Effect of Nanoparticles on Contact Electrification during Water Intrusion–Extrusion into/from Hydrophobic Nanopores

Abstract

Solid–liquid triboelectric generation is a widespread phenomenon relevant for many natural and technological processes. In particular, solid–liquid triboelectric nanogenerators (TENGs) are an emerging approach for sensing and harvesting dispersed mechanical energy and converting it into electrical power. Triboelectric energy generation relies on charge transfer during contact and separation of different materials, combined with electrostatic induction. Compared with conventional sliding, immersion, or pressing modes, the intrusion–extrusion of liquids into and out of hydrophobic nanopores offers promising advantages, including an enlarged effective contact area and the potential for device miniaturization. However, when water is used as the working liquid, limited charge mobility and weak polarization result in low electrical output. To address these limitations, nanofluids represent a promising alternative. In this work, we investigate how minor concentrations of gold nanoparticles affect triboelectrification during water intrusion–extrusion into-from hydrophobic nanoporous silica. The introduction of gold nanoparticles leads to enhanced triboelectrification and an unexpected reversal of the triboelectric peak polarity. The experimental results indicate that nanoparticle size plays a significant role in determining the electrical response. This approach highlights new opportunities for tuning intrusion–extrusion TENG (IE-TENG) performance and may contribute to the development of advanced sensing and energy-harvesting devices.