Metal-polymer hybrid chemiresistive sensor for low concentration fast hydrogen detection

TL;DR

This paper introduces a novel hybrid Pd-polymer chemiresistive sensor capable of detecting 0.5% hydrogen gas at ambient conditions with high sensitivity, fast response, and cost-effective fabrication, suitable for real-world applications.

Contribution

The study presents a new hybrid Pd-polymer sensor with record sensitivity for low concentration hydrogen detection using a simple, low-cost fabrication method.

Findings

Detects 0.5% hydrogen at ambient conditions

Achieves approximately 30% sensitivity

Exhibits rapid rise time due to surface hydrogen loading

Abstract

Low concentration hydrogen gas detection is of paramount importance both in space applications as well as medical applications. It is also critically important for safe handling of hydrogen below the explosive limit. Here, we report a novel hybrid Pd metal-polymer chemiresistive sensor that can sense 0.5% hydrogen ($H_2$) gas in ambient conditions of temperature and pressure with the highest reported sensitivity($\sim$30%) obtained earlier by a physical deposition technique, making it an extremely good sensor for real life low concentration hydrogen gas detection. The sensor is easy to fabricate and is also extremely cost-effective for commercial applications. The obtained hybrid chemiresistive sensor comprises palladium (Pd) nanocrystals bound by oxygen and nitrogen atoms of a stabilizer Polyvinylepyrollidone (PVP), grown on top of a selfassembled monolayer. The exceptional rise time-constant is proposed to arise from hydrogen loading at the (111) surface of the palladium nanocrystal which is a very fast process and subsequent fast diffusion of the H atoms from the surface into the bulk. An effort to increase the number of available sites by UV-ozone cleaning, resulted in a degradation of the sensing device due to the poisoning of the available sites by oxygen.