An attractive approach for the production of transportation fuels from renewable biomass resources is to convert oxygenates into alkanes. In this paper, C5–C20 alkanes formed via the hydrogenation ...and hydrodeoxygenation of the oligomers of furfuryl alcohol(FA) can be used as gasoline, diesel and jet fuel fraction. The first step of the process is the oligomers of FA convert into hydrogenated products over Raney Ni catalyst in a batch reactor. The second step of the process converts hydrogenated products to alkanes via hydrodeoxygenation over different bi-functional catalysts include hydrogenation and acidic deoxidization active sites. After this process, the oxygen content decreased from 22.1 wt% in the oligomers of FA to 0.58 wt% in the hydrodeoxygenation products.
Two-dimensional Ti3C2T x MXene-based hybrids-anchored magnetic metal nanoparticles show a huge potential application as effective wave absorbers due to the synergistic electromagnetic (EM) loss ...effect. In this work, uniform and size-controllable nickel, cobalt, or nickel–cobalt alloy nanoparticles were in situ grown on the surface of MXene via a facile and moderate co-solvothermal method for the first time. As an example, a nickel nanoparticles-anchored MXene (Ni@MXene) hybrid was homodispersed into dielectric polyvinylidene fluoride to develop its EM wave-absorbing capacity to a great extent. As expected, the results showed strong reflection loss (RLmin = −52.6 dB at 8.4 GHz), broad effective absorption bandwidth (EAB = 3.7 GHz including 71% of X-band), low loading (10 wt % Ni@MXene), and thin thickness (3.0 mm). By adjusting the sample thickness, EAB can cover completely the whole X-band with a maximum of 6.1 GHz, showing a huge potential of Ni@MXene hybrid applying as aircraft stealth coating. The mechanism analyses revealed that the excellent impedance matching, magnetocoupling effect, conductance, magnetic loss, and multiple scatterings contribute to the splendid EM wave-absorbing performance of the Ni@MXene hybrid. Considering the excellent overall performance, the Ni@MXene hybrid was identified as a promising candidate for EM wave absorption.
The engineered interfaces of complex oxides have abundant physical properties and provide a powerful platform for the exploration of fundamental physics and emergent phenomena. In particular, ...research on the two-dimensional magnetic systems with high mobility remains a long-standing challenge for the discovery of quantum phase and spintronic applications. Here, we introduce a few atomic layers of the delta doping layer at LaAlO3/SrTiO3 interfaces through elaborately controllable epitaxial growth of SrRuO3. After inserting a SrRuO3 buffer layer, the interfaces exhibit a well-defined anomalous Hall effect up to 100 K and their mobility is enhanced by 3 orders of magnitude at low temperatures. More intriguingly, a large unsaturated positive magnetoresistance is created at interfaces. Combining with the density functional theory calculation, we attribute our findings to the electron transfer at interfaces and the magnetic moment of Ru4+ 4d bands. The results pave a way for further research of two-dimensional ferromagnetism and quantum transport in all-oxide systems.
•The spin coating also can epitaxially grow LaAlO3 film consistent with (001) orientation of STO substrate.•All of the LAO/STO heterointerfaces exhibit a perfect metallic conductive behavior under ...the similar thickness.•The chemical method of spin coating can effectively avoid the ablation of high-energy plume.•The two dimensional electron gas prepared by the spin coating exhibits a smaller sheet resistance and higher mobility.
The two dimensional electron gas (2DEG) exhibits a considerable potential in all-oxide electronics due to the emergence of novel physical phenomena at the typical LaAlO3/SrTiO3 (LAO/STO) heterointerfaces. However, the quality and property of 2DEG are distinctly influenced by the preparation method. Herein, we compare the pulsed laser deposition (PLD) and spin coating method by obtaining high-quality 2DEGs. The comparative studies show that all the LAO/STO heterointerfaces exhibit a perfect metallic conductive behavior under the similar thickness. Moreover, the results by SC exhibit smaller sheet resistance and higher mobility, which is attributed to fewer defect states at heterointerfaces because the chemical method can effectively avoid the ablation of high-energy plume in PLD process. Therefore, our works provide a promising fabrication method for oxide heterointerfaces with a convenient, gentle, large scale and low cost, expanding the way for the application of all-oxide electronic devices.
Application of multifunctional integrated devices represents a main trend in the future. However, it is still a great challenge to realize ferroelectric metals in a single system. Here, we report the ...coexistence of metallicity and ferroelectricity-like polarization at GdAlO3/SrTiO3 heterointerfaces. The results show that the asymmetric bistable polarization in the GdAlO3 film is attributed to the spontaneous polarization of oxygen vacancies. Furthermore, the transport property of GdAlO3/SrTiO3 heterointerfaces can be significantly manipulated by switching the polarization state. It is observed that the switchable conductance significantly improves under the influence of a polarization state at 6 V. Its change in the resistance is about 17.2% under 10 V, which accelerates the commercial application of oxide devices.
Complex oxide heterointerfaces provide a platform to manipulate spin–orbit coupling under the broken inversion symmetry. Moreover, their weak antilocalization (WAL) effect displays quantum coherent ...behavior due to the strong spin–orbit coupling. Herein, we break through the limitation of lattice mismatch at ReAlO3/STO (Re = La, Pr, Nd, Sm, and Gd) heterointerfaces and obtain their two-dimensional electric gas (2DEG) by spin coating. The effect of different Re elements in the resulting quantum corrections on the conductivity is investigated. It is observed that the conductivity of heterointerfaces is reduced with larger atomic numbers due to the ionization potential of Re elements. Moreover, magnetoresistance (MR) measurements in a perpendicular or a parallel field distinctly uncover strong Rashba spin–orbit coupling (SOC) in ReAO/STO samples besides SAO/STO (Re = Sm) and GAO/STO (Re = Gd), and the effective fields of the SOC (H so) gradually increase from LAO/STO (Re = La, H so = 0.82 T) to NAO/STO (Re = Nd, H so = 1.37 T) at 2 K. The competition between SOC scattering and inelastic scattering is revealed through a temperature-dependence study of MR, and the WAL–weak localization transition is at about 6 K. Furthermore, unambiguous results of the Kondo effect, nonlinear Hall, hysteresis loop, and Rashba SOC suggest the coexistence of WAL at the PAO/STO (Re = Pr) heterointerface with exchange coupling between the localized magnetic moment and the itinerant electron. These results pave a unique route for the exploration of spin-polarized 2DEGs at oxide heterointerfaces.
Although the amorphous two-dimensional electron gas (a-2DEG) of oxides provides new opportunities to explore nanoelectronic as well as quantum devices, the intrinsic effect of rare earth (Re = La, ...Pr, Nd, Sm, Gd, and Tm) elements at ReAlO3/SrTiO3 heterointerfaces is still largely unknown and needs to be addressed systematically. Herein, we first propose that the ionization potential of Re elements is a critical factor for the 2DEG fabricated by chemical spin coating. Furthermore, the photoresponsive properties of heterointerfaces are investigated comprehensively with the ionization potential ranging from 35.79 to 41.69 eV. The results show that the sheet resistances significantly increase with increasing the ionization potential, and a resistance upturn phenomenon is observed at TmAlO3/SrTiO3 heterointerfaces, which can be attributed to the weak localization effect theoretically. The most important observation is the dramatic transition from negative (−178.3%, Re = La) to positive (+89.9%, Re = Gd) photoresponse at ReAlO3/SrTiO3 heterointerfaces under the irradiation of 405 nm light at 50 K. More remarkably, a unique recovery behavior of transient–persistent photoconductivity coexistence at low temperatures is discovered at the TmAlO3/SrTiO3 heterointerface. This work reveals an effective approach to tune the transport and photoresponsive properties by changing Re elements and paves the way for the application of all-oxide devices.
C9-C25 oxygen-containing compounds formed via the condensation reaction of furfuryl alcohol(FA) can be used as fuel intermediates for the production of bio-fuel. In this paper, the condensation ...reaction of FA was carried on over sulfuric acid catalyst in a batch aqueous phase reactor, in which the produced oligomers were separated from aqueous reaction system automatically before they went on further to form polymers. Reaction kinetics experiments showed that the values of reaction order of FA and sulfuric acid all were 1. The molecular structure and content of short chain-length oligomers B (C9-C25) were analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography (GC) respectively. The molecular weight of FA condensate was determined by gel permeation chromatography (GPC). According to the information provided by GC/MS and GPC, we revealed that two polymerization mechanisms, step-growth polymerization and chain-growth polymerization, coexist in FA condensation reaction process in aqueous system. A simplified kinetics model based on the present mechanisms was established, and condensation products were divided into short chain-length oligomers B (C9-C25) and long chain-length oligomers C (>C25).
•C9-C25 oligomers are produced in a batch aqueous phase reactor.•Oligomers can be hydrogenated to produce biodiesel.•Oligomers are separated automatically before they further form polymers.•Two polymerization mechanisms coexist in FA condensation reaction process.•A simplified kinetics model in quasi-homogeneous water system is developed.
PDF
