Considerable attention has been drawn towards understanding the unique properties of carbon nanomaterials and exploring their potential applications in electrochemical energy conversion and storage. The electrochemical characteristics of nanostructured carbon materials can be significantly altered by the presence of defects, dopants, adsorbates, interfaces, and stresses. In addition, the solvent and applied bias may have substantial influence on electrochemical processes at the electrode/electrolyte interface. However, there is a fundamental lack of understanding as to the nature and role of the chemical and structural modifications and the solvent and bias effects, let alone the synergistic interplay between them in determining the performance of carbon-based electrochemical devices. Unlike the case of conventional metal electrodes, the potential drop across the electrical double layer at the electrode-electrolyte interface can deviate substantially from the applied voltage (øapp) due to a shift of the Dirac point with charging. This may in turn significantly alter the interfacial capacitance and the relationship between øapp and free-energy change (ΔF). Hence, accurate evaluation of the electrode contribution is necessary to better understand and optimize the electrochemical properties of carbon nanomaterials. In this talk, based on systematic first-principles evaluation of the øapp-ΔF relation, we present the electronic, geometric and catalytic natures of active sites for important electrochemical reactions including oxygen reduction reaction. We will also touch briefly on charge storage mechanism in nanoporous carbons for supercapacitors and possible occurrence of faradaic reactions which may cause self-discharge.

Understanding and design of carbon nanomaterials for electrocatalysis from first principles

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.