Browsing by Author "Advincula, Paul A."

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    High-surface-area corundum nanoparticles by resistive hotspot-induced phase transformation
    (Springer Nature, 2022) Deng, Bing; Advincula, Paul A.; Luong, Duy Xuan; Zhou, Jingan; Zhang, Boyu; Wang, Zhe; McHugh, Emily A.; Chen, Jinhang; Carter, Robert A.; Kittrell, Carter; Lou, Jun; Zhao, Yuji; Yakobson, Boris I.; Zhao, Yufeng; Tour, James M.; Smalley-Curl Institute; NanoCarbon Center; Welch Institute for Advanced Materials
    High-surface-area α-Al2O3 nanoparticles are used in high-strength ceramics and stable catalyst supports. The production of α-Al2O3 by phase transformation from γ-Al2O3 is hampered by a high activation energy barrier, which usually requires extended high-temperature annealing (~1500 K, > 10 h) and suffers from aggregation. Here, we report the synthesis of dehydrated α-Al2O3 nanoparticles (phase purity ~100%, particle size ~23 nm, surface area ~65 m2 g−1) by a pulsed direct current Joule heating of γ-Al2O3. The phase transformation is completed at a reduced bulk temperature and duration (~573 K, < 1 s) via an intermediate δʹ-Al2O3 phase. Numerical simulations reveal the resistive hotspot-induced local heating in the pulsed current process enables the rapid transformation. Theoretical calculations show the topotactic transition (from γ- to δʹ- to α-Al2O3) is driven by their surface energy differences. The α-Al2O3 nanoparticles are sintered to nanograined ceramics with hardness superior to commercial alumina and approaching that of sapphire.
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    Sustainable valorization of asphaltenes via flash joule heating
    (AAAS, 2022) Saadi, M.A.S.R.; Advincula, Paul A.; Thakur, Md Shajedul Hoque; Khater, Ali Zein; Saad, Shabab; Shayesteh Zeraati, Ali; Nabil, Shariful Kibria; Zinke, Aasha; Roy, Soumyabrata; Lou, Minghe; Bheemasetti, Sravani N.; Bari, Md Abdullah Al; Zheng, Yiwen; Beckham, Jacob L.; Gadhamshetty, Venkataramana; Vashisth, Aniruddh; Kibria, Md Golam; Tour, James M.; Ajayan, Pulickel M.; Rahman, Muhammad M.
    The refining process of petroleum crude oil generates asphaltenes, which poses complicated problems during the production of cleaner fuels. Following refining, asphaltenes are typically combusted for reuse as fuel or discarded into tailing ponds and landfills, leading to economic and environmental disruption. Here, we show that low-value asphaltenes can be converted into a high-value carbon allotrope, asphaltene-derived flash graphene (AFG), via the flash joule heating (FJH) process. After successful conversion, we develop nanocomposites by dispersing AFG into a polymer effectively, which have superior mechanical, thermal, and corrosion-resistant properties compared to the bare polymer. In addition, the life cycle and technoeconomic analysis show that the FJH process leads to reduced environmental impact compared to the traditional processing of asphaltene and lower production cost compared to other FJH precursors. Thus, our work suggests an alternative pathway to the existing asphaltene processing that directs toward a higher value stream while sequestering downstream emissions from the processing.