Mesoporous nano-crystalline titania structures for hydrogen sensing

Abstract

A structure includes a substantially non-conductive frame having an exterior surface. The structure defines a plurality of passages that open to the exterior surface. Mesoporous material is disposed in the plurality of passages and is supported therein by the frame. In a method for making a mesoporous nanocrystalline titania hybrid material, a templating agent, an acid, and a titania precursor is mixed into a template liquid. A frame that defines a plurality of passages is placed into the template liquid. A solvent is evaporated from the template liquid, thereby forming a titania gel encapsulating the templating agent. The gel is heated to remove substantially the templating agent from the non-conductive frame and the titania, thereby leaving a mesoporous titania material.

Description

BACKGROUND [0001] 1. Field of the Invention [0002] The invention relates to nanoscale structures and, more specifically, to a nano-crystalline titania structure that may be used in sensor applications. [0003] 2. Description of the Prior Art [0004] Presently, hydrogen sensors employ electrochemical, optical or thermal detection methods. One system employs titania nanotubes arranged in an array. Such systems generally have pore sizes of greater than about 20 nm. Thus, the surface area of the sensing element is limited, thereby limiting performance indicia such as response and sensitivity. Recently, there has been renewed interest in metal oxide semiconductor-based devices. In titania, for example, the presence of hydrogen can dramatically change the resistivity of the material through a variety of physical mechanisms. The most common sensors depend on Schottky barrier modulation in structures with Pd or Pt electrodes. Present systems that utilize titania suffer from poor selectivity a...

AI Technical Summary

Problems solved by technology

Thus, the surface area of the sensing element is limited, thereby limiting performance indicia such as response and sensitivity.

Present systems that utilize titania suffer from poor selectivity and slow response times.

The conventional porous materials with regular pore sizes, such as zeolites, have limitations in pore diameter size, while those with large pores have widely varying pore sizes.

Existing methods are limited by a combination of high cost, limited sensitivity, poor selectivity and slow response times. Contamination of the sample and subsequent performance degradation also limit existing systems use.

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