3-D Nanowire Heterostructures from Earth Abundant Materials by Low-cost Fabrication Process for High-efficiency Photoelectrochemical Hydrogen Generation

University Of California-San Diego, La Jolla CA

Investigators

Abstract

PI: Wang, Deli Proposal Number: 1236155 Institution: University of California-San Diego Title: D Nanowire Heterostructures from Earth Abundant Materials by Low-cost Fabrication Process for High-efficiency Photoelectrochemical Hydrogen Generation Sunlight and seawater are the ultimate sustainable energy sources on earth. Together they constitute a potential solution to the global energy crisis and at the same time can reduce carbon emission due to the use of fossil fuels. A photoelectrochemical (PEC) cell utilizes solar energy to directly split water and generate hydrogen, which is clean and free of carbon emission. However, it is broadly recognized by the PEC community that there is no single material that can be the perfect photoelectrode candidate for solar water splitting with respect to light absorption, water reduction, chemical stability, etc. This project will investigate the use of three-dimensional (3-D) tree-like branched nanowire heterostructures from earth abundant materials by low-cost fabrication process as photoelectrodes for high efficiency and potentially, a practical and sustainable clean hydrogen generation. The array of the tree-like 3-D branched nanowires offers a unique combination of desired properties that are critical to high efficiency PEC hydrogen generation, including enhanced light absorption, improved charge separation/collection, enlarged surface area, and better electrochemical reaction dynamics. Specifically, the proposed research focus will be on (i) design and fabrication of the 3-D nanostructured photoelectrodes using earth abundant materials (Si, Cu2O, Fe2O3, etc.) by low-cost solution processes, (ii) understanding of the interface between the nanowire core and branches and their effect on separation and transport of the photogenerated charge carriers, and (iii) understanding of the electrolyte/nanowire interface, in particular the surface electrochemical reaction/corrosion of semiconductor electrodes at high local acidic/basic conditions. Chemically robust materials such as TiO2 and WO3 will also be studied. The research will develop an understanding of the fundamental materials science and chemistry questions regarding heterojunctions formation in nanomaterials and interfaces, as well as create a new paradigm of heterogeneous functional integration at nanoscale. Specifically with regard to renewable energy research, this work will also shine a light on design and fabrication/manufacturing of high-efficiency photovoltaic devices and H2 generation. In addition, the project will provide opportunity to the undergraduate and graduate students to obtain training in the interdisciplinary areas related to this project.