Electrochemical stability of Au-TEM grid with carbon supporting film in acid and alkaline electrolytes for identical-location TEM study

Abstract

Identical-location transmission electron microscopy (ILTEM), which utilizes a labeled TEM grid for both electrochemical measurement and TEM characterization of the same location, plays an indispensable role in ex-situ study of structural evolutions of nanoscale electrocatalysts. The stability of the Au TEM grid particularly the coated carbon supporting film is a critical issue for the implementation of ILTEM techniques of electrocatalysts working at highly oxidative potentials such as oxygen evolution reaction (OER). Here, we report the electrochemical stability of Au TEM grid coated with carbon supporting film at potentials up to 1.8 V/RHE in both acid and alkaline electrolytes. While showing a higher extent of corrosion in alkaline electrolyte, the carbon supporting film coated on the Au grid generally exhibited a good stability (<10% damage ratio) when holding at constant potentials up to 1.6 V/RHE in both acid and alkaline electrolytes. The likely Au dissolution and re-deposition at the OER potentials up to 1.8 V was also studied. Our results not only support the feasibility but also provide a guidance for ILTEM studies of oxygen evolution electrocatalysts or other electrocatalysts working at oxidative potentials.