Graphene Electrode for Studying CO₂ Electroreduction Nanocatalysts under Realistic Conditions in Microcells

Abstract

The ability to resolve the dynamic evolution of electrocatalytically induced processes with electrochemical liquid phase electron microscopy (ec‐LPEM) is limited by the microcell configuration. Herein, we integrate a free‐standing tri‐layer graphene as a membrane and electrode material into the electrochemical chip and evaluate its suitability as a substrate electrode at the high cathodic potentials required for the CO2 electroreduction (CO2ER). The three‐layer stacked graphene was transferred onto an in‐house fabricated single working electrode chip for use with bulk‐like reference and counter electrodes in order to facilitate evaluation of its effectiveness. Electrochemical measurements showed that the graphene working electrode exhibited a wider inert cathodic potential range than the conventional glassy carbon electrode, while achieving good charge transfer properties for nanocatalytic redox reactions. Operando scanning electron microscopy studies clearly demonstrate the improvement in the spatial resolution but reveal a synergistic effect of the electron beam and the applied potential that limits the stability time window of the graphene‐based electrochemical chip. By optimizing the operating conditions, we have achieved the in‐situ monitoring of Cu nanocube degradation at the CO2ER potential of ‐1.1 V versus RHE. Thus, this improved microcell configuration allows for EM observation of catalytic processes at potentials relevant to real systems.This article is protected by copyright. All rights reserved

Advances and Opportunities in Closed Gas-Cell Transmission Electron Microscopy

“…, graphene) is proposed. For liquid-cell TEM applications, common encapsulation materials include silicon nitride (SiN x ), , silicon oxide (SiO x ), graphene, − and TMDCs . These materials exhibit distinct physical and chemical properties, along with variations in processability and scalability.…”