Polydopamine-Modified BaTiO ₃ Nanocubes for Piezocatalytic Water Splitting via Interfacial Electron Modulation

Utilization of low-power vibrational energy for hydrogen (H2) production via piezocatalysis has attracted increasing attention. However, the relatively low efficiency of barium titanate (BaTiO3, BT)-based piezocatalysts for water splitting remains a critical challenge. This study presents a nanoscale surface-engineering strategy to enhance piezocatalytic water splitting by constructing a well-defined core–shell architecture using BT nanocubes and a polydopamine (PDA) shell. In this strategy, BT nanocubes with an intrinsic piezoelectric response are synthesized via a one-step solvothermal method, and subsequently their surfaces are modified with a polydopamine (PDA) surface layer. The optimized PDA-modified BT exhibits an H2 production rate of 1125 μmol·g–1·h–1 during water splitting under ultrasonic vibration, representing a 3.3 times higher rate than pristine BT. Raman spectroscopy and piezoresponse force microscopy confirm the existence of a local noncentrosymmetric structure and intrinsic piezoelectric response in the nanosized BT nanocubes. The reduced electrical impedance further demonstrates that PDA modification significantly improves the efficiency of the piezo-induced carrier separation and migration. This work highlights nanoscale interfacial engineering of conductive polymer shells as an effective strategy for designing advanced piezocatalytic nanomaterials for sustainable energy applications.