The energy shortage and environment pollution are two serious issues worldwide for human beings, which call for ever-increasing demand towards renewable energy production, efficient energy utilization and environmental protection. Efficient enabling and utilization of various functional devices represent an essential solution to pursue the environment and energy sustainability. Nanotechnology is emerging as an effective approach to improve the efficiency of functional devices for a variety of applications such as light harvesting, energy storage, gas sensing and emission control. Scalable integration of functional nanostructural entities such as nanoparticles, nanowires, nanosheets into applicable three-dimensional (3-D) platform holds the keys of industrial-relevant manufacture of these functional devices. Among all the integration approaches, the wet-chemical based integration is one of the top options due to its advantages in low-cost, flexibility in substrate geometry and composition, ease of operation, and high repeatability. The wet-chemical based processes usually require continuous heating to initiate the chemical reactions, which is regularly achieved by conventional resistive heating.However, such conventional heating method is plaqued by a poor heating efficiency. Moreover, the conventional heating is not suitable for those substrates with three-dimensional (3D) or complex geometry since it hardly provides sufficient heat transfer and mass transport within substrates, leading to poor uniformity of nanostructure deposition and low production rate. Thus, there is urgent demand to develop high-efficiency wet-chemical based integration strategy for nanostructured functional devices. In this project, we propose to develop a novel microwave-irradiation-intensified hydrothermal manufacturing process for scalable manufacture of nanostructured monolithic devices. A wide array of metal oxide nanostructured coatings will be in situ grown on various 3D substrates such as ceramic honeycombs. To improve the growth efficiency, production rate, and distribution uniformity of various nanostructures, microwave irradiation will be introduced to substitute conventional heating sources such as oven and water bath. Mechanical agitation will be used to induce continuous mass transport in substrates. The microwave-induced enhancement on growth efficiency will be investigated with respect to the resulting chemical and physical characteristics of prepared nanostructured devices. The synthesis and processing protocols will be optimized by studying a variety of parameters including microwave power output, pulse frequency and solution flow dynamics. Finally, the production rate of proposed integration strategy will be compared with the typical batch process being used in current industrial manufacturing of nanostructured devices. As a proof of concept, a couple of scale-up monolithic devices will be fabricated and validated as field-relevant catalytic reactors emission control and other environmental remediation.
