Intensive turbulence eddy-induced piezoelectric polarization boosting photocatalytic hydrogen production in ZnO/NF

Fluid eddy-induced piezoelectric effect has been extensively employed to boost photocatalysis. However, the dynamic fluid-induced stress distribution on porous support and the effect of variable surface shear stresses on catalytic activity remain unclear in a rotating fluid-driven piezo-photocatalytic process. Herein, the ZnO-supported porous nickel foam (NF) monolithic catalyst was successfully fabricated, where the interconnected pore network induced intensive turbulence eddies, leading to enhanced light absorption and accelerated mass transport during photocatalysis. Furthermore, the effects of piezoelectric polarization intensity and porosity on hydrogen production via photocatalytic water splitting were systematically investigated. The ZnO/NF particles (porosity: 40 PPI) under flow-field rotation achieved an optimal hydrogen evolution rate of 1.02 mmol·g⁻¹·h⁻¹, representing a 7.3-fold improvement compared to the non-porous conductive glass loaded ZnO (0.14 mmol·g⁻¹·h⁻¹). The computational fluid dynamics (CFD) simulation revealed that the dynamic pressure distribution increased with porosity, whereas the effective light absorption area exhibited an opposite trend, underscoring the role of piezoelectric polarization in enhancing photocatalytic hydrogen production. Additionally, for the scalable production of clean hydrogen, a hydro-cyclonic piezo-photocatalytic reactor for H₂ production was initially designed and assembled under laboratory conditions.