Nanostructured Materials Based on Thin Films and Nanoclusters for Hydrogen Gas Sensing

Abstract

In this paper, we present two approaches to synthesize nanostructured metal oxide semiconductors in a form of multi-layer thin films later assembled as a conductometric gas-sensors. The first approach produces a combination of thin solid film of tungsten trioxide (WO3) with nanoclusters of cupric oxide (CuO) prepared by a magnetron-based gas aggregation cluster source (GAS). The second method is a two-step reactive magnetron sputtering forming a nanostructured copper tungstate (CuWO4) on-top of a WO3 film. Both methods lead to synthesis of nanosized hetero-junctions. These greatly improve the sensorial response to hydrogen in comparison with a WO3 thin film alone.

Exploring the Redox Properties of the Low-Miller Index Surfaces of Copper Tungstate (CuWO4): Evaluating the Impact of the Environmental Conditions on the Water Splitting and Carbon Dioxide Reduction Processes

“…The morphologies of the CuWO 4 nanocrystals in different environments, that is, under synthesis conditions, – the conditions for carbon dioxide reduction, ,, and the conditions for water splitting, – were determined based on the surface phase diagrams discussed in the previous sections. The Wulff morphologies were constructed using the atomic configuration with the lowest surface free energy for each surface, using the following relationships σ 1 d 1 = σ 2 d 2 = · · · = σ n d n = c , where σ and d represent the surface free energy and the distance from the center to the surface of the crystal.…”

Impedance Spectroscopy of Hierarchical Porous Nanomaterials Based on por-Si, por-Si Incorporated by Ni and Metal Oxides for Gas Sensors

“…In terms of availability, the most attractive are semiconductor gas sensors. That's why conductometric gas sensors are among the most widely studied and promising devices for detecting gases such as H 2 S [2,3], H 2 [4,5], volatile organic compounds [6][7][8], NO 2 [9,10] etc. Their working principle is based on the measurements of changes in the conductivity of the sensor layer when exposed to the detected gas.…”