Pengaruh Konsentrasi Sumber Karbon Terhadap Sifat PL Fosfor Boron Carbon Oxynitride(BCNO)

Kami berhasil mensintesis partikel fosfor BCNO dengan metode pemanasan sederhana menggunakan furnace. Kami menggunakan asam sitrat sebagai sumber karbon karena asam sitrat memiliki distribusi berat molekul yang seragam dan bersifat reaktif terhadap sumber boron dan sumber karbon. Variasi ntensitas pendaran dan puncak PL dapat diperoleh dengan memvariasikan konsentrasi sumber karbon dan temperatur sintesis. Temperatur sintesis yang kami gunakan yaitu 700oC, 750oC, 800oC, 850oC. Temperatur optimum untuk menghasilkan fosfor BCNO adalah pada temperatur 750oC. Partikel fosfor BCNO dikarakterisasi dengan menggunakan scanning electron microscope (SEM) dan PL spectra. SEM digunakan untuk melihat morfologi partikel fosfor BCNO sedangkan PL spectra digunakan untuk mengetahui intensitas pendaran dan puncak yang dihasilkan. Hasil karakterisasi dengan menggunakan scanning electron microscope (SEM) menunjukkan  bahwa morfologi fosfor BCNO berukuran mikron

Metal-Free Modified Boron Nitride for Enhanced CO2 Capture

Porous boron nitride is a new class of solid adsorbent with applications in CO2 capture. In order to further enhance the adsorption capacities of materials, new strategies such as porosity tuning, element doping and surface modification have been taken into account. In this work, metal-free modification of porous boron nitride (BN) has been prepared by a structure directing agent via simple heat treatment under N2 flow. We have demonstrated that textural properties of BN play a pivotal role in CO2 adsorption behavior. Therefore, addition of a triblock copolymer surfactant (P123) has been adopted to improve the pore ordering and textural properties of porous BN and its influence on the morphological and structural properties of pristine BN has been characterized. The obtained BN-P123 exhibits a high surface area of 476 m2/g, a large pore volume of 0.83 cm3/g with an abundance of micropores. More importantly, after modification with P123 copolymer, the capacity of pure CO2 on porous BN has improved by about 34.5% compared to pristine BN (2.69 mmol/g for BN-P123 vs. 2.00 mmol/g for pristine BN under ambient condition). The unique characteristics of boron nitride opens up new routes for designing porous BN, which could be employed for optimizing CO2 adsorption

Pengaruh Konsentrasi Sumber Karbon Terhadap Sifat PL Fosfor Boron Carbon Oxynitride(BCNO)

Kami berhasil mensintesis partikel fosfor BCNO dengan metode pemanasan sederhana menggunakan furnace. Kami menggunakan asam sitrat sebagai sumber karbon karena asam sitrat memiliki distribusi berat molekul yang seragam dan bersifat reaktif terhadap sumber boron dan sumber karbon. Variasi ntensitas pendaran dan puncak PL dapat diperoleh dengan memvariasikan konsentrasi sumber karbon dan temperatur sintesis. Temperatur sintesis yang kami gunakan yaitu 700oC, 750oC, 800oC, 850oC. Temperatur optimum untuk menghasilkan fosfor BCNO adalah pada temperatur 750oC. Partikel fosfor BCNO dikarakterisasi dengan menggunakan scanning electron microscope (SEM) dan PL spectra. SEM digunakan untuk melihat morfologi partikel fosfor BCNO sedangkan PL spectra digunakan untuk mengetahui intensitas pendaran dan puncak yang dihasilkan. Hasil karakterisasi dengan menggunakan scanning electron microscope (SEM) menunjukkan  bahwa morfologi fosfor BCNO berukuran mikron

Activated carbon materials with a rich surface chemistry prepared from L-cysteine amino acid

A series of activated carbon materials have been successfully prepared from a non-essential amino acid, such as L-cysteine. The synthesized carbons combine a widely developed porous structure (BET surface area up to 1000 m2/g) and a rich surface chemistry (mainly oxygen, nitrogen and sulphur functionalities). These surface functional groups are relatively stable even after a high temperature thermal treatment (O>N∼S). Experimental results show that these samples with a rich surface chemistry exhibit a significant improvement in their hydrophilic character. Although the role of the surface functional groups is less pronounced for the adsorption of non-polar molecules such as CO2, CH4 and C2H4, their adsorption at atmospheric pressure is to some extend conditioned by the characteristics of the adsorbent-adsorbate interactions. The synthesized carbons exhibit an excellent adsorption performance for CO2 (up to 3 mmol/g at 0°C). Furthermore, samples with a low activation degree exhibit molecular sieving properties with very promising CO2/CH4 (up to 4.5) and C2H4/CH4 (up to 6) selectivity ratios. These results anticipate that non-essential amino acids are a versatile platform to obtain carbon materials combining a tailored porous structure and rich multifunctional surface chemistry and with potential application for gas adsorption/separation processes.Authors would like to acknowledge financial support from the MINECO (Projects PID2019-108453GB-C21 and PCI2020-111968/ERANET-M/3D-Photocat) and NATO SPS program (Project G5683)

A Facile Synthesis and Photoluminescence Properties of Boron Carbon Oxynitride (BCNO)Phosphor Materials for Security Ink Application

A facile synthesis of rare-earth free using boron carbon oxynitride (BCNO) phosphor material for security ink has been investigate. BCNO were synthesize by low temperature microwave heating methods, with H3BO3, citric acid and urea to be used as boron,carbon and nitrogen source,respectively. Then, the BCNO nanocrystals were disperse in water-polymer based solution until they became evenly spreading and turn into security ink without rare earth metals. The photoluminescence (PL) and UV-Visible spectroscopy were use to characterize the optical properties of BCNO and the security ink. The characterization results showed that BCNO and the security ink had similar PL properties (PL Peak and PL Peak Intensity). In addition, the UV-Vis spectra proved that the security ink had electronic properties such as being semiconductors based phosphor materials. The results indicate that BCNO phosphor material can be potentially be developed as rare-earth free security inks, and other applications such as optoelectronic, white LED, lighting, etc

Carbon–GO Composites with Preferential Water versus Ethanol Uptake

The elimination of small amounts of water from alcohols is by no means a trivial issue in many practical applications like, for instance, the dehumidification of biocombustibles. The use of carbonaceous materials as sorbents has been far less explored than that of other materials because their hydrophobic character has typically limited their water uptake. Herein, we designed a synthetic process based on the use of eutectic mixtures that allowed the homogeneous dispersion of graphene oxide (GO) in the liquid containing the carbon precursor, e.g., furfuryl alcohol. Thus, after polymerization and a subsequent carbonization process, we were able to obtain porous carbon–GO composites where the combination of pore diameter and surface hydrophilicity provided a remarkable capacity for water uptake but extremely low methanol and ethanol uptake along the entire range of relative pressures evaluated in this work. Both the neat water uptake and the uptake difference between water and either methanol or ethanol of our carbon–GO composites were similar or eventually better than the uptake previously reported for other materials, also exhibiting preferential water-to-alcohol adsorption, e.g., porous coordination polymers, metal–organic frameworks, polyoxometalates, and covalent two-dimensional nanosheets embedded in a polymer matrix. Moreover, water versus alcohol uptake was particularly remarkable at low partial pressures in our carbon–GO composites.This work was supported by MINECO/FEDER (Project Numbers MAT2015-68639-R, MAT2016-80285-P, and RTI2018-097728-B-I00). L.Z.G. acknowledges the Chinese Scholarship Council for a PhD research fellowship (CSC No. 201608330266). C.C.-C. acknowledges UA for a research contract

New emerging rare-earth free yellow emitting 2D BCNO nanophosphor for white light emitting diodes

We have demonstrated a new emerging rare-earth free highly-efficient two dimensional (2D) boron carbon oxynitride (BCNO) yellow emitting nanophosphor with high quantum efficiency for white light emitting diode (WLED) devices. This BCNO nanophosphor exhibits 2D layered structures analogous to hexagonal BN phase. Further, the EELS and XPS results confirm the nanophosphor consisted of B, C, N and O elements. The BCNO nanophosphor shows a broad highly intense yellow emission band centered at 580 nm corresponding to 470 nm excitation wavelength with a quantum efficiency approaching 89%. This novel nanophosphor with strong emission has subsequently been integrated to chip on board (CoB) based blue LEDs in order to fabricate WLEDs devices with a color rendering index of 92. Low color temperature (4899) and better CIE color coordinates (x = 0.3496, y = 0.3679) of a fabricated WLEDs device supports a 2D BCNO nanophosphor that could be an exceptional choice for CoB based WLEDs. Hence, our method provides a facile synthesis of rare-earth free 2D lightweight BCNO nanophosphor and its integration with CoB based blue LEDs for next generation advanced solid state white light applications

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Department of Energy Engineering (Energy Engineering)With the demand to overcome the issues concerning environmental pollution of fossil fuel in large-scale system and various fields, numerous efforts have been devoted toward a design of rational energy storage system (ESS) in order to substitute present energy source. While lots of systems are suggested, lithium-ion batteries (LIBs) have been attracted as one of the promising ESS among various storage devices. Existing one which consists of a graphite anode unfortunately have the trouble to fulfilling required condition such as high power and energy density. Thus, new type of anode materials has been developed to achieve mentioned specifications. As possible candidates, silicon (Si) and germanium (Ge) have been emerged owing to their high gravimetric/volumetric capacity and low operating voltage. Nevertheless, those materials remain under challenge level because inferior electronic properties have the limit to catch high power density and unexpected volume expansion on a lithiation process into materials, resulting in the electrode failure and capacity decay where factors influence safety and stability issues in LIBs system. Here, we introduce approaches through dimensional manipulation to proceed. Overall synthetic processes are focused on versatile method, a possibility of mass production and evaluation methods obviously demonstrate intrinsic/extrinsic characteristic ways. With in situ microscopic/electrochemical techniques, specific properties and electrochemical reaction mechanism of synthesized materials are clearly unveiled to facilitate power density enhancement and volume change suppression. In Chapter II, we present zero-dimensional (0D) carbon wrapped-hollow Si microparticles which possess porous shell structure from various silica source regardless of their shape. Sequent top-down and bottom-up processes fabricate uniform 0D Si and a key factor for unique formation mechanism is verified through ex situ characterization and simulation results. In electrochemical view, creating cavities in a core and pores in the shell alleviate volume expansion and enable short ion-diffusion length. Surface carbon layer additionally provide fast electron movement to guarantee stable and considerable power density. Besides, in situ transmission electron microscopic (TEM) demonstrate the stability of morphological structure on charge/discharging cycle. In Chapter III, we design one-dimensional (1D) Ge/zinc (Zn)-based nanofibers. Homogeneous Ge/Zn nanofibers via electrospinning method and solid-gas reduction reaction own atomic-level distribution of each element. Well-dispersive metallic Zn in Ge nanofiber could effectively improve electronic conductivity/volumetric stability and nanosized structure also features facile ion transport and stress release by volume expansion on electrochemical cycles. In situ TEM/electrochemical impedance spectroscopy (EIS) deeply investigate the critical role of ionic bond of Zn element in Ge nanofibers. In Chapter IV, we introduce additional 1D Ge nanofibers, which feature numerous sizes of pores in whole morphological structure. Intrinsic metal oxide characters based on Ellingham diagram enable to carve heterogenous pore in and out of nanofibers. This structure shows stable electrochemical cyclability without a large volume expansion. Further, we confirm the unique behavior of Ge, called memory effect in LIBs. In situ TEM characterization supports that numerous pores work as volume buffer sites and keep spatial reversibility on charge/discharge cycles. In Chapter V, we finally suggest synthetic method of three-dimensional (3D) porous Ge clusters from zeotype-borogermanate microcubes, artificial Ge-rich zeolite. This starting material is prepared in a large quantity through a simple hydrothermal process as followed by sequential thermal and etching treatment to produce 3D porous Ge. As-fabricated product interestingly behaves like a pseudocapacitance exhibiting fast electrochemical kinetics. Further, the as-formed pores build up stable solid electrolyte interphase (SEI) layer on the surface for prolonged cycles, improving cycle stability. In Chapter VI, we briefly provide the insight for the correlation of the dimensions and electrochemical properties toward advanced lithium storage system. To handle unsettled issues in large-scale lithium batteries, it is essential to look around the overall circumstances to match the specific purpose.clos

Synthesis and modification of porous boron nitride materials for application in carbon dioxide capture

Global warming, which is often confused with “climate change”, can cause longlasting, irreversible, catastrophic and far-reaching effects on the earth and the lives of the future generations. There is a unanimous agreement that global warming is mainly due to human activities and above all, burning fossil fuels for industrial applications and emission of CO2 as one of the major contributors of global warming. To mitigate the amount of CO2 emission and to offset its effect, the governments around the world have united to take necessary actions in an effective and efficient way by a variety of policy changes and adoption of technologies such as carbon capture and storage. For instance, the UK government has set out measures to tackle climate change with a plan for the UK to be a pioneering economy in the world towards a zero-emission economy by 2050. Among the technologies used for carbon capture, those derived from solid sorbents for CO2 capture attract growing interest in industrial applications. The popularity of using these technologies is attributed to their lower energy penalty, high selectivity, recyclability and ease of manufacturing. Developments of new materials with low cost is fundamental, even though numerous solid sorbents have been examined for CO2 capture to date. Porous boron nitride (BN) has been recognised as a promising alternative to be used in carbon adsorption process due to its unique advantages including its bond polarity, tuneability and high thermal and chemical stabilities. So far, a systematic understanding of how its distinctive properties (pore structure and chemistry) contributes to capture carbon dioxide is still lacking. To develop a favourable porous BN, further work is required to establish the viability of these materials as cost-effective adsorbents. This research presents synthesis and modification strategies of porous BN and a characterisation of the material for carbon capture application. Various synthesis conditions have been developed to obtain high surface area (>700 m2/g) pristine BN material via template free method. The study pursued two distinct strategies to modify pristine porous BN, aiming to enhance its CO2 adsorption performance. Firstly, a focus on controlling the pure BN porosity has been implemented by tuning with a polymeric surfactant as non-metal modification approach. The capacity of pure CO2 on nonmetal modified porous BN has been enhanced by about 34.5% compared to pristine BN in ambient conditions. The study highlights the significant role of porosity/pore size of BN for CO2 adsorption. Secondly, a novel approach has been implemented for modifying pore structure and surface chemistry of pristine BN by introduction of Ni (II) into BN framework. The pure CO2 capture experiment has been assessed, considering three different temperatures and the results confirmed that the basic sites on porous BN contribute to its ability to adsorb more CO2 relative to pure BN. The method has been validated as a feasible route to improve porous BN performance in CO2 adsorption process even at realistic flue gas temperatures (above 298 K). Finally, the stability and reusability of pristine BN samples with various porosity and chemistry have been examined over the eight adsorption-desorption cycles. Overall, this dissertation demonstrated that porous BN materials possess a combination of desirable properties with flexibility for functionalisation and lower regeneration energy. Thus, it can be considered as an effective adsorbent for future large-scale carbon capture technologies

Using porous boron nitride in adsorption-based processes: investigation of material challenges and opportunities

In 2016, industrial separation processes accounted for 10-15% of the global energy consumption. This striking figure has urged the scientific community to continue developing new materials and technologies to significantly reduce global emissions in industry, for example in the field of adsorption processes. In light of this, porous boron nitride (BN) has gradually appeared as a promising adsorbent owing to its tunable chemistry and porosity, which a priori make it adaptable for various applications. However, research on porous BN remains at laboratory scale due to a lack of understanding of its formation mechanism. Furthermore, the material has displayed hydrolytic instability, which is an issue due to the presence of moisture in most industrial settings. Finally, the use of porous BN has mainly been focusing on molecular separations, but little is known about its potential for other adsorption-based applications, such as thermal energy storage. In this thesis, I first investigated the formation mechanism of porous BN to shed light on the critical steps of its synthesis. Considering a wide range of separations, I then searched new ways of enhancing its hydrolytic stability via surface functionalization. I developed two methods involving organosilane grafting, which produced porous BN adsorbents with enhanced moisture resistance and adequate CO2/N2 selectivity in the context of CO2 capture. Finally, I expanded the range of possible applications using porous BN and researched its potential for thermochemical energy storage, which has recently emerged as a key technology to mitigate CO2 emissions. I prepared BN-based adsorbents with various structural and thermal properties, allowing to understand how material properties affect the performance in thermochemical energy storage via adsorption. Overall, this thesis presents new knowledge on porous BN and explores the opportunities and challenges associated with its unique properties in the context of adsorption-based applications, in particular CO2/N2 separation and thermochemical energy storage.Open Acces