DescriptionThe objective of the research is to develop an innovative approach for a rapid and mass production of macro-3D hierarchical porous hybrids for adsorptive cooling. The most innovative feature of this cooling system is the capability to utilize solar energy or any heat waste as the driving force, which is an energy- favored and environmental-friendly alternative to traditional cooling systems. The macro-3D hierarchical porous hybrids are used as the adsorbent in the cooling system and composed with vertically aligned carbon nanotubes directly grown on highly conductive metal microwires in stainless steel wool. The stainless steel wool has stochastic foam features composed of microwires and pores of wide range of sizes from millimeters down to nanometers. Significantly improved performance for adsorptive cooling by this novel design is expected due to the unique 3D hierarchical porous structures, which not only dramatically increases effective surface area for coolant adsorption and desorption, but also facilitates mass transport of the coolants. Directly growing CNTs on a conductive surface will dramatically improve the contact between the CNTs and the underlying metal substrates, which has been a long-lasting problem and is the key to speed up heat transfer. To reach these goals, several important parameters, such as in-situ catalyst fabrication, growing temperature, flow rates of carbon resourses, reduction and inert carrier gases, were systematically investigated and optimized to grow vertically aligned carbon nanotubes on each metal wire in stainless steel wool. We also have established an adsorptive cooling system to study the cooling cycles using pressure-temperature (P-T) diagram. This system allows us to timely evaluate the refrigeration performance (such as the coefficient of performance, COP) of the fabricated novel 3D hierarchical porous adsorbent. Another part of this thesis is to fabricate urchin-like or flower-like assembled TiO2 nanorods/graphene nanocomposites by a facile hydrothermal treatment using an inorganic titanium source and highly-conductive, low-defective amphiphilic graphene sheets prepared by a microwave-enabled dispersion approach developed by our group. The structures and composition of the flower shaped composite particles and sheets were characterized by scanning electron microscope (SEM), Raman, and ultraviolet visible spectroscopy (UV-Vis), etc. The efficiency enhancement for photocatalytic reduction of CO2 and photocatalytic oxidation of pharmaceutical drug waste in the environment will be examined in future studies.