Browsing by Author "Li, Yilun"
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Item Antibiofilm and antimicrobial functional membrane spacer(2021-06-08) Arnusch, Christopher John; Singh, Swatantra Pratap; Sargunaraj, Franklin; Oren, Yoram; Tour, James Mitchell; Li, Yilun; Rice University; B.G. Negev Technologies and Applications Ltd., at Ben-Gurion University; United States Patent and Trademark OfficeDisclosed herein methods for combating biofouling in a liquid, e.g. an aqueous medium by providing a surface coated with at least one laser-induced graphene (LIG) layer in said liquid medium. Particularly disclosed herein method and devices for treating water comprising passing a water stream through a membrane module equipped with at least one spacer coated with at least one layer of LIG, and optionally by applying an electric potential to the at least one LIG layer to achieve a bactericidal effect in the water stream. Specifically, disclosed herein a polymeric mesh suitable for use as a spacer in a membrane module in water treatment application, said mesh being at least partially coated with LIG.Item High-Performance Hydrogen Evolution from MoS2(1–x)P x Solid Solution(Wiley, 2016) Ye, Ruquan; Vicente, Paz Del Angel; Liu, Yuanyue; Arellano-Jimenez, Josefina; Peng, Zhiwei; Wang, Tuo; Li, Yilun; Yakobson, Boris I.; Wei, Su-Huai; Yacaman, Miguel Jose; Tour, James M.; Smalley Institute for Nanoscale Science and TechnologyA MoS2(1-x)Px solid solution (x = 0 to 1) is formed by thermally annealing mixtures of MoS2 and red phosphorus. The effective and stable electrocatalyst for hydrogen evolution in acidic solution holds promise for replacing scarce and expensive platinum that is used in present catalyst systems. The high performance originates from the increased surface area and roughness of the solid solution.Item High-yield single-step catalytic growth of graphene nanostripes by plasma enhanced chemical vapor deposition(Elsevier, 2018) Hsu, Chen-Chih; Bagley, Jacob D.; Teague, Marcus L.; Tseng, Wei-Shiuan; Yang, Kathleen L.; Zhang, Yiran; Li, Yiliang; Li, Yilun; Tour, James M.; Yeh, N.-C.; The Smalley-Curl Institute; NanoCarbon CenterWe report a single-step growth process of graphene nanostripes (GNSPs) by adding certain substituted aromatics (e.g., 1,2-dichlorobenzene) as precursors during the plasma enhanced chemical vapor deposition (PECVD). Without any active heating and by using low plasma power (≤60 W), we are able to grow GNSPs vertically with high yields up to (13 ± 4) g/m2 in 20 min. These GNSPs exhibit high aspect ratios (from 10:1 to >∼130:1) and typical widths from tens to hundreds of nanometers on various transition-metal substrates. The morphology, electronic properties and yields of the GNSPs can be controlled by the growth parameters (e.g., the species of seeding molecules, compositions and flow rates of the gases introduced into the plasma, plasma power, and the growth time). Studies of the Raman spectra, scanning electron microscopy images, ultraviolet photoelectron spectroscopy, transmission electron microscopy images, energy-dispersive x-ray spectroscopy and electrical conductivity of these GNSPs as functions of the growth parameters confirm high-quality GNSPs with electrical mobility ∼104 cm2/V-s. These results together with residual gas analyzer spectra and optical emission spectroscopy taken during PECVD growth suggest the important roles of both substituted aromatics and hydrogen plasma in the rapid vertical growth of GNSPs with large aspect ratios.Item Manganese deception on graphene and implications in catalysis(Elsevier, 2018) Ye, Ruquan; Dong, Juncai; Wang, Luqing; Mendoza-Cruz, Rubén; Li, Yilun; An, Peng-Fei; Yacamán, Miguel José; Yakobson, Boris I.; Chen, Dongliang; Tour, James M.Heteroatom-doped metal-free graphene has been widely studied as the catalyst for the oxygen reduction reaction (ORR). Depending on the preparation method and the dopants, the ORR activity varies ranging from a two-electron to a four-electron pathway. The different literature reports are difficult to correlate due to the large variances. However, due to the potential metal contamination, the origin of the ORR activity from “metal-free” graphene remains confusing and inconclusive. Here we decipher the ORR catalytic activities of diverse architectures on graphene derived from reduced graphene oxide. High angle annular dark field scanning transmission electron microscopy, X-ray absorption near edge structure, extended X-ray absorption fine structure, and trace elemental analysis methods are employed. The mechanistic origin of ORR activity is associated with the trace manganese content and reaches its highest performance at an onset potential of 0.94 V when manganese exists as a mononuclear-centered structure within defective graphene. This study exposes the deceptive role of trace metal in formerly thought to be metal-free graphene materials. It also provides insight into the design of better-performing catalyst for ORR by underscoring the coordination chemistry possible for future single-atom catalyst materials.Item Methods of fabricating laser-induced graphene and compositions thereof(2021-11-02) Tour, James M.; Chyan, Yieu; Arnusch, Christopher John; Singh, Swatantra Pratap; Li, Yilun; Luong X, Duy; Kittrell, Carter; Ye, Ruquan; Miller, Jordan; Kinstlinger, Ian; Cofer, Savannah; Rice University; Ben-Gurion University; United States Patent and Trademark OfficeMethods that expand the properties of laser-induced graphene (LIG) and the resulting LIG having the expanded properties. Methods of fabricating laser-induced graphene from materials, which range from natural, renewable precursors (such as cloth or paper) to high performance polymers (like Kevlar). With multiple lasing, however, highly conductive PEI-based LIG could be obtained using both multiple pass and defocus methods. The resulting laser-induced graphene can be used, inter alia, in electronic devices, as antifouling surfaces, in water treatment technology, in membranes, and in electronics on paper and food Such methods include fabrication of LIG in controlled atmospheres, such that, for example, superhydrophobic and superhydrophilic LIG surfaces can be obtained. Such methods further include fabricating laser-induced graphene by multiple lasing of carbon precursors. Such methods further include direct 3D printing of graphene materials from carbon precursors. Application of such LIG include oil/water separation, liquid or gas separations using polymer membranes, anti-icing, microsupercapacitors, supercapacitors, water splitting catalysts, sensors, and flexible electronics.Item Methods of fabricating laser-induced graphene and compositions thereof(2024-06-18) Tour, James M.; Chyan, Yieu; Arnusch, Christopher John; Singh, Swatantra Pratap; Li, Yilun; Luong X, Duy; Kittrell, Carter; Ye, Ruquan; Miller, Jordan; Kinstlinger, Ian; Cofer, Savannah; Rice University; B.G. Negev Technologies and Applications Ltd. at Ben-Gurion University; United States Patent and Trademark OfficeMethods that expand the properties of laser-induced graphene (LIG) and the resulting LIG having the expanded properties. Methods of fabricating laser-induced graphene from materials, which range from natural, renewable precursors (such as cloth or paper) to high performance polymers (like Kevlar). With multiple lasing, however, highly conductive PEI-based LIG could be obtained using both multiple pass and defocus methods. The resulting laser-induced graphene can be used, inter alia, in electronic devices, as antifouling surfaces, in water treatment technology, in membranes, and in electronics on paper and food Such methods include fabrication of LIG in controlled atmospheres, such that, for example, superhydrophobic and superhydrophilic LIG surfaces can be obtained. Such methods further include fabricating laser-induced graphene by multiple lasing of carbon precursors. Such methods further include direct 3D printing of graphene materials from carbon precurors. Application of such LIG include oil/water separation, liquid or gas separations using polymer membranes, anti-icing, microsupercapacitors, supercapacitors, water splitting catalysts, sensors, and flexible electronics.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 Rebar Graphene from Functionalized Boron Nitride Nanotubes(American Chemical Society, 2015) Li, Yilun; Peng, Zhiwei; Larios, Eduardo; Wang, Gunuk; Lin, Jian; Yan, Zheng; Ruiz-Zepeda, Francisco; José-Yacamán, Miguel; Tour, James M.; Richard E. Smalley Institute for Nanoscale Science and TechnologyThe synthesis of rebar graphene on Cu substrates is described using functionalized boron nitride nanotubes (BNNTs) that were annealed or subjected to chemical vapor deposition (CVD) growth of graphene. Characterization shows that the BNNTs partially unzip and form a reinforcing bar (rebar) network within the graphene layer that enhances the mechanical strength through covalent bonds. The rebar graphene is transferrable to other substrates without polymer assistance. The optical transmittance and conductivity of the hybrid rebar graphene film was tested, and a field effect transistor was fabricated to explore its electrical properties. This method of synthesizing 2D hybrid graphene/BN structures should enable the hybridization of various 1D nanotube and 2D layered structures with enhanced mechanical properties.Item Rebar hybrid materials and methods of making the same(2018-02-20) Tour, James M.; Yan, Zheng; Peng, Zhiwei; Hauge, Robert H.; Li, Yilun; Rice University; United States Patent and Trademark OfficeIn some embodiments, the present disclosure pertains to methods of forming a reinforcing material by: (1) depositing a first material onto a catalyst surface; and (2) forming a second material on the catalyst surface, where the second material is derived from and associated with the first material. In some embodiments, the first material includes, without limitation, carbon nanotubes, graphene nanoribbons, boron nitride nanotubes, chalcogenide nanotubes, carbon onions, and combinations thereof. In some embodiments, the formed second material includes, without limitation, graphene, hexagonal boron nitride, chalcogenides, and combinations thereof. In additional embodiments, the methods of the present disclosure also include a step of separating the formed reinforcing material from the catalyst surface, and transferring the separated reinforcing material onto a substrate without the use of polymers. Additional embodiments of the present disclosure pertain to reinforcing materials formed by the aforementioned methods.Item Rivet Graphene(American Chemical Society, 2016) Li, Xinlu; Sha, Junwei; Lee, Seoung-Ki; Li, Yilun; Ji, Yongsung; Zhao, Yujie; Tour, James M.; NanoCarbon CenterLarge-area graphene has emerged as a promising material for use in flexible and transparent electronics due to its flexibility and optical and electronic properties. The anchoring of transition metal nanoparticles on large-area single-layer graphene is still a challenge. Here, we report an in situ preparation of carbon nano-onion-encapsulated Fe nanoparticles on rebar graphene, which we term rivet graphene. The hybrid film, which allows for polymer-free transfer and is strong enough to float on water with no added supports, exhibits high optical transparency, excellent electric conductivity, and good hole/electron mobility under certain tensile/compressive strains. The results of contact resistance and transfer length indicate that the current in the rivet graphene transistor does not just flow at the contact edge. Carbon nano-onions encapsulating Fe nanoparticles on the surface enhance the injection of charge between rivet graphene and the metal electrode. The anchoring of Fe nanoparticles encapsulated by carbon nano-onions on rebar graphene will provide additional avenues for applications of nanocarbon-based films in transparent and flexible electronics.Item Synthesis, Structure and Properties of Various Carbon Nanomaterials(2017-07-24) Li, Yilun; Tour, James MCarbon nanomaterials can have a unique place in the field of nanotechnology thanks to their exceptional electrical, optical, chemical, and mechanical properties, and thus they have become promising for a diverse array of applications. More importantly, the properties of a specific carbon nanomaterial are often determined by the structure of the material itself, which further traces back to its synthesis. Accordingly, it is of great interest and importance to understand the relationship between the synthesis, structure, and properties of the carbon nanomaterials. My thesis begins with the chemical vapor deposition (CVD) synthesis and investigation of various graphene/nanotube (NT) hybrid structures in Chapter 1, including rebar graphene from functionalized boron nitride nanotubes (BNNTs), growing carbon nanotubes (CNTs) from both sides of graphene, and the selective growth and transfer of seamless three-dimensional (3D) graphene/CNT hybrids. Then, Chapter 2 discusses the fabrication of laser-induced graphene (LIG) materials in controlled atmospheres. Next, Chapter 3 describes the 3D printed graphene foams. Finally, Chapter 4 introduces biochar as a renewable source for high-performance CO2 porous carbon sorbent.Item Three-dimensional (3D) printing of graphene materials(2024-04-30) Tour, James M.; Sha, Junwei; Li, Yilun; Miller, Jordan; Kinstlinger, Ian; Cofer, Savannah; Chyan, Yieu; Rice University; United States Patent and Trademark OfficeThree-dimensional (3D) printing of graphene materials and methods and apparatuses for making same. In some embodiments, combined metal powder and carbon growth sources (such as powder Ni and sucrose) are utilized in the 3D printing process. In other embodiments, metal powders with binders (such as powder Ni and a polymer bases binder) are utilized in the 3D printing process. The metal in the resulting 3D printed composite material can then be etched or otherwise removed yielding the 3D printed graphene materials.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.