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101. Multiagent Learning through Neuroevolution

Author

Miikkulainen, Risto, primary, Feasley, Eliana, additional, Johnson, Leif, additional, Karpov, Igor, additional, Rajagopalan, Padmini, additional, Rawal, Aditya, additional, and Tansey, Wesley, additional

Published
2012
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107. A Comparison between the Characteristics of a Biochar-Npk Granule and a Commercial Npk Granule for Application in the Soil

Author

Tahery, Sara, primary, Munroe, Paul, additional, Marjo, Christopher E., additional, Rawal, Aditya, additional, Horvat, Joseph, additional, Mohammed, Mohanad, additional, Webber, J. Beau W., additional, Arns, Ji-Youn, additional, Arns, Christoph H., additional, Pan, Genxing, additional, Ronjun, Bian, additional, and Joseph, Stephen, additional

Published
2021
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110. Nanostructured LiMnO2 with Li3PO4 Integrated at the Atomic Scale for High-Energy Electrode Materials with Reversible Anionic Redox

Author

Sawamura, Miho, primary, Kobayakawa, Sho, additional, Kikkawa, Jun, additional, Sharma, Neeraj, additional, Goonetilleke, Damian, additional, Rawal, Aditya, additional, Shimada, Nanaka, additional, Yamamoto, Kentaro, additional, Yamamoto, Rina, additional, Zhou, Yingying, additional, Uchimoto, Yoshiharu, additional, Nakanishi, Koji, additional, Mitsuhara, Kei, additional, Ohara, Koji, additional, Park, Jiwon, additional, Byon, Hye Ryung, additional, Koga, Hiroaki, additional, Okoshi, Masaki, additional, Ohta, Toshiaki, additional, and Yabuuchi, Naoaki, additional

Published
2020
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116. Improving the acidic stability of zeolitic imidazolate frameworks by bio-functional molecules

Author

Gao, Song, Hou, Jingwei, Deng, Zeyu, Wang, Tiesheng, Beyer, Sebastian, Buzanich, Ana Guilherme, Richardson, Joseph J, Rawal, Aditya, Seidel, Robert, Zulkifli, Muhammad Yazid, Li, Weiwei, Bennett, Thomas, Cheetham, Anthony, Liang, Kang, Chen, Vicki, Wang, Tiesheng [0000-0001-7587-7681], Li, Weiwei [0000-0001-5781-5401], Bennett, Thomas [0000-0003-3717-3119], and Apollo - University of Cambridge Repository

Subjects
3402 Inorganic Chemistry, 34 Chemical Sciences
Abstract

Zeolitic imidazolate frameworks (ZIFs) have been widely investigated for separation, gas adsorption, catalysis and biotechnology. Their practical application, however, can be hampered by their structural instability in humid acidic conditions. Here, guided by density functional theory calculations, we demonstrate that the acidic stability of two polymorphic ZIFs (i.e. ZIF-8 and ZIF-L) can be enhanced by incorporating functional groups on polypeptides or DNA. A range of complementary synchrotron investigations into the local chemical structure and bonding environment suggest that the enhanced acidic stability arises from the newly-established coordinative interactions between the Zn centers and the inserted carboxylate (for polypeptides) or phosphate (for DNA) groups, which both have lower pKas than the imidazolate ligand. With functional biomolecular homologues (i.e. enzymes), we demonstrate a symbiotic stability reinforcement effect, i.e. the encapsulated biomolecules stabilize the ZIF matrix while the ZIF exoskeleton protects the enzyme from denaturation.

Published
2019
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119. Core–Shell NaBH4@Na2B12H12 Nanoparticles as Fast Ionic Conductors for Sodium-Ion Batteries.

Author

Luo, Xiaoxuan, Rawal, Aditya, Salman, Muhammad Saad, and Aguey-Zinsou, Kondo-Francois

Abstract

Herein, we report on a method to engineer a conductive interface to promote high Na+ ionic conductivity in NaBH4. By controlled reaction with B2H6, the ionic conductivity of NaBH4 is enhanced by 5 orders of magnitude at room temperature. The origin of the enhanced conductivity is believed to be the result of the formation of a Na2B12H12 layer on the surface of α-NaBH4 particles. The resultant NaBH4@Na2B12H12 heterostructure exhibits a high ionic conductivity of 10–4 S cm–1 at 115 °C superior to that of pristine NaBH4 and shows the potential to act as a solid-state electrolyte for all Na solid-state batteries. [ABSTRACT FROM AUTHOR]

Published
2022
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120. High-voltage and highly reversible redox chemistry of in situcross-linked polydiphenylamine as an aqueous zinc battery cathode

Author

Shang, Yuan, Rawal, Aditya, and Kundu, Dipan

Abstract

Organic redox-active materials are promising electrode candidates for the next generation of rechargeable batteries owing to their versatile redox chemistry, sustainability, and potential low cost. Here, we present polydiphenylamine as a moderately high-voltage (1.25 V vs. Zn) and highly reversible organic cathode for aqueous zinc batteries. As revealed by cyclic voltammetry and spectroscopic analysis, the chemical oxidation–derived diphenylamine dimer electrochemically transforms into a cross-linked polymeric material during the first electrochemical oxidation (charge), which then operates by p-doping/dedoping redox of the amine center and a pseudocapacitor-like solid-state charge storage mechanism during the subsequent discharge-charge cycles. With an 80 wt% active loading, the polymer cathode delivers a specific capacity of 138 mAh/g at 100 mA/g, with 73% retention over 1000 cycles at a 99.8% Coulombic efficiency. Excellent rate capability is evidenced by 87 mAh/g capacity at 400 mA/g and highly stable cycling of over 1200 cycles under variable current rates. Facile one-step synthesis, fast charge storage kinetics, and attractive electrochemical performance establish polydiphenylamine as a notable organic cathode candidate for aqueous zinc batteries.

Published
2024
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126. Electroactive Co(iii) salen metal complexes and the electrophoretic deposition of their porous organic polymers onto glassy carbon

Author

Solomon, Marcello B, Rawal, Aditya, Hook, James M, Cohen, Seth M, Kubiak, Clifford P, Jolliffe, Katrina A, and D'Alessandro, Deanna M

Subjects
Chemical Sciences
Abstract

This paper reports the CO2 electroreduction properties of three bis-bromo Co(iii) salen metal complexes and their Porous Organic Polymers (POPs) as a platform for using the salen core as a multi-electron reducing agent. Although Co(iii) salen metal complexes have been studied extensively for their chemical catalysis with CO2, their electrochemical behaviour, particularly their reduction, in the presence of CO2 is much less explored. The discrete Co(iii) complexes enabled the reduction of CO2 to CO in faradaic efficiencies of up to 20%. The reductive electrochemical processes of Co(iii) salen complexes are relatively unknown; therefore, the mechanism of reduction for the complexes was investigated using IR and UV-Vis-NIR spectroelectrochemical (SEC) techniques. The discrete bis-bromo salen complexes were incorporated into POPs with tris-(p-ethynyl)-triphenylamine as a co-ligand and were characterised using solid state NMR, IR, UV-Vis-NIR and Field Emission Scanning Electron Microscopy (FE-SEM). The POP materials were electrophoretically deposited onto glassy carbon under milder conditions than those previously reported in the literature. Direct attachment of the POP materials to glassy carbon enabled improved solid state electrochemical analysis of the samples. The POP materials were also analysed via SEC techniques, where a Co(ii/i) process could be observed, but further reductions associated with the imine reduction compromised the stability of the POPs.

Published
2018

128. Shock Exfoliation of Graphene Fluoride in Microwave

Author

Wu, Sicheng, primary, Mo, Jingxin, additional, Zeng, Yachao, additional, Wang, Yuan, additional, Rawal, Aditya, additional, Scott, Jason, additional, Su, Zhen, additional, Ren, Wenhao, additional, Chen, Sheng, additional, Wang, Kaixuan, additional, Chen, Wei, additional, Zhang, Yongzhi, additional, Zhao, Chuan, additional, and Chen, Xianjue, additional

Published
2019
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131. Application of low-field, 1H/13C high-field solution and solid state NMR for characterisation of oil fractions responsible for wettability change in sandstones

Author

Shikhov, Igor ; https://orcid.org/0000-0002-9537-5192, Thomas, Donald S ; https://orcid.org/0000-0002-0582-2084, Rawal, Aditya ; https://orcid.org/0000-0002-5396-1265, Yao, Yin, Gizatullin, Bulat, Hook, James M ; https://orcid.org/0000-0002-1185-7320, Stapf, Siegfried, Arns, Christoph ; https://orcid.org/0000-0003-1721-3996, Shikhov, Igor ; https://orcid.org/0000-0002-9537-5192, Thomas, Donald S ; https://orcid.org/0000-0002-0582-2084, Rawal, Aditya ; https://orcid.org/0000-0002-5396-1265, Yao, Yin, Gizatullin, Bulat, Hook, James M ; https://orcid.org/0000-0002-1185-7320, Stapf, Siegfried, and Arns, Christoph ; https://orcid.org/0000-0003-1721-3996

Abstract

Asphaltene adsorption on solid surfaces is a standing problem in petroleum industry. It has an adverse effect on reservoir production and development by changing rock wettability, plugging pore throats, and affects oil transport through pipelines. Asphaltene chemistry constitutes important part of the ageing process as part of petrophysical studies and core analysis. The mechanisms and contribution of various oil components to adsorption processes is not fully understood. To investigate the kinetics of the ageing process and address the relative contribution of different oil components, we prepared three sets of sandstone core plugs aged in different oil mixtures over various time intervals. Cores were then re-saturated with decane to evaluate their wetting state using low-field NMR relaxometry by monitoring a change of surface relaxivity. Adsorbed deposits were then extracted from cores for solution-state NMR analysis. Their 1H and 1H-13C correlation spectra obtained using heteronuclear single quantum coherence (HSQC) technique were matched to spectra of four SARA (saturates, aromatics, resins and asphaltenes) components of oil mixtures to deduce components of deposits and inter-component interactions. We notice that wettability reversal of rock is inversely proportional to initial asphaltene concentration. Analysis of deposits reveals an increase in their aliphatic content over ageing time, which is accompanied by a change of the morphology of the pore space due to cluster aggregates forming a network. Results suggest that the ageing process in respect to the wetting state of rock samples consists of three distinctive stages: (i) an early-time period, when the fraction of most polar asphaltenes creates a discontinuous layer corresponding to mixed-wet state; (ii) an intermediate-time interval, at which the full grain coverage may be achieved (at favourable chemical environment) corresponding to strong oil-wetting; (iii) a late-time stage, where intense macro-aggreg

Published
2019

132. Modulating catalytic oxygen activation over Pt–TiO2/SiO2catalysts by defect engineering of a TiO2/SiO2supportElectronic supplementary information (ESI) available. See DOI: 10.1039/d1cy02037d

Author

Saputera, Wibawa Hendra, Tan, Tze Hao, Lovell, Emma C., Rawal, Aditya, Aguey-Zinsou, Kondo-Francois, Friedmann, Donia, Amal, Rose, and Scott, Jason A.

Abstract

Binary TiO2/SiO2oxides were synthesized viaflame spray pyrolysis as supports for a Pt catalyst. The effect of the mole ratio of the silica on the catalyst characteristics and catalytic performance for formic acid oxidation under dark (non-illuminated) conditions and following UV light pre-treatment was examined. As the TiO2 : SiO2ratio increased, the following was observed: (i) the specific surface area gradually decreased from ∼325 m2g−1to ∼50 m2g−1; (ii) the crystal structure was transformed from amorphous titania to crystalline anatase phase; (iii) the defect sites comprising Ti3+, E′ centres, and non-bridging oxygen hole centers (NBOHCs) were maximum at a TiO2 : SiO2ratio of 1 : 2 (Pt/1TiO2–2SiO2); and (iv) oxygen adsorbed on the Pt deposit surface (PtOads) was a maximum for Pt/1TiO2–2SiO2. The catalytic activity of Pt–TiO2/SiO2was strongly dependent on the TiO2/SiO2ratio and was further enhanced by hydrogenation and UV light pre-treatment. In line with the greatest presence of support-based defects and PtOadsspecies, the Pt/1TiO2–2SiO2catalyst exhibited the highest catalytic rate following UV light pre-treatment. The simultaneously boosted presence of PtOadsand defect sites (comprising Ti3+, E′ centers, and NBOHC) on the Pt–TiO2/SiO2catalysts following UV-light pre-treatment is proposed as the origin of the enhanced formic acid oxidation reaction.

Published
2022
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141. Investigation of K modified P2 Na0.7Mn0.8Mg0.2O2 as a cathode material for sodium-ion batteries

Author

Sehrawat, Divya, primary, Cheong, Soshan, additional, Rawal, Aditya, additional, Glushenkov, Alexey M., additional, Brand, Helen E. A., additional, Cowie, Bruce, additional, Gonzalo, Elena, additional, Rojo, Teófilo, additional, Naeyaert, Pierre J. P., additional, Ling, Chris D., additional, Avdeev, Maxim, additional, and Sharma, Neeraj, additional

Published
2019
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143. S-Mg2(dobpdc): a metal–organic framework for determining chirality in amino acids.

Author

Tay, Hui Min, Rawal, Aditya, and Hua, Carol

Subjects
*AMINO acids, *PROLINE, *METAL-organic frameworks, *ESSENTIAL amino acids, *CHIRALITY, *ALANINE
Abstract

Chirality is a key aspect of amino acids and is essential for life. Here, a chiral metal–organic framework, S-Mg2dobpdc, is used to determine the chirality of three BOC protected amino acids (alanine, valine and proline) by 13C solid-state NMR with chemical shift differences of up to 1.3 ppm observed between enantiomers. The chiral sensitivity persists upon in situ deprotection of the amino acids by thermolysis of the BOC group. [ABSTRACT FROM AUTHOR]

Published
2020
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145. Evidence of phase coexistence in hydrothermally synthesized K0.5Na0.5NbO3 nanofibers.

Author

Ghasemian, Mohammad B., Rawal, Aditya, Shahrbabaki, Zahra, Zhang, Qi, Lu, Teng, Liu, Yun, and Wang, Danyang

Abstract

The argument of phase coexistence in the lead-free piezoelectric perovskite K0.5Na0.5NbO3 (KNN) has led to significant discrepancies in the interpretation of its exact crystalline structure in the literature. In this work, the structural details of hydrothermally prepared KNN nanofibres and microcubes were investigated by a combination of high resolution transmission electron microscopy (TEM), solid-state 23Na and 93Nb nuclear magnetic resonance (NMR) spectroscopy and two-dimensional 23Na 3QMAS NMR. Although powder X-ray diffraction yielded an average orthorhombic structure for both morphologies, high resolution TEM revealed mixed phases of orthorhombic (O) and monoclinic (M) symmetry with a growth direction of [001] and [110], respectively, in individual KNN nanofibres. Consistent with the TEM analysis, solid-state 23Na NMR indicated a distribution of multiple Na sites in the KNN nanofibers, which were not observed in the KNN microcubes. This study provided microscopic evidence of phase coexistence in KNN nanofibers and suggested that a two-phase concomitant state might be highly dependent on the size and morphologies of the KNN nanostructures. [ABSTRACT FROM AUTHOR]

Published
2020
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148. Evolution is the new deep learning

Author

Miikkulainen, Risto, primary, Hodjat, Babak, additional, Qiu, Xin, additional, Liang, Jason, additional, Meyerson, Elliot, additional, Rawal, Aditya, additional, and Shahrzad, Hormoz, additional

Published
2018
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