MXene-based 2D heterostructures for high-efficiency oxygen evolution reaction: A first-principles study

Title : MXene-based 2D heterostructures for high-efficiency oxygen evolution reaction: A first-principles study

Abstract:

MXenes, generally expressed as Mn+1XnTx (where (M) is an early transition metal, (X) is carbon and/or nitrogen, and (Tx) represents surface terminations such as O, OH, or F), exhibit tunable electronic structures and rich surface chemistry that make them highly promising for photocatalysis. Achieving high photocatalytic efficiency, however, requires designing heterostructures that promote spatial separation of photogenerated electrons and holes across different layers to suppress recombination and improve reaction activity. Despite this potential, constructing MXene-based type-II heterostructures remains challenging, as only specific material combinations can provide the suitable band alignment needed for efficient charge separation. In this work, a first-principles investigation was carried out to develop several MXene-based heterostructures by integrating MXenes with Blue Phosphorene (blueP) and transition-metal dichalcogenides (TMDCs). Phonon dispersion, elastic constants, and molecular dynamics simulations confirmed the mechanical and dynamical stability of all proposed systems. Their suitability for photocatalytic application was systematically evaluated based on electronic band gaps (>1.2 eV), band alignment determined using empirical model DFT method, optical absorption characteristics, and the Gibbs free energy of reaction intermediates. Among the investigated vdW heterostructures, the MXene/TMDC system exhibited exceptional activity toward the oxygen evolution reaction (OER), achieving a remarkably low theoretical overpotential of 0.17 eV. For the MXene/blueP system, biaxial strain engineering effectively improved the catalytic performance by lowering reaction energy barriers, resulting in an OER overpotential of 0.37 eV compared to the unstrained case. This study highlights MXene-based vdW heterostructures as promising photocatalysts for the OER and demonstrates that interface design and strain engineering are effective strategies for advancing next-generation photocatalytic energy conversion technologies.

Keywords: First principle calculation, MXene/BlueP heterostructure, External tuning parameter, Photocatalysis, HER,-OER, Gibbs free energy

Biography:

Sarga P. K. is a Ph.D. scholar in the Department of Physics at BITS Pilani, K.K. Birla Goa Campus, working under the supervision of Dr. Swastibrata Bhattacharyya. Her research focuses on first-principles calculations using density functional theory (DFT), with an emphasis on 2D materials, MXene-based heterostructures, and their applications in photocatalysis and energy storage. She has conducted extensive studies on the electronic, interfacial, and catalytic properties of 2D heterostructures, exploring tuning strategies such as strain engineering and external fields to optimize material performance. She currently has four publications in peer-reviewed journals.