Microwave shock-driven thermal engineering of unconventional cubic 2D LaMnO3 for efficient oxygen evolution

Abstract

The phase engineering of two-dimensional (2D) perovskite oxides offers a powerful strategy for enhancing the oxygen evolution reaction (OER), but synthesizing unconventional phases while maintaining their delicate 2D morphology poses significant challenges. Among these, the cubic phase of LaMnO₃ holds great promise due to its superior electronic and structural properties, yet its formation is hindered by high thermodynamic barriers. Herein, we present a microwave shock-driven synthesis approach that overcomes these limitations, enabling the rapid fabrication of cubic-phase LaMnO₃ nanosheets with a preserved porous 2D architecture. This method leverages ultrafast thermal gradients to induce phase transitions, bypassing the high-energy constraints of conventional synthesis routes. The cubic LaMnO₃ catalyst exhibits outstanding OER activity, achieving a low overpotential of 290 mV at 10 mA cm⁻² and a Tafel slope of 66.21 mV dec⁻¹ in 1.0 M KOH. Density functional theory (DFT) calculations reveal that cubic symmetry optimizes Mn 3d and O 2p orbital hybridization, enhancing charge transfer and oxygen intermediate activation. This study demonstrates the potential of microwave shock-driven phase engineering as a robust platform for designing high-performance 2D electrocatalysts, offering new insights into advanced catalyst development.