Functional materials for photovoltaics and hydrogen energy

Functional Materials for Hydrogen Energy
Hydrogen energy systems' functional materials, like catalysts, storage materials, and fuel cell conductive materials, greatly influence operational efficiency. Traditionally used catalysts such as platinum and iridium are excellent in promoting water splitting for hydrogen production. However, due to resource shortage and cost issues, alternatives like nickel, iron, and cobalt-based catalysts are being explored. Complex metal hydrides, especially those formed from light elements like lithium, boron, and aluminum, are promising for hydrogen storage due to their high capacities and enhanced kinetics via nanostructuring. In the quest for more efficient fuel cell materials, potential contenders like palladium, gold, and carbon-based materials like graphene and carbon nanotubes, along with platinum-based catalysts, are under consideration. Functional materials for hydrogen energy are witnessing remarkable innovation. One notable development is the atomically dispersed iron-nitrogen-carbon catalysts (Fe-N-C) for proton-exchange membrane fuel cells (PEMFCs), offering performance competitive to traditional platinum-based catalysts. Moreover, artificial intelligence (AI) and machine learning (ML) integration in material science accelerates the discovery and design of new materials, predicting their properties and speeding up candidate selection. Hydrogen storage advancements, particularly the development of metal-organic frameworks (MOFs) for solid-state storage, are remarkable, offering high surface areas for efficient hydrogen physisorption. Case studies reveal significant progress in this field. A synthesized Fe-N-C catalyst showed superb oxygen reduction reaction (ORR) activity and stability, reducing the need for platinum in PEMFCs. An AI-discovered new class of nitrogen-doped carbon nanotubes emerged as an efficient ORR catalyst, outperforming many non-precious metal catalysts in a PEMFC environment. Finally, a unique MOF for hydrogen storage with high storage capacity was developed, surpassing U.S. Department of Energy targets. These developments indicate important strides towards fully leveraging hydrogen's potential as a sustainable energy source.