Evènement
PhD Defense Ruchao Gao
ISM - Groupe Nanosystèmes Analytiques (NsysA)
Thursday, 4th December 2025 at 2pm
Amphi 3, ENSMAC
Title : Synthesis of advanced functional materials via bipolar electrochemistry for catalytic applications
Abstract:
Bipolar electrochemistry enables wireless asymmetric modification of both conducting and semiconducting objects, thereby allowing the fabrication of Janus particles. When an object is placed in an electric field generated by two driving electrodes, a potential difference is established at its two ends. Redox reactions will be triggered simultaneously at opposite ends once the potential difference is sufficiently high. By adjusting the direction and intensity of the electric field, this modification can be precisely controlled.
The aim of this thesis is to synthesize advanced functional materials using bipolar electrochemistry and exploring their catalytic applications. First, graphene monolayers were introduced as a model 2D material to investigate the feasibility of bipolar electrodeposition. Metals, metal coordination compounds, and polymers can be deposited at desired positions of a graphene monolayer, resulting in multifunctional hybrid objects with self-propulsion and chemiluminescence properties. The modified graphene monolayer can also be used to fabricate enzymatic swimmers with controlled dynamic behavior by applying an external magnetic field. Furthermore, by coupling bipolar electrochemiluminescence with a magnetic field, a graphene-based 2D rotor is designed in order to combine bipolar electrochemistry with rotational dynamics. Then, the scope of bipolar electrochemistry was also extended to MXene microsheets to evaluate the applicability of this approach to other 2D materials.
In the last part of this thesis, light-assisted bipolar electrochemistry was introduced for the modification of semiconducting materials. This synergy of light and electric field enables selective modification of one side of semiconductor particles. By adjusting the electric field intensity and the duration of application, the size of the deposited area could be precisely tuned. Finally, the site-selective modified semiconductor particles show enhanced photocatalytic performance for environmental remediation.
Jury:
M. GIRAULT Hubert, Professeur, Ecole polytechnique fédérale de Lausanne, Suisse, Rapporteur
M. ETIENNE Mathieu, Directeur de Recherche, CNRS Nancy, France, Rapporteur
M. MANO Nicolas, Directeur de Recherche, CNRS Bordeaux, France, Examinateur
M. ZIGAH Dodzi, Professeur, Université de Poitiers, France, Examinateur
Mme. ZHANG Lin, Professeur, Henan University, China, Co-directrice de thèse
M. KUHN Alexander, Professeur, Bordeaux INP, France, Directeur de thèse