R-3 Repository :: Browsing by Author "Ye, Ruquan"

Browsing by Author "Ye, Ruquan"

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Accelerating multielectron reduction at CuxO nanograins interfaces with controlled local electric field
(Springer Nature, 2023) Guo, Weihua; Zhang, Siwei; Zhang, Junjie; Wu, Haoran; Ma, Yangbo; Song, Yun; Cheng, Le; Chang, Liang; Li, Geng; Liu, Yong; Wei, Guodan; Gan, Lin; Zhu, Minghui; Xi, Shibo; Wang, Xue; Yakobson, Boris I.; Tang, Ben Zhong; Ye, Ruquan
Regulating electron transport rate and ion concentrations in the local microenvironment of active site can overcome the slow kinetics and unfavorable thermodynamics of CO2 electroreduction. However, simultaneous optimization of both kinetics and thermodynamics is hindered by synthetic constraints and poor mechanistic understanding. Here we leverage laser-assisted manufacturing for synthesizing CuxO bipyramids with controlled tip angles and abundant nanograins, and elucidate the mechanism of the relationship between electron transport/ion concentrations and electrocatalytic performance. Potassium/OH− adsorption tests and finite element simulations corroborate the contributions from strong electric field at the sharp tip. In situ Fourier transform infrared spectrometry and differential electrochemical mass spectrometry unveil the dynamic evolution of critical *CO/*OCCOH intermediates and product profiles, complemented with theoretical calculations that elucidate the thermodynamic contributions from improved coupling at the Cu+/Cu2+ interfaces. Through modulating the electron transport and ion concentrations, we achieve high Faradaic efficiency of 81% at ~900 mA cm−2 for C2+ products via CO2RR. Similar enhancement is also observed for nitrate reduction reaction (NITRR), achieving 81.83 mg h−1 ammonia yield rate per milligram catalyst. Coupling the CO2RR and NITRR systems demonstrates the potential for valorizing flue gases and nitrate wastes, which suggests a practical approach for carbon-nitrogen cycling.
Bandgap engineering of carbon quantum dots
(2018-10-02) Tour, James M.; Ye, Ruquan; Metzger, Andrew; Stavinoha, Macy; Zheng, Yonghao; Rice University; United States Patent and Trademark Office
Embodiments of the present disclosure pertain to scalable methods of producing carbon quantum dots with desired bandgaps by the following steps: exposing a carbon source to an oxidant at a reaction temperature, where the exposing results in the formation of the carbon quantum dots; and selecting a desired size of the formed carbon quantum dots. In some embodiments, the selecting occurs by at least one of separating the desired size of the formed carbon quantum dots from other formed carbon quantum dots; selecting the reaction temperature that produces the desired size of the formed carbon quantum dots; and combinations of such steps. The desired size of carbon quantum dots can include a size range. The methods of the present disclosure can also include a step of purifying the formed carbon quantum dots prior to selecting a desired size.
Carbonaceous nanoparticles as conductivity enhancement additives to water-in-oil emulsions, oil-in-water emulsions and oil-based wellbore fluids
(2021-08-24) Tour, James M.; Ceriotti, Gabriel; Slesarev, Alexander; Ye, Ruquan; Price-hoelscher, Katherine; Bovet, Cara; Friedheim, Jim; Young, Steve; Rice University; M-I L.L.C.; United States Patent and Trademark Office
Various embodiments of the present disclosure provide methods of making wellbore fluids with enhanced electrical conductivities. In some embodiments, such methods comprise: (1) pre-treating a carbon material with an acid; and (2) adding the carbon material to the wellbore fluid. Further embodiments of the present disclosure pertain to wellbore fluids formed by the methods of the present disclosure. Additional embodiments of the present disclosure pertain to methods for logging a subterranean well by utilizing the aforementioned wellbore fluids.
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 Technology
The 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.
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 Technology
A 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.
Intrinsic and extrinsic defects in a family of coal-derived graphene quantum dots
(AIP Publishing LLC, 2015) Singamaneni, Srinivasa Rao; van Tol, Johan; Ye, Ruquan; Tour, James M.; Smalley Institute for Nanoscale Science and Technology
In this letter, we report on the high frequency (239.2 and 336 GHz) electron spin resonance (ESR) studies performed on graphene quantum dots (GQDs), prepared through a wet chemistry route from three types of coal: (a) bituminous, (b) anthracite, and (c) coke; and from non-coal derived GQDs. The microwave frequency-, power-, and temperature-dependent ESR spectra coupled with computer-aided simulations reveal four distinct magnetic defect centers. In bituminous- and anthracite-derived GQDs, we have identified two of them as intrinsic carbon-centered magnetic defect centers (a broad signal of peak to peak width = 697 (10−4 T), g = 2.0023; and a narrow signal of peak to peak width = 60 (10−4 T), g = 2.003). The third defect center is Mn2+ (6S5/2, 3d5) (signal width = 61 (10−4 T), g = 2.0023, Aiso = 93(10−4 T)), and the fourth defect is identified as Cu2+ (2D5/2, 3d9) (g⊥ = 2.048 and g‖ = 2.279), previously undetected. Coke-derived and non-coal derived GQDs show Mn2+ and two-carbon related signals, and no Cu2+ signal. The extrinsic impurities most likely originate from the starting coal. Furthermore, Raman, photoluminescence, and ESR measurements detected no noticeable changes in the properties of the bituminous GQDs after one year. This study highlights the importance of employing high frequency ESR spectroscopy in identifying the (magnetic) defects, which are roadblocks for spin relaxation times of graphene-based materials. These defects would not have been possible to probe by other spin transport measurements.
Laser-induced porous graphene films from commercial polymers
(Nature Publishing Group, 2014) Lin, Jian; Peng, Zhiwei; Liu, Yuanyue; Ruiz-Zepeda, Francisco; Ye, Ruquan; Samuel, Errol L.G.; Yacaman, Miguel Jose; Yakobson, Boris I.; Tour, James M.; Smalley Institute for Nanoscale Science and Technology
The cost effective synthesis and patterning of carbon nanomaterials is a challenge in electronic and energy storage devices. Here we report a one-step, scalable approach for producing and patterning porous graphene films with three-dimensional networks from commercial polymer films using a CO2 infrared laser. The sp3-carbon atoms are photothermally converted to sp2-carbon atoms by pulsed laser irradiation. The resulting laser-induced graphene (LIG) exhibits high electrical conductivity. The LIG can be readily patterned to interdigitated electrodes for in-plane microsupercapacitors with specific capacitances of >4 mF cm-2 and power densities of ~9 mW cm-2. Theoretical calculations partially suggest that enhanced capacitance may result from LIG's unusual ultra-polycrystalline lattice of pentagon-heptagon structures. Combined with the advantage of one-step processing of LIG in air from commercial polymer sheets, which would allow the employment of a roll-to-roll manufacturing process, this technique provides a rapid route to polymer-written electronic and energy storage devices.
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.
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 Office
Methods 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.
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 Office
Methods 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.
Methods of producing graphene quantum dots from coal and coke
(2018-03-20) Tour, James M.; Ye, Ruquan; Xiang, Changsheng; Lin, Jian; Peng, Zhiwei; Ceriotti, Gabriel; Rice University; United States Patent and Trademark Office
In some embodiments, the present disclosure pertains to methods of making graphene quantum dots from a carbon source (e.g., coal, coke, and combinations thereof) by exposing the carbon source to an oxidant. In some embodiments, the methods of the present disclosure further comprise a step of separating the formed graphene quantum dots from the oxidant. In some embodiments, the methods of the present disclosure further comprise a step of reducing the formed graphene quantum dots. In some embodiments, the methods of the present disclosure further comprise a step of enhancing a quantum yield of the graphene quantum dots. In further embodiments, the methods of the present disclosure also include a step of controlling the diameter of the formed graphene quantum dots by selecting the carbon source. In some embodiments, the formed graphene quantum dots comprise oxygen addends or amorphous carbon addends on their edges.
Nanomaterials in Diverse Dimensions: Synthesis, Properties and Applications
(2017-06-14) Ye, Ruquan; Tour, James M.
The discovery of C60 at Rice University has boosted the development of nanotechnology in the past decades. Materials at nanoscale possess distinct and excellent properties as compared to their bulk counterparts. Endowed with advantageous physical, chemical and electronic properties, nanomaterials have found promising applications in fields such as electronics, energy conversion, and energy storages. The performance of nanomaterial is usually correlated with its size, elemental constitution and hierarchical structure. My thesis begins with the investigation of zero dimensional nanomaterials in Chapter 1, which mainly focuses on the discovery and purification of graphene quantum dots (GQDs) from an abundant source: coal. I further explore of GQD applications as optical materials with tunable bandgap, and as electrocatalysts for the oxygen reduction reaction. Chapter 2 discusses the synthesis and applications of two dimensional nanomaterials, which includes the use of graphene-based hybrid and layered transition metal dichalcogenides in electrocatalysis. Finally, Chapter 3 studies the nanomaterials in three dimensional porous structures, namely laser-induced graphene. This chapter discloses the formation of hierarchical-structured graphene on commercial polymers and iii natural materials, and develops various applications in energy storage and energy conversion.

Browsing by Author "Ye, Ruquan"

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