel cells and photoelectrochemistry, with more recent work focusing on electrosynthesis studies particularly related to CO₂ and CO electrolysis.