Building HKUST-1 metal organic frameworks on a board of Cu tubular micromotors with adaptive propulsive capabilities

Abstract

Herein we present one step simplified synthesis of tubular Cu micromotors based on Hong Kong University of Science and Technology (HKUST-1) metal organic frameworks (MOFs). Tubular Cu/Pt, Cu/Ni and Cu/Ni/Pt micromotors prepared via template electrodeposition are smartly used as nucleation spots for the synthesis of HKUST-1 MOFs by incubating with the specific ligand, benzene-1,3,5-tricarboxylic acid, without any harsh conditions. The inner engines impart the micromotors with adaptive propulsion mechanisms for future applications: magnetic, catalytic, and hybrid magnetic and catalytic modes, reaching speeds of up to 275 μm s⁻¹. Furthermore, stability studies reveal a delayed degradation of the HKUST-1 MOFs in the micromotors as compared with the free MOFs. The synthesis rationale and delayed stability of the HKUST-1 MOFs in water has been exploited for compound encapsulation and controlled release, as illustrated using fluorescein as the model molecule. This approach has unlocked a new range of possibilities for future applications, offering a promising platform for the development of functional micromotors with improved capabilities.