RSC Advances

Zhang, Yu

doi: 10.1039/c9ra04419apmid: 35530996

A palladium and boric acid ion co-doped Li3V2(PO4)3/C composite was successfully synthesized by a simple method. A series of characteristics, such as its microstructures and electrochemical properties, were studied. The results show that the modified materials have relatively regular spherical particles and good electrochemical performances for cathode materials. It delivers a high special capacity of 159.2 mA h g−1 at 0.2C and 128.9 mA h g−1 at 5C in the voltage range of 2–4.3 V. After cycling at different rates, the initial discharge capacity retention rate was 97.5%. The enhanced electrochemical properties indicate that the modification method, using anions and cations to collaborative dope the material, effective to improve the electrochemical performance of the electrode material.

Qin, Zhangjie; Chen, Xinmin; Ouyang, Nanqi; Lan, Shuai; Jiang, Guanjie; Zhang, Junxia; Zhang, Qin

doi: 10.1039/c9ra03332gpmid: 35530991

Birnessite is one of the most important manganese oxides that can control the geochemical behaviors of pollutants or can be applied to form industrial products. Many studies have been conducted on the synthesis of hexagonal birnessite because different synthesis methods can affect the structural, morphological, and physicochemical properties of hexagonal birnessite. However, there are still some defects in these synthesis methods. Therefore, a new synthesis method that is rapid, simple, and low-cost was proposed in this study involving the reduction of KMnO4 by H2O2 in a H2SO4 solution without controlling the pH, temperature and pressure. Using a series of XRD, chemical composition, AOS, SSA, SEM, FTIR, and TGA analyses, Bir-H2O2 was found to have lower crystallinity than Bir-HCl. However, the AOS and SSA of Bir-H2O2 were 3.87 and 103 m2 g−1 higher than those of Bir-HCl, i.e., 3.70 and 22 m2 g−1, respectively. Moreover, both Bir-H2O2 and Bir-HCl had similar particle morphology and thermal stability; in addition, the maximum adsorption content of Pb2+ on Bir-H2O2 (∼3006 mmol kg−1) was ∼30% greater than that on Bir-HCl (∼2285 mmol kg−1) at pH 5.5; this indicated that the adsorption of Pb2+ on Bir-H2O2 was better and belonged to a pseudo-second-order model. All the abovementioned results indicate that Bir-H2O2 synthesized herein using the proposed synthesis method can have large application value.

Yaşayan, Gökçen; Orun, Oya; Mega Tiber, Pınar; Rožman, Veronika; Koçyiğit Sevinç, Sevgi

doi: 10.1039/c9ra03783gpmid: 35531028

Understanding cell responses to the topography they are interacting with has a key role in designing surfaces due to the distinctiveness in the responses of different cell types. Thus far, a variety of surface textures have been fabricated, and the cellular responses of diversified cell lines to the surface textures have been assessed together with surface chemistry. However, the results reported in the literature are contradictory, and also not in-depth for inferring the relevance between cells, surface chemistry, and surface topography. Starting from this point of view, we focused on fabricating surfaces having extracellular matrix-like surface patterns and investigated the influence of patterning on human ovarian cancer cells. In this study, hemispherical protrusion-shaped, nanotextured surfaces were prepared via colloidal lithography and polymer casting methods using monolayer templates prepared from 280 nm, 210 nm, and 99 nm polystyrene particles and polydimethylsiloxane moulds. Then, the surface textures were transferred to biocompatible polycaprolactone films. After the characterisation of the surfaces via atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle measurements, the cellular response to topography was evaluated by cell attachment, viability, and apoptosis studies. The results were compared with non-textured surfaces and control plate wells. The results showed that human ovarian cancer cell attachment increased with nanotexturing, which suggests that nanotexturing may be a promising approach for cancer cell modulation, and may have the potential to introduce new strategies for cancer treatment.

Wu, Lihang; Xie, Qinglong; Lv, Yongbo; Zhang, Zhiyong; Wu, Zhenyu; Liang, Xiaojiang; Lu, Meizhen; Nie, Yong

doi: 10.1039/c9ra05238kpmid: 35530987

The degradation of methylene blue (MB) using a novel dielectric barrier discharge plasma reactor coupled with activated carbon supported polyurethane foam (AC/PUF) was investigated in this paper. The plasma reactor combining a glass bead-packed bed and a microporous plate was developed. The AC/PUF provided sufficient contact area between carbon media and pollutants and hence revealed a good MB removal capacity. The effects of input voltage and initial MB solution concentration on MB degradation efficiency were examined. Kinetic study indicated that plasma and AC/PUF in the coupled system had a good synergistic effect in MB degradation. The degradation efficiency of 100 ppm MB solution could reach 97.9% with 10 min treatment in the coupled system, which was close to that obtained by plasma treatment alone for 30 min (97.5%). The COD removal in the plasma and AC/PUF coupled system (90.7%) was much higher than that obtained by plasma treatment followed by AC/PUF adsorption (58.3%). In addition, the energy yield (G50) of the coupled system was up to 38.3 g kW−1 h−1, suggesting great energy efficiency of the system. Moreover, repeated use experiments of AC/PUF showed the good utilization potential of the coupled system. Finally, a possible degradation pathway of MB was proposed.

Song, Quanwei; Chen, Changzhao; Yu, Wenhe; Yang, Lixia; Zhang, Kunfeng; Zheng, Jin; Du, Xianyuan; Chen, Hongkun

doi: 10.1039/c9ra04476kpmid: 35531001

Herein, we develop a facile method for selective and sensitive detection of hydroxylamine (HA) based on the in situ formation of DNA templated copper nanoparticles (DNA-CuNPs) as fluorescent probes. It is firstly found that HA as a reducing agent can play a key role in the in situ formation of fluorescent DNA-CuNPs. This special optical property of DNA-CuNPs with (λex = 340 nm, λem = 588 nm) with a mega-Stokes shifting (248 nm) makes it applicable for the turn-on detection of HA. In addition, this fluorescent method has several advantages such as being simple, rapid, and environmentally friendly, because it avoids the traditional organic dye molecules and complex procedures. Under optimized conditions, this platform achieves a fluorescent response for HA with a detection limit of 0.022 mM. Especially, successful detection capability in tap waters and ground waters exhibits its potential to be general method.

Torbina, Viktoriia; Salaev, Mikhail; Vodyankina, Olga

doi: 10.1039/c9ra05003epmid: 35531019

The effect of solvent nature on conversion, product yields and reaction kinetics of selective propylene glycol oxidation with tert-butyl hydroperoxide over porous chromium terephthalate Cr-MIL-101 used as a heterogeneous catalyst is considered. Differences in hydrogen bonding of propylene glycol molecules in different solvents and adsorption of components of the reaction mixture on the active sites of the catalyst are studied by Fourier-transformed infrared spectroscopy. The characteristics of the solvent are shown to play a key role in the process under consideration. In the case of aprotic solvents, the oxidant utilization efficiency, the propylene glycol conversion and the product yields are significantly higher in comparison with those in protic solvents. The protic solvents can adsorb on the active sites of the catalyst which leads to a decrease of their accessibility for the reagents. The initial rate of propylene glycol oxidation decreases linearly with the increasing of the diameter of molecules of the protic solvents. DFT calculations support the competitive adsorption of the molecules of protic solvents on Cr active sites of MIL-101. In the aprotic solvents, the reactivity and distribution of propylene glycol molecules in the solution are determined by the involvement of hydroxyl groups of the substrate into the intermolecular interactions. The ability of the aprotic solvents to break the hydrogen bond network in the associates of propylene glycol is responsible for the concentration of the substrate molecules in the pores of Cr-MIL-101. The highest selectivities towards hydroxyacetone for Cr-MIL-101 catalyst are obtained in solvents, where the initial rates of propylene glycol oxidation are the lowest ones.

Yamamoto, K.; Wang, X.-X.; Tamaki, M.; Suzuki, K.

doi: 10.1039/c9ra00755epmid: 35531029

Following the first attempt at producing gas from a naturally occurring methane hydrate (MH) deposit in the Daini–Atsumi Knoll in the eastern Nankai Trough area off Honshu Island, Japan in 2013, a second attempt was made in April to June of 2017 at a nearby location using two producer wells sequentially and applying the depressurization method. The operation in the first borehole (AT1-P3) continued for 12 days with a stable drawdown of around 7.5 MPa and 41 000 m3 of methane gas being produced despite intermittent sand-production events. The operation of the other borehole (AT1-P2) followed, with a total of 24 days of flow and 222 500 m3 of methane gas being produced without sand problems. However, the degree of drawdown was limited to 5 MPa because of a higher water production rate than expected in the second hole. The pressure and temperature sensors deployed in the two producers, along with the two monitoring holes drilled nearby, gathered reservoir response data and information about the long-term MH dissociation processes in the vicinity of the production holes in the temporal and spatial domains. Although the ratio of energy return to the input was considerably larger than that for the depressurization operation, some observations (e.g., the high contrast in the production rates between the two holes and the almost constant or slightly reduced gas production rates) were not predicted by the numerical models. This failure in prediction raises questions about the veracity of the reservoir characteristics modeled in the numerical simulations. This paper presents the operation summaries and data obtained with thought-experiment based-anticipated production behaviors and preliminary analysis of the obtained data as the comparison with expected behaviors. Detailed observations of gas and water production, as well as the pressure and temperature data recorded during the gas flow tests, indicate that the heterogeneous MH distribution within the reservoir was mainly responsible for the discrepancies observed between the anticipated and actual behaviors. Furthermore, the motion of the water that does not originate from MH dissociation introduces complexity, such as the occurrence of concentrated water-producing intervals and unexpected gas production responses to decreases in pressure, into the production behavior. The influence of heterogeneity should be clearly understood for the accurate prediction of gas production behavior based on MH reservoirs.

Sapozhnikova, Ksenia A.; Slesarchuk, Nikita A.; Orlov, Alexey A.; Khvatov, Evgeny V.; Radchenko, Eugene V.; Chistov, Alexey A.; Ustinov, Alexey V.; Palyulin, Vladimir A.; Kozlovskaya, Liubov I.; Osolodkin, Dmitry I.; Korshun, Vladimir A.; Brylev, Vladimir A.

doi: 10.1039/c9ra06313gpmid: 35531032

The propargylamide of N3-Pom-protected 5-(perylen-3-ylethynyl)uracil acetic acid, a universal precursor, was used in a CuAAC click reaction for the synthesis of several derivatives, including three ramified molecules with high activities against tick-borne encephalitis virus (TBEV). Pentaerythritol-based polyazides were used for the assembly of molecules containing 2⋯4 antiviral 5-(perylen-3-ylethynyl)uracil scaffolds, the first examples of polyvalent perylene antivirals. Cluster compounds showed enhanced absorbance, however, their fluorescence was reduced due to self-quenching. Due to the solubility issues, Pom group removal succeeded only for compounds with one peryleneethynyluracil unit. Four compounds, including one ramified cluster 9f, showed remarkable 1⋯3 nM EC50 values against TBEV in cell culture.

Deng, Zhongxun; Wang, Xianhui

doi: 10.1039/c9ra03175hpmid: 35531004

Combining two different layered structures to form a van der Waals (vdW) heterostructure has recently emerged as an intriguing way of designing electronic and optoelectronic devices. Effects of the strain on the electronic properties of GaN/graphene heterostructure are investigated by using first-principles calculation. In the GaN/graphene heterostructure, the strain can control not only the Schottky barrier, but also contact types at the interface. Moreover, when the uniaxial strain is above −1% or the biaxial strain is above 0%, the contact type transforms to ohmic contact. These results provide a detailed understanding of the interfacial properties of GaN/graphene and help to predict the performance of the GaN/graphene heterostructure on nanoelectronics and nanocomposites.

Wang, Zanhao; Wu, Honglin; Liu, Xiaosong; Song, Yunfei; Yang, Yanqiang

doi: 10.1039/c9ra04645cpmid: 35531038

A coupled oscillator model with special attention to the electron is employed to simulate the time- and frequency-resolved coherent anti-Stokes Raman scattering (TFR-CARS) spectrum of benzene, where the electronic contribution is introduced as an oscillator as well as molecular vibration, and both the coupling between molecular vibrations and the coupling between electron and molecular vibration are involved. Through the simulation, the intramolecular vibrational energy redistribution (IVR) process is confirmed to occur more readily between the molecular vibrations with the same vibrational symmetry. Moreover, it is found that the electron plays a mediator role in the IVR process, and the coupling between electron and molecular vibration significantly increases the intramolecular vibrational energy transfer efficiency.