Overview: 1D nanomaterials, nanotubes and nanowires, offer exciting properties resulting from radial quantum confinement. The microscopic scale along the axis provides an intrinsic path to "communicate/manifest" these properties. Despite rapid progress, there is a considerable gap between sought-after applications and synthesis. To address this long-standing roadblock in the course of bringing nanotechnology to fruition, we are proposing a research project of using bimetallic nanocatalysts to achieve controllable synthesis. Nanocatalyst properties can be tuned rationally and continuously by stematically adjusting the ratio and chemical composition to probe the interaction between nanocatalysts and vapor precursors. A catalyst design guideline to enhance selective growth by synchronizing material incorporation with diffusion and precipitation will be set forth. A rigorous investigation of 1D nanomaterial growth will be conducted to test our central hypothesis - synergetic interaction between nanocatalysts and vapor precursors can be achieved by tailoring solubility and compound formation tendency using bimetallic catalyst systems with two distinct catalyst species. Bimetallic nanocatalysts with continuously varied properties will be synthesized by adjusting the molar ratio of catalyst and cocatalyst species, allowing a systematic study of nanocatalysts in 1D nanomaterial growth for the first time. New types of high-contrast diblock copolymers will be used to synthesize bimetallic nanocatalysts. These block copolymers will selfassemble in solution to form micelles with the block composing the core, capable of sequestering a wide range of metal species. Controlled self-assembly and metal sequestration processing will be established to yield uniform bimetallic nanocatalysts with tunable chemical composition. Empowered by these highly engineered nanocatalyst systems, a systematic investigation of the role of nanocatalysts in growth will be undertaken for unveiling the growth mystery. To harness controllable synthesis soon-to-be acquired a novel three-dimensional architecture will be directly fabricated. The scientific and technological significance of this new and unique platform will be explored.
Technical Merits: A general synthetic strategy for creating nanocatalysts of any type with controlled size and composition paves a path for understanding the growth mechanisms using the catalytic vapor deposition techniques. The greatly advanced knowledge of catalyst functions in growth will culminate in a new catalyst design paradigm for significantly enhancing 1D nanomaterial synthesis controllability. The proposed block copolymer approach is fully compatible with IC fabrication, nanocatalyst arrays can be readily created on substrates. The ability to generate small and highly active nanocatalysts, extremely small 1D nanomaterials can be directly synthesized on device substrates for enabling revolutionary devices, such as nanowires with extremely high ZT for energy harvesting and ultrahigh sensitivity nanowires as bioactuators. The proposed novel 3D building block which contains undisturbed 1D nanomaterials arranged in parallel in a 3D configuration will inspire new device concepts. The successful outcome of the proposed work will greatly contribute to the advancement of 1D nanoscience and nanotechnology. Our expertise in nanocatalyst and 1D nanomaterial synthesis and free access to state-of-the-art equipment, provide a solid scientific foundation and necessary infrastructure for the proposed project. The PI's project management skills accrued over 10 years working in two leading industrial research Labs(IBM and Agilent) offer the necessary ingredients to conduct this interdisciplinary research.
Broader Impact: The impact of creating a simple but powerful strategy to create nanocatalysts will contribute to the broader field of catalysis, e.g. biomass conversion, greenhouse gas decomposition and oxygen reduction in fuel cells. Greatly advanced knowledge in 1D nanomaterial growth will not only guide the controllable synthesis of a broad range of existing 1D nanomaterials but also will facilitate the creation of new material systems and the discovery of new properties as a consequence. Following the funding of the proposal, the PI will create a brand new research area in nanocatalysis at the newly commenced UC campus in Merced. A lab module will be set up and incorporated into "MSE 126 Nanofabrication". Through an experiential process with nanocatalyst synthesis and 1D nanomaterial growth and characterization, students' interest in nanoscience and nanotechnology will be stimulated. The PI will make an explicit and concerted effort to close the education gap by actively recruiting minority students to work in her lab for their senior capstone projects. This highly interdisciplinary research program will offer both undergraduate and graduate students training that cuts across fields and prepares them to be at the scientific and technological forefront and will inspire others to follow.
