Dr. Guoliang (Greg) Liu, Associate Professor from Department of Chemistry and Department of Chemical Engineering, Materials Science and Engineering, Virginia Tech will give a seminar titled "Design & Engineering of Macromolecules for Energy and Environmental Sciences" to the interested faculty and students at Discovery Park.

Abstracts

I will present two examples of macromolecules for energy and environmental sciences. First, I will describe the synthesis of a new type of porous carbon fibers from block copolymers. Conventional syntheses of porous carbon fibers rely on blending polyacrylonitrile with sacrificial additives, which macrophase-separate and result in poorly controlled pores. Here we use the block copolymer microphase separation to synthesize porous carbon fibers with well-controlled mesopores and micropores. Block copolymers are directly converted to nitrogen and oxygen dual-doped porous carbon fibers. Owing to the optimized bimodal pores and interconnected porous network, the block copolymer-based porous carbon fibers exhibit outstanding ion transport properties and ultrahigh capacitances in supercapacitors. The use of block copolymer precursors revolutionizes the synthesis of carbon fibers. The advanced electrochemical properties signify that porous carbon fibers represent a new platform material for electrochemical catalysis, energy storage and conversion. Second, I will present the upcycling of plastic waste into high-value chemicals. We will discuss a tandem degradation-upcycling strategy to exploit high-value chemicals from PS waste with high selectivity. We first degrade PS to aromatics and then valorize the intermediate to high-value chemicals. Low-cost AlCl3 catalyzes both the reactions of degradation and upcycling at ambient temperatures under atmospheric pressure. The intermediates can advantageously serve as solvents for processing the solid plastic wastes, forming a self-sustainable circuitry. The low-value-input and high-value-output approach is substantially more sustainable and economically viable than conventional thermal processes. The cascade strategy is resilient to impurities from plastic waste streams and is generalizable to other high-value chemicals. The upcycling to diphenylmethane was tested at 1-kg laboratory scale and attested by industrial-scale techno-economic analysis, demonstrating sustainability and economic viability without government subsidies or tax credits.

Biography

Liu earned a bachelor’s degree in chemical engineering from Zhejiang University (China) in 2005. After completing his doctorate in 2011, he conducted postdoctoral research at Northwestern University, where he was named an Outstanding Researcher in the International Institute for Nanotechnology. He joined the Department of Chemistry and affiliated to the Department of Chemical Engineering at Virginia Tech in Fall 2014. Liu holds about two dozen patents. Among them, over ten are licensed or assigned to companies including Intel®, Western Digital®, Ford Motors Company, SABIC, Waves Audio (Israel). Liu has been named an Inventor of the Month at Virginia Tech (2017/07). Liu is a recent recipient of the VT Junior Faculty Award, NSF CAREER award, Air Force Young Investigator Program (YIP) Award, ACS PRF Doctoral New Investigator (DNI) award, ACS PMSE Young Investigator award, and John C. Schug Research Award. He is also named Young Talent or Emerging Investigator of a number of journals including Macromolecular Rapid Communications, Polymer Chemistry, Journal of Materials Chemistry, Molecular Systems Design & Engineering, and ACS Applied Polymer Materials. He chairs the Blackwood Junior Faculty Fellow of the College of Science at Virginia Tech.