2D Hybrid Superlattice-Based On-Chip Electrocatalytic Microdevice for <i>in Situ</i> Revealing Enhanced Catalytic Activity

Abstract

A molecule-confined two-dimensional (2D) hybrid superlattice is emerging for uncovering the chemical properties as well as distinctive physical phenomenon arising from the interface electronic states. An efficient and convenient synthetic method represents an important precondition to implementing the superlattice in terminal applications and functional devices. Herein, we develop an approach of spontaneous molecular intercalation to obtain a TaS₂-N₂H₄ hybrid superlattice through simple solution immersion processing at room temperature. A cross-sectional high-angle annular dark field image verifies that the N₂H₄ molecules intercalate into the TaS₂ lattice, and the interlayer spacing expands approximately 1.5 times. Combining electrical transport testing and theoretical calculations, electron transfer from N₂H₄ to the S-Ta-S lattice induces enhanced superconductivity and the suppression of the order of charge density waves. Moreover, electrical and Kelvin probe force microscope measurements reveal that intercalary N₂H₄ molecules ensure that the superlattice has higher conductivity and a lower surface work function at room temperature. A 2D hybrid superlattice-based on-chip electrocatalytic microdevice was fabricated through <i>in situ</i> molecular intercalation to directly evaluate the catalytic performance. Benefiting from electronic state regulation, the hybrid superlattice is more active. The presented intercalation method would aid in exploring efficient catalysts and discovering fundamental 2D physics.