3D MAX & 2D MAXene nanomaterials and Egypt Pyramids
A Possible Partial Solution to the Mystery of the Great Pyramids of Egypt
Professor Michel W. Barsoum
Department of Materials Science and Engineering,
Drexel University, Philadelphia, PA 19104
Dr. Michel Barsoum is Distinguished Professor in the Department of Materials Science and Engineering at Drexel University. He is an internationally recognized leader in the area of MAX phases with over 250 papers on the these phases alone including ones in top-tier journals such as Nature and Science. With a h index of 50, his work has been highly and widely cited. He is on ISI’s most highly cited authors list. He is the author of two entries on the MAX phases in the Encyclopedia of Materials Science, and a book, MAX Phases: Properties of Machinable Carbides and Nitrides published in 2013. He is also the author of Fundamentals of Ceramics, a leading textbook in his field. In 2000 he was awarded a Humboldt-Max Planck Research Award for Senior US Research Scientists and spent his sabbatical year at the Max Planck Institute in Stuttgart, Germany. He is a fellow of the American Ceramic Society and the World Academy of Ceramics. In 2008 he spent his last sabbatical at Los Alamos National Laboratory as the prestigious Wheatly Scholar. Since 2008 he has also been a visiting professor at Linkoping University in Sweden.
For about 4500 years, the mystery of how the Great Pyramids of Giza were built has endured. How did the Ancient Egyptians pull 70 ton granite slabs up an earthen ramp —without the benefit of wheels— 2/3 up the Great Pyramid? How did they carve granite, with pure copper? In some cases, adjacent blocks fit so well together that, even today, a human hair card cannot be inserted between them. Most important of all, to this day, Egyptologists have yet to explain how the tops of the pyramids were built. In this talk, I will present compelling scientific evidence – including C-dating results - that some of the pyramid blocks were cast using a combination of weathered limestone, diatomaceous earth and lime. Additionally I will also review the work of a Norwegian architect, O. Bryn who has essentially figured out how the pyramids were built. The historical, archeological, and technological implications of our conclusions to today’s world are profound and will be touched upon.
From MAX to MXene - From 3D to 2D Nanomaterials
By now it is well-established that the layered, hexagonal carbides and nitrides with the general formula, Mn+1AXn, (MAX) where n = 1 to 3, M is an early transition metal, A is an A-group (mostly IIIA and IVA) element and X is either C and/or N – sometimes referred to as polycrystalline nanolaminates because every basal plane is a potential deformation or delamination plane - combine some of the best attributes of metals and ceramics. More recently we have shown that by simply placing MAX phase powders at room temperature in HF, the A-layers are selectively etched to produce 2D materials that we labeled MXenes to emphasize the loss of the A-group element and their similarities to graphene. Unlike hydrophobic graphene, MXenes are hydrophilic that behave as “conductive clays”, a hitherto unknown combination. MXenes such as Ti2C, V2C, Nb2C and Ti3C2 can be used as electrode materials in lithium-ion batteries (LIBs) and supercapacitors (SC’s) with performances that are quite impressive. In all cases, when used as anodes in LIB, MXenes showed an excellent capability to handle high cycling rates. Flexible additives-free electrodes of delaminated Ti3C2 showed reversible capacities of > 400 mAhg-1 at 1 C and 110 mAhg-1 at 36 C, the latter for > 700 cycles. SC's with volumetric capacities of > 300 F/cm3 were also demonstrated. More recently volumetric capacitances of > 900 F/cm3 were obtained. The potential of using MXenes in energy storage and other applications will be highlighted.