Fabrication of in-situ grown and Pt-decorated ZnO nanoclusters on new-type FTO electrode for room-temperature detection of low-concentration H2S

Abstract In this work, an in-situ grown and Pt-decorated ZnO nanoclusters (NCs) gas sensor was fabricated by employing etched FTO glass as the growth substrate and gas-sensing electrode via facile dip-coating assisted hydrothermal route and physical mixing method, which exhibited superior gas-sensing performance for low-concentration H2S at room temperature. Benefiting by the in-situ growth, good ohmic contacts between ZnO NCs and FTO electrode are formed, which maximize the gas-sensing performance and enhancing the stability of the sensor. On this basis, ZnO NCs with top cross-linked structure can provide adequate grain-boundary potential barriers and self-assembled electron pathways, as well as larger effective surface area and gas diffusion space. What's more, Pt nanoparticles (NPs) decoration on the surface of ZnO NCs can introduce more catalytic sites and proper Schottky barriers for gas-sensing tests. Due to their synergistic effects, the in-situ grown and Pt-decorated ZnO NCs sensor exhibit excellent room-temperature gas-sensing behaviors for H2S. Among samples, 1.5 at% Pt-decorated ZnO NCs sensor possesses the highest response value, excellent selectivity, repeatability and stability, which achieves the room-temperature detection of H2S at ppb level. In addition, the effect of Pt decoration on the gas-sensing behaviors under high temperature condition and the mechanism of enhancing gas-sensing performance were also systematically investigated.