Tailoring Surface-Engineered MXenes for Enhanced Single-Atom Catalysis in Selective Oxygen Reduction

Project description

The electrocatalytic oxygen reduction reaction (ORR) to hydrogen peroxide (H₂O₂) offers a sustainable alternative to the traditional anthraquinone process, which is energy-intensive and environmentally harmful. However, challenges such as poor catalyst selectivity, high overpotentials, and limited stability hinder efficient H₂O₂ production. MXenes, a class of two-dimensional transition metal carbides, nitrides, and carbonitrides, present a promising solution due to their high conductivity, tunable electronic properties, and customizable surface terminations. Their surface chemistry, featuring terminations like -OH and -O groups, modulates oxygen intermediate adsorption and activation, enhancing H₂O₂ selectivity while maintaining stability under various conditions.
The objective of this work is to optimize MXenes for selective H₂O₂ production through tailored surface engineering strategies. The study focuses on synthesizing a family of 3d, 4d, and 5d-based MXenes (Ti₃C₂Tₓ, Mo₂CTₓ, W₂CTₓ) through selective etching of aluminum layers from MAX phases. The MXenes will be further modified through (1) surface functionalization with -OH, -O, and -F groups, (2) heteroatom doping (e.g., N, S, P), and (3) defect engineering to introduce vacancies for enhanced active sites. Additionally, single-atom catalysts (Fe/Co) will be stabilized on MXene surfaces via atomic layer deposition and wet-chemical techniques, ensuring maximum product conversion with 100% selectivity. Electrocatalytic activity studies will be conducted using a three-electrode setup with Ag/AgCl and platinum electrodes. Parameters such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), Tafel plots, electrochemical impedance spectroscopy (EIS), and stability tests (chronoamperometry and chronopotentiometry) will be analyzed to assess the ORR performance and catalyst longevity. By tuning surface properties and optimizing active sites, MXenes can be developed as scalable, cost-effective electrocatalysts for efficient H₂O₂ synthesis, addressing the growing demand for sustainable green oxidants.

Outcomes

The deliverables of this research include the synthesis of different MXenes (Ti₃C₂Tₓ, Mo₂CTₓ, and W₂CTₓ) through selective etching. Surface modifications will be implemented, including different functionalization, heteroatom doping, and defect engineering to enhance electrocatalytic performance. Additionally, Fe/Co single-atom catalysts will be stabilized on the synthesized and modified MXene surfaces to enhance and optimize selectivity for electrocatalytic reactions. The electrochemical activity and performance of the modified MXenes will be thoroughly evaluated, with a focus on their selectivity and efficiency in the oxygen reduction reaction (ORR). Finally, the stability and longevity of the catalysts will be assessed through various electrochemical tests.

Essential capabilities

Understanding of basics of materials chemistry and electrochemistry

Desireable capabilities

Materials characterization and electrocatalysis

Expected qualifications (Course/Degrees etc.)

Masters in Chemistry or MTech in Materials Science and Engineering

Additional information for applicants

note: i-students must have own scholarship to apply (CSIR, UCG-NET, etc)