New Photocatalytic Materials for Solar Water Splitting and Environmental Remediation
Given that the sun provides the Earth with 120,000 trillion watts (TW) of energy, solar energy conversion represents the most viable means of sustainably producing 13 TW (consistent with global human demand). Photocatalytic water-splitting represents one way of using solar energy to convert a low value substance – water – into a useable fuel – hydrogen – with minimized environmental and political consequences. However, materials must be discovered and developed that efficiently collect solar energy and then use that energy to split water. We are addressing this need with two approaches. One approach aims to enhance the photocatalytic performance of materials by controlling their shape and structure, selectively enhancing features (e.g., specific crystal facets) desirable for photocatalytic performance. Our second approach aims to demonstrate completely new modes of photocatalytic action through the preparation of composite materials (Z-schemes). Composites typically display enhanced electron-hole separations and potentially each composite component can be selectively designed and modified. Advances in photocatalytic materials for solar water splitting can be directly applied to enviornmental remediation projects.
New Directions in Aerosol Chemistry for Materials Synthesis
Aerosol methods are an industrial favorite for the continuous production and processing of compositionally complex inorganic solids; however, developing aerosol routes to architecturally complex particles (e.g., core/shell, porous, or multi-phasic) has only recently been undertaken. Our research aims to achieve this architectural complexity by integrating new chemical methods into ultrasonic spray pyrolysis, an aerosol synthetic technique that uses ultrasound for nebulization. As new particle shapes and architectures are achieved, these results are then correlated with the decomposition behavior of the selected precursors. In turn, a more general platform for precursor selection is being outlined, allowing inorganic solids with previously unachievable compositions and properties to be accessed. Currently, these methods are being applied to the synthesis of catalytic and photocatalytic materials.
Synthesis and Application of Nanoscale Materials
Inorganic crystals with nanoscale dimensions are emerging as important building blocks for multifunctional device fabrication. In recent years, tremendous achievements have been made regarding the preparation of nanomaterials with well-controlled properties. Yet, fundamental questions still remain about their synthesis and many materials (e.g., some precious metals, alloys, and intermetallics) have yet to be synthesized as high-quality samples. Our research aims to understand and control the nucleation and growth processes of metals to predictably prepare new nanomaterials for use in catalytic applications. Current emphasis is on the synthesis of noble metal alloyed particles with tunable compositions and controlled shapes as well as understanding the underlying chemistry of nanosyntheses and how it directs nanoparticle nucleation and growth.
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