Unfolding the hydrogen gas sensing mechanism across 2D Pnictogen/Graphene heterostructure sensors

Abstract

Hydrogen as a source of clean and future alternative to fossil fuels demands a class of powerful gas sensor technologies. To this end, we have developed unique bi-stacked heterogeneous layers based on 2D Pnictogens and graphene sheets via photolithography and pattern transfer methods. The nanoengineered heterostructure morphology consists of truncated/hexagonal antimonene flakes dispersed on graphene sheets. Amongst the Pnictogen class, the hybrid antimonene-graphenes (Sb/G) demonstrated excellent sensing behavior characterized by a large gas response to H2 (~4-fold improvement), high selectivity, fast response/recovery times (>3 fold reduction), and ultra-low limit of detection (LOD: 0.05 ppm) in comparison to pristine sensors. The microstructural and density functional theory (DFT) calculations demonstrated a Bader charge transfer mechanism from Sb/G heterojunction to the H2 gas, which modulated the Schottky barrier and improved gas response. The outstanding performance of the Sb/G sensor places it amongst the highly selective and fast hydrogen sensors based on the Pnictogen-graphene family.

Enhancement of H2 Gas Sensing Using Pd Decoration on ZnO Nanoparticles

“…Since, in this layer, the concentration of electrons is lower relative to the core parts of the ZnO NPs, the formation of an EDL causes an overall increase in the sensor resistance relative to vacuum conditions [37]. Upon exposure to H2 gas, the following reaction between H2 and the adsorbed oxygen is likely [38]:…”