RSC Advances

Miao, Hui; Ma, Kelong; Zhu, Huiru; Yin, Kun; Zhang, Ying; Cui, Yumin

doi: 10.1039/c9ra01551epmid: 35516331

The hydrolysis of ammonia borane is a promising strategy for hydrogen energy exploration and exploitation. The in situ produced hydrogen could be directly utilized in hydrogenation reactions. In this work, a bimetallic nickel–cobalt material with porous structure was developed through the pyrolysis of ZIF-67 incorporated with Ni ions. Through the introduction of Ni(NO3)2 as an etching agent, the ZIF-67 polyhedrons were transformed into hollow nanospheres, and further evolved into irregular nanosheets. The bimetallic NiCo phase was formed after pyrolysis in a nitrogen atmosphere at high temperature, with the decomposition and release of organic ligands as gaseous molecules under flowing nitrogen. The obtained bimetallic NiCo porous materials show superior catalytic performance towards hydrolytic dehydrogenation of ammonia borane, thereby nitrobenzene with reducible functional groups can be reduced with high selectivity to the corresponding aniline.

Urushiyama, Hironao; Morito, Haruhiko; Yamane, Hisanori

doi: 10.1039/c9ra01489fpmid: 35516297

Single crystals of (Na/Sr)–(Ga/Si) quaternary type-I clathrates, Na8−ySryGaxSi46−x, were synthesized by evaporating Na from a mixture of Na–Sr–Ga–Si–Sn in a 6 : 0.5 : 1 : 2 : 1 molar ratio at 773 K for 12 h in an Ar atmosphere. Electron-probe microanalysis and single-crystal X-ray diffraction revealed that three crystals from the same product were Na8−ySryGaxSi46−x with x and y values of 7.6, 2.96; 8.4, 3.80; and 9.1, 4.08. It was also shown that increasing the Sr and Ga contents increased the electrical resistivity of the crystal from 0.34 to 1.05 mΩ cm at 300 K.

Ge, Xuan; Sun, Hang; Dong, Kun; Tao, Yanqi; Wang, Qi; Chen, Yazhong; Zhang, Genlei; Cui, Peng; Wang, Ye; Zhang, Qinghong

doi: 10.1039/c9ra01927hpmid: 35516342

Mechanically mixed γ-Al2O3 and HZSM-5 (Si/Al = 50) with different mass ratio were utilized as support for Cu–Co higher alcohol synthesis catalysts prepared through incipient wetness impregnation. The textural and structural properties were studied using Ar low temperature adsorption and desorption, H2-temperature programmed reduction (H2-TPR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and catalytic performance measurements. The results indicated that the mechanically mixed HZSM-5 and γ-Al2O3 supported copper–cobalt catalysts were superior to either γ-Al2O3 or HZSM-5 supported ones with the same metal loading. The results revealed that using HZSM-5 and γ-Al2O3 mechanically mixed benefited the dispersion of metallic phases and stronger synergetic functions between smaller nanoparticles containing copper and/or cobalt, which is essential for HAS from CO hydrogenation. Under working conditions of P = 5.0 MPa, T = 300 °C, V(H2) : V(CO) : V(N2) = 4 : 2 : 1 and GHSV = 7200 mL g−1 h−1, mechanically mixed HZSM-5 and γ-Al2O3 supported catalysts showed higher catalytic activity than those over single support. For CuCo catalysts upon support containing 50.0 wt% HZSM-5 and 50.0 wt% γ-Al2O3, the CO conversion was 21.3% and the C2+ alcohol selectivity was 41.8%.

Luo, Yunying; Xu, Yangyang; Wang, Feng; Li, Chengcai; Wang, Jieqi; Jin, Mengtian; Zhu, Hailin; Guo, Yuhai

doi: 10.1039/c9ra00836epmid: 35516317

Herein, a porous heddle of poly(vinyl butyral) (PVB) was successfully prepared by thermally induced phase separation with PEG400. A phase diagram of PVB was presented, and the effects of various parameters, such as polymer concentration, extrusion temperature, quenching temperature and take-up speed, on the morphology and properties of the PVB porous heddle were investigated. The pore size and porosity of the heddle increase as the extrusion temperature increases. Furthermore, upon increasing the quenching temperature during the TIPS process, the pore size and mechanical properties decrease, whereas porosity increases. In addition, due to the substantially unchanged crystallinity of the PVB heddle, the tensile strength increases since porosity decreases with the increasing take-up speed. The porosity of the prepared PVB porous heddle reached up to 74.63% when the PVB concentration, the quenching temperature and the extrusion temperature were 20 wt%, 0 °C and 170 °C, respectively. Thus, this porous heddle exhibiting a biconnected structure and significant mechanical properties is promising in the field of porous carrier materials.

Wu, Di; Li, Chen; Zhang, Dashuai; Wang, Lili; Zhang, Xiaopeng; Shi, Zaifeng; Lin, Qiang

doi: 10.1039/c9ra02307kpmid: 35516290

Semiconductor photocatalysis is an advanced oxidation process driven by solar energy which has widespread applications in the treatment of organic pollutants in liquid and gas phases. In this work, titanium dioxide nanoparticles modified with yttrium ions (Y3+) were prepared by a ball milling method. The effects of Y3+ mole fraction, ball-to-powder weight ratio, milling time and milling rate on the photocatalytic activities were evaluated by the degradation of methylene blue (MB) under UV light. Then Y3+/TiO2 photocatalysts prepared at the optimized ball milling conditions were applied to treat shrimp wastewater under UV and visible light. Chemical oxygen demand (CODCr), 3D fluorescence spectroscopy and total organic carbon (TOC) were used to detect the water samples taken from the photocatalytic experiments. Experimental results showed that when the mole fraction was 2%, the ball-to-powder weight ratio was 4 : 1, milling time was 4 h and milling rate was 500 rpm, the reaction rate constant of MB degradation can reach up to 0.1112 min−1 which was 4.2 times as fast as pure TiO2. All Y3+/TiO2 samples showed a red shift of absorption compared to pure TiO2 and it led to a visible light absorption response. The content of surface oxygen vacancies has significantly increased and the BET specific area increased to 104 m2 g−1. The CODCr removal rates of shrimp wastewater were 43.8% and 37.5% for 2% Y3+/TiO2 under UV and visible light, respectively. Besides, the TOC removal rates were 67.5% and 38.8%, respectively. Humic-like substances and fulvic-like substances in shrimp wastewater can be mineralized after 90 minutes irradiation.

Oh, Chungik; Kim, Suran; Kim, Hongjun; Park, Gun; Kim, Jaegyu; Ryu, Jeongjae; Li, Panpan; Lee, Sunghwan; No, Kwangsoo; Hong, Seungbum

doi: 10.1039/c9ra01751hpmid: 35516294

In this study, we report the effects of Nafion thickness on the performance of ionic polymer–metal composite (IPMC) actuators. We analyzed the actuation properties of the IPMC actuators, such as displacement and tip force, under external voltage, as a function of their thickness. In order to understand the relationship between thickness and actuation properties, we developed a semi-quantitative model of voltage induced ionic diffusion and its contribution to bending of the Nafion cantilever. Furthermore, we investigated the mechanical properties of the Nafion membranes at sub-micro scale as well as bulk scale, using atomic force microscopy (AFM) and tensile test. The results of the two methods indicated opposite trends of elastic modulus and crystallinity as a function of thickness. We hypothesized that the hot-pressed Nafion was composed of three layers with different crystallinity. Our results suggest that for a high performance IPMC actuator, we need better control of the annealing temperature gradient.

Ye, Mengliang; Jia, Wei; Zhang, Chunhui; Shen, Qingshan; Zhu, Lingyu; Wang, Lisha

doi: 10.1039/c9ra00945kpmid: 35516346

The aim of this study was to isolate and identify osteogenic bioactive peptides from yak bones collagen, while simultaneously investigating their underlying mechanisms for promoting osteoblast proliferation. Response surface methodology (RSM) was employed to investigate the effect of hydrolysis variables on the production of peptides with osteoblast proliferation-promoting activity (OPPA). The concentration of soluble peptides reached 0.5169 mg mL−1, which was well matched with the value (0.5189 mg mL−1) predicted by the model, with the following optimized conditions: hydrolysis time, 3.6 h; pH, 6.12; hydrolysis temperature, 54 °C; E/S (enzyme to substrate) of 5637 U g−1. Hydrolysates were then separated using an ultrafiltration membrane system, and the peptides (<3 kDa) possessed excellent OPPA with a dose–response relationship. A total of 59 novel peptides were identified by HPLC-MS/MS with Mascot analysis. GPSGPAGKDGRIGQPG (GP-16) and GDRGETGPAGPAGPIGPV (GD-18) were selected for docking to investigate the underlying mechanisms of interaction. The molecular docking study revealed that osteoblast proliferation stimulation activity of GP-16 and GD-18 was mainly attributed to the formation of very strong hydrogen bonds with the epidermal growth factor receptor (EGFR). These results indicate that such peptides are promising in the discovery of potential candidates for the future industrial production of functional peptides, which could be used in the mediated treatment of osteoporosis.

Davis, Klinton; Yarbrough, Ryan; Froeschle, Michael; White, Jamel; Rathnayake, Hemali

doi: 10.1039/c9ra02091hpmid: 35516315

A reliable sol–gel approach, which combines the formation of ZnO nanocrystals and a solvent driven, shape-controlled, crystal-growth process to form well-organized ZnO nanostructures at low temperature is presented. The sol of ZnO nanocrystals showed shape-controlled crystal growth with respect to the solvent type, resulting in either nanorods, nanoparticles, or nanoslates. The solvothermal process, along with the solvent polarity facilitate the shape-controlled crystal growth process, augmenting the concept of a selective adhesion of solvents onto crystal facets and controlling the final shape of the nanostructures. The XRD traces and XPS spectra support the concept of selective adhesion of solvents onto crystal facets that leads to yield different ZnO morphologies. The shift in optical absorption maxima from 332 nm in initial precursor solution, to 347 nm for ZnO nanocrystals sol, and finally to 375 nm for ZnO nanorods, evidenced the gradual growth and ripening of nanocrystals to dimensional nanostructures. The engineered optical band gaps of ZnO nanostructures are found to be ranged from 3.10 eV to 3.37 eV with respect to the ZnO nanostructures formed in different solvent systems. The theoretical band gaps computed from the experimental XRD spectral traces lie within the range of the optical band gaps obtained from UV-visible spectra of ZnO nanostructures. The spin-casted thin film of ZnO nanorods prepared in DMF exhibits the electrical conductivity of 1.14 × 10−3 S cm−1, which is nearly one order of magnitude higher than the electrical conductivity of ZnO nanoparticles formed in hydroquinone and ZnO sols. The possibility of engineering the band gap and electrical properties of ZnO at nanoscale utilizing an aqueous-based wet chemical synthesis process presented here is simple, versatile, and environmentally friendly, and thus may applicable for making other types of band-gap engineered metal oxide nanostructures with shape-controlled morphologies and optoelectrical properties.

Zhou, Lang; Li, Zhuo; Zhang, Jinying; Li, Defang; Liu, Dan; Li, Yajie; Wang, Xin

doi: 10.1039/c9ra00559epmid: 35516328

A thin layer porous chromium (Cr) black absorber was fabricated on a polyimide (PI) substrate with 2 inch diameter and 500 nm thickness. The chromium black was prepared by electron beam evaporation and wet-etching process. To optimize the parameters of the absorber, the Cr black was firstly fabricated on silicon and quartz wafers. A high average absorption of 93% over the whole visible spectrum (320 nm to 800 nm) was obtained by 3 min wet-etching of a 400 nm thick metal Cr film. The absorption was higher than 65% when the spectrum extended to near infrared from 800 to 1800 nm. The mechanism of the ultra-broadband absorption can be explained by the light trapping by numerous nanovoids formed inside the Cr film. The nanovoid acts as a blackbody cavity, where the incident light experienced multiple reflections. Using the optimized parameters obtained with silicon and quartz wafers, the Cr black absorber was fabricated on a PI film. Due to its porous structure (low density) and thin thickness, the Cr black/PI composite film showed a strong light absorption and a high optical thermal response. Compared to a PI film without Cr black layer, the average absorption of the composite film was increased from 5.0% to 93.4%, the optical thermal response was improved by 43.5 times. This property highlights its potential applications in various fields such as photo detection and thermal imaging.

Zhang, Yangqian; Xu, Xiangfei; Lu, Jiaorong; Zhang, Shiming

doi: 10.1039/c9ra02022epmid: 35516292

Very recently, organic solar cells (OSCs) have achieved outstanding scientific results with a power conversion efficiency (PCE) of over 16%. However, it is rarely reported on how molecular weight (Mn) of polymer donors affects the solar cell performances. In this work, the wide bandgap polymer donor J51 with different Mn from 8 to 36 kDa were synthesized and used for fabrication of J51:PC71BM devices. It was found that the PCEs were gradually on the increase with the increased molecular weight of J51 donor. This work demonstrated the relationship between devices performance and polymer molecular weight, which enriched the OSCs research content. It provides valuable reference information that optimal molecular weight of polymer donors should be limited in what is considered the applicable range.