dissociation and spillover, enabling chemiresistive transduction at room temperature. Finite-element simulations and infrared thermography show that under identical electrical drive, the low-thermal-conductivity glass and double-cavity architecture suppress heat loss and maintain the sensing region ~10 °C higher than planar counterparts. This thermal advantage translates directly into an order-of-magnitude (~10 times) increase in sensitivity at room temperature. By integrating a simplified, bonding-free single glass wafer process with a Pt/NCS-functionalized suspended membrane, this work establishes a scalable, economical, and reliable platform for high-performance, room-temperature hydrogen sensing in microsystem applications.

device delivers 0.016 Wh-more than tenfold higher than previously reported multifunctional systems-demonstrating exceptional scalability. The harvester directly powers a water electrolysis cell, achieving continuous hydrogen evolution without external power. It also exhibits a unique pressure-responsive thermal sensing capability: mechanical loading (10-50 kPa) modulates internal resistance, producing localized Joule heating (50-70 °C) for self-powered thermal actuation. Integrates long-duration hydrovoltaic power, self-powered electrolysis, and pressure-induced thermal sensing in one device. Delivers durable, scalable, multifunctional performance for practical off-grid energy and responsive sensing.