Browsing by Author "Jalilov, Almaz S."
Now showing 1 - 6 of 6
Results Per Page
Sort Options
Item High Performance Electrocatalytic Reaction of Hydrogen and Oxygen on Ruthenium Nanoclusters(American Chemical Society, 2017) Ye, Ruquan; Liu, Yuanyue; Peng, Zhiwei; Wang, Tuo; Jalilov, Almaz S.; Yakobson, Boris I.; Wei, Su-Huai; Tour, James M.; Smalley Institute for Nanoscale Science and TechnologyThe development of catalytic materials for the hydrogen oxidation, hydrogen evolution, oxygen reduction or oxygen evolution reactions with high reaction rates and low overpotentials are key goals for the development of renewable energy. We report here Ru(0) nanoclusters supported on nitrogen-doped graphene as high-performance multifunctional catalysts for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), showing activities similar to that of commercial Pt/C in alkaline solution. For HER performance in alkaline media, sample Ru/NG-750 reaches 10 mA cm–2 at an overpotential of 8 mV with a Tafel slope of 30 mV dec–1. The high HER performance in alkaline solution is advantageous because most catalysts for ORR and oxygen evolution reaction (OER) also prefer alkaline solution environment whereas degrade in acidic electrolytes. For ORR performance, Ru/NG effectively catalyzes the conversion of O2 into OH– via a 4e process at a current density comparable to that of Pt/C. The unusual catalytic activities of Ru(0) nanoclusters reported here are important discoveries for the advancement of renewable energy conversion reactions.Item Hydrated porous materials for selective CO2 capture(2019-03-19) Tour, James M.; Jalilov, Almaz S.; Rice University; United States Patent and Trademark OfficeIn some embodiments, the present disclosure pertains to methods of capturing CO2 from an environment by hydrating a porous material with water molecules to the extent thereby to define a preselected region of a plurality of hydrated pores and yet to the extent to allow the preselected region of a plurality of pores of the porous material to uptake gas molecules; positioning the porous material within a CO2 associated environment; and capturing CO2 by the hydrated porous material. In some embodiments, the pore volume of the hydrated porous material includes between 90% and 20% of the pre-hydrated pore volume to provide unhydrated pore volume within the porous material for enhanced selective uptake of CO2 in the CO2 associated environment. In some embodiments, the step of capturing includes forming CO2-hydrates within the pores of the porous material, where the CO2.nH2O ratio is n<4.Item Perylene Diimide as a Precise Graphene-like Superoxide Dismutase Mimetic(American Chemical Society, 2017) Jalilov, Almaz S.; Nilewski, Lizanne G.; Berka, Vladimir; Zhang, Chenhao; Yakovenko, Andrey A.; Wu, Gang; Kent, Thomas A.; Tsai, Ah-Lim; Tour, James M.; The NanoCarbon CenterHere we show that the active portion of a graphitic nanoparticle can be mimicked by a perylene diimide (PDI) to explain the otherwise elusive biological and electrocatalytic activity of the nanoparticle construct. Development of molecular analogues that mimic the antioxidant properties of oxidized graphenes, in this case the poly(ethylene glycolated) hydrophilic carbon clusters (PEG–HCCs), will afford important insights into the highly efficient activity of PEG–HCCs and their graphitic analogues. PEGylated perylene diimides (PEGn–PDI) serve as well-defined molecular analogues of PEG–HCCs and oxidized graphenes in general, and their antioxidant and superoxide dismutase-like (SOD-like) properties were studied. PEGn–PDIs have two reversible reduction peaks, which are more positive than the oxidation peak of superoxide (O2•–). This is similar to the reduction peak of the HCCs. Thus, as with PEG–HCCs, PEGn–PDIs are also strong single-electron oxidants of O2•–. Furthermore, reduced PEGn–PDI, PEGn–PDI•–, in the presence of protons, was shown to reduce O2•– to H2O2 to complete the catalytic cycle in this SOD analogue. The kinetics of the conversion of O2•– to O2 and H2O2 by PEG8–PDI was measured using freeze-trap EPR experiments to provide a turnover number of 133 s–1; the similarity in kinetics further supports that PEG8–PDI is a true SOD mimetic. Finally, PDIs can be used as catalysts in the electrochemical oxygen reduction reaction in water, which proceeds by a two-electron process with the production of H2O2, mimicking graphene oxide nanoparticles that are otherwise difficult to study spectroscopically.Item Porous carbon materials for CO2 separation in natural gas(2017-10-03) Tour, James M.; Schipper, Desmond E.; Hwang, Chih-chau; Tour, Josiah; Jalilov, Almaz S.; Ruan, Gedeng; Li, Yilun; Rice University; United States Patent and Trademark OfficeIn some embodiments, the present disclosure pertains to materials for use in CO2 capture in high pressure environments. In some embodiments, the materials include a porous carbon material containing a plurality of pores for use in a high pressure environment. Additional embodiments pertain to methods of utilizing the materials of the present disclosure to capture CO2 from various environments. In some embodiments, the materials of the present disclosure selectively capture CO2 over hydrocarbon species in the environment.Item Porous carbon materials for CO2 separation in natural gas(2017-03-21) Tour, James M.; Schipper, Desmond E.; Hwang, Chih-chau; Tour, Josiah; Jalilov, Almaz S.; Ruan, Gedeng; Li, Yilun; Rice University; United States Patent and Trademark OfficeIn some embodiments, the present disclosure pertains to materials for use in CO2 capture in high pressure environments. In some embodiments, the materials include a porous carbon material containing a plurality of pores for use in a high pressure environment. Additional embodiments pertain to methods of utilizing the materials of the present disclosure to capture CO2 from various environments. In some embodiments, the materials of the present disclosure selectively capture CO2 over hydrocarbon species in the environment.Item Ultra-High Surface Area Activated Porous Asphalt for CO2 Capture through Competitive Adsorption at High Pressures(Wiley, 2017) Jalilov, Almaz S.; Li, Yilun; Tian, Jian; Tour, James M.; NanoCarbon CenterThis study reports an improved method for activating asphalt to produce ultra-high surface area porous carbons. Pretreatment of asphalt (untreated Gilsonite, uGil) at 400 °C for 3 h removes the more volatile organic compounds to form pretreated asphalt (uGil-P) material with a larger fraction of higher molecular weight π-conjugated asphaltenes. Subsequent activation of uGil-P at 900 °C gives an ultra-high surface area (4200 m2 g−1) porous carbon material (uGil-900) with a mixed micro and mesoporous structure. uGil-900 shows enhanced room temperature CO2 uptake capacity at 54 bar of 154 wt% (35 mmol g−1). The CH4 uptake capacity is 37.5 wt% (24 mmol g−1) at 300 bar. These are relevant pressures in natural gas production. The room temperature working CO2 uptake capacity for uGil-900 is 19.1 mmol g−1 (84 wt%) at 20 bar and 32.6 mmol g−1 (143 wt%) at 50 bar. In order to further assess the reliability of uGil-900 for CO2 capture at elevated pressures, the authors study competitive sorption of CO2 and CH4 on uGil-900 at pressures from 1 to 20 bar at 25 °C. CO2/CH4 displacement constants are measured at 2 to 40 bar, and found to increase significantly with pressure and surface area.