ABSTRACT Tailoring polymeric carbon nitride (CN) to simultaneously broaden its light absorption range and improve charge carrier mobility remains a key challenge for photocatalytic H 2 O 2 production. The molecular junction strategy has been proven to be an effective approach to address the aforementioned challenges. In this work, we developed a molecular junction through controlled thermal ring‐opening isomerization of benzoguanamine, thereby creating a well‐defined C‐C‐bridged benzene‐heptazine molecular junction. Experimental and theoretical studies reveal that: (1) Benzene functionalization extends the π‐conjugation, enabling n→π* transitions for broad‐spectrum absorption; (2) The donor‐acceptor structure enhances self‐polarization effects, strengthening the built‐in electric field for efficient charge separation; (3) The unique molecular architecture overcomes traditional kinetic limitations, enabling a dual‐channel H 2 O 2 synthesis mechanism. The optimized catalyst achieves remarkable production rates of 5222 µmol∙g − 1 ∙h − 1 in isopropanol/water and 1587 µmol∙g −1 ∙h −1 in pure water, representing 13.1‐fold and 32.4‐fold improvements over pristine CN, respectively. This work advances molecular‐scale design of photocatalysts and offers new strategies for artificial photosynthesis.

The robust Mg-H bonds present in magnesium hydride (MgH2) hinder the dissociation of hydrogen molecules on MgH2, leading to suboptimal thermo dynamic and kinetic properties. Transition metals such as nickel (Ni) and Nb exhibit superior hydrogen absorption energies as compared to Mg. By integrating two-dimensional NbnCn-1Tx-MXene (with a large specific surface area and strong hydrogen absorption capacity provided by Nb) with Ni clusters, we developed an effective catalyst for hydrogen adsorption in MgH2. This study focused on the synthesis of an efficient MXene-Nb2CTx composite containing nano Ni cluster to enhance the hydrogenation and dehydrogenation processes of the Mg/MgH2 system. The Tx end groups (–F, –O) were found to interact with Ni to create Ni-F or Ni–O bonds, which subsequently engage with adjacent Ni atoms to form Ni–Ni bonds. This interaction facilitates the loading of Ni clusters onto Nb2CTx and mitigates the inhibitory effects of –F or –O on hydrogen adsorption and desorption in the Mg-based system. Consequently, Nb2C and Ni operate synergistically to enhance hydrogen dissociation and weaken Mg-H bonds. Theoretical simulations revealed that the inclusion of the Nb2C/Ni catalyst in an elongation of Mg-H bonds enhance hydrogen dissociation and weaken Mg-H bonds. Theoretical simulations revealed that the inclusion of the Nb2C/Ni catalyst in an elongation of Mg-H bonds facilitate hydrogen molecule dissociation on the Nb2C/Ni composite. Hydrogen storage performance assesments demonstrated that the Nb2C/Ni catalyst efficiently catalyzed hydrogen absorption and desorption; specifically, the hydrogenation/dehydrogenation capacity of Nb2C/Ni@MgH2 reachedca. 5.0 wt

The robust Mg‐H bonds present in magnesium hydride (MgH 2 ) hinder the dissociation of hydrogen molecules on MgH 2 , leading to suboptimal thermo dynamic and kinetic properties. Transition metals such as nickel (Ni) and Nb exhibit superior hydrogen absorption energies as compared to Mg. By integrating two‐dimensional Nb n C n‐ 1 T x ‐MXene (with a large specific surface area and strong hydrogen absorption capacity provided by Nb) with Ni clusters, we developed an effective catalyst for hydrogen adsorption in MgH 2 . This study focused on the synthesis of an efficient MXene‐Nb 2 CT x composite containing nano Ni cluster to enhance the hydrogenation and dehydrogenation processes of the Mg/MgH 2 system. The T x end groups (–F, –O) were found to interact with Ni to create Ni‐F or Ni–O bonds, which subsequently engage with adjacent Ni atoms to form Ni–Ni bonds. This interaction facilitates the loading of Ni clusters onto Nb 2 CT x and mitigates the inhibitory effects of –F or –O on hydrogen adsorption and desorption in the Mg‐based system. Consequently, Nb 2 C and Ni operate synergistically to enhance hydrogen dissociation and weaken Mg‐H bonds. Theoretical simulations revealed that the inclusion of the Nb 2 C/Ni catalyst in an elongation of Mg‐H bonds enhance hydrogen dissociation and weaken Mg‐H bonds. Theoretical simulations revealed that the inclusion of the Nb 2 C/Ni catalyst in an elongation of Mg‐H bonds facilitate hydrogen molecule dissociation on the Nb 2 C/Ni composite. Hydrogen storage performance assesments demonstrated that the Nb 2 C/Ni catalyst efficiently catalyzed hydrogen absorption and desorption; specifically, the hydrogenation/dehydrogenation capacity of Nb 2 C/Ni@MgH 2 reachedca. 5.0 wt% at 100 °C, while at 200 °C, the capacities for hydrogenation and dehydrogenation reached 7.0 wt% and 6.0 wt%, respectively, within 6 min.

The nickel atoms were introduced into the porous h-BN matrix through Ni–B bonds; this Ni/Ni x B@MgH 2 exhibits an capacity of about 7.0 wt% at 200 °C, releasing H 2 of approximately 4.5 wt% H 2 within 10 min, with stable reversible cycling.

CdTiO3/Ti3C2 MXene (CdTiO3/TCM) heterojunctions were created using coordination-solvothermal synthesis, effectively addressing the rapid recombination and slow migration of photogenerated carriers in single semiconductor photocatalysts. The CdTiO3/TCM heterojunction consists of shuttle-like CdTiO3 structures implanted on the surface of multilayered Ti3C2 MXene, significantly enhancing the specific surface area and visible light capture capability. The photocatalytic degradation rate constant of CdTiO3/TCM-B under visible light for Rhodamine B (RhB) reached 8.7 x10-3 min-1, 7.25 times that of pure CdTiO3. CdTiO3/TCM-B maintained high degradation activity even after five cycles of use. Experimental results indicate that superoxide radicals (center dot O2-) and hydroxyl radicals (center dot OH) were the main active species in the degradation process of RhB. Analysis of photoelectric properties and band structure revealed the role of the heterojunction structure in promoting the separation and transfer of photogenerated charges. The results confirm that Ti3C2 MXene, as a cocatalyst for CdTiO3, can significantly improve photocatalytic performance, demonstrating the potential for developing new visible light photocatalysts.

The active sites in porous carbon nanotube (CNT) would determine hydrogen storage performance of CNT. Here, we reported an effective, simple and controllable strategy to improve the hydrogen storage property of function group grafted CNT (fg-CNT). N-CNT-M (La2O3, Ni) would be obtained by the mixture of fg-N-CNT and metallic precursor at calcination of 600 degrees C. N-CNT-La2O3 has the highest H2 storage capacity of 7.4 wt%, displaying stable hydrogen adsorption/ desorption cycles for more than 20 times at 100 degrees C and 18 bar. fg-Ni-CNT-PLLA were formed by electrostatic interactions between C-N bond of amide and carbonyl of L-polylactic acid (PLLA). fg- Ni-CNT-PLLA also has H2 storage capacity of 6.2 wt% at 100 degrees C and 18 bar. The experiment found that metal ions or PLLA might be dispersed uniformly in CNT by adjusting the ratio of grafted hydroxyl (OH) to acylamino (-CONH2). N-CNT-La2O3 has better hydrogen storage performance than fg-CNT-PLLA because the aggregation of CNT would be caused by the molecular movement of PLLA during hydrogenation and dehydrogenation. This work provides guidance for the development of efficient hydrogen storage materials.

Amorphous catalysts have a large number of catalytic active sites. Here, we report a magnesium composite trace lanthanum catalyst (La@Mg), in which La and Mg layers form amorphous MgeLa compound on the surface of layered Mg. The test shows this La@Mg has hydrogen storage capacity of about 7.6 wt% and hydrogen desorption of 7.2 wt%, higher than that of crystalline La@Mg and sole Mg, rapid absorption/desorption kinetic and stable reversible absorption/desorption cycles. La@Mg exhibits an optimistic hydrogen storage performance than Mg-based materials previously reported in the literature. Combined with theoretical calculations, it is shown that the amorphous MgeLa has an catalysis on hydrogen storage performance of La@Mg system, which contributing to the dispersion of Mg and providing channels for hydrogen diffusion, facilitating hydrogenation by accelerating H atoms diffuse between the subsurface and the surface. This work provides experiment and mechanism guidance for the development of efficient hydrogen storage materials. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Memristors will be critical components in the next generation of digital technology and artificial synapses. Researchers are investigating innovative mechanistic understanding of the memristor devices based on low-cost, solution-processable, and organic materials as promising candidates. Here, we demonstrate a novel polyelectrolyte-based memristor device, which is simply prepared by spin-coating poly(acrylic acid) (PAA) and polyethylenimine (PEI) on an indium tin oxide (ITO) substrate followed by a magnetron sputtering of the ITO as the top electrode. The device has a potential to achieve excellent resistive switching (RS) performance and synapse functionality as well as greater flexibility and transmittance when compared to the oxide-based memories. An on/off resistance ratio of 50 can be maintained without degradation for up to 20 000 cycles (flat state) and over 4000 cycles (bending to a 2 mm radius 10 000 times) in the DC sweep mode. Moreover, the device performs various synaptic functions, including spike-timing-dependent plasticity, pulse pair plasticity, and short-term and long-term plasticity in the potentiation and depression processes. The counterions and two oppositely charged polyelectrolyte chains can move in and out of each other depending on the applied electrical potential (pulse), resulting in a change in the potential drop at the interface of the polyelectrolyte bilayer and its electrodes, which can be attributed to the RS mechanism and various synaptic functions. This insight may accelerate the technological deployment of the organic resistive memories.

Atomic doping or polymer grafting can significantly improve the hydrogen sorption performance of hexagonal boron nitride (h-BN) based materials. Herein, this paper reported h-BN nanosheets grafting degradable L-polylactic acid (PLLA) and h-BN nanosheets doping nickel nanoparticles (Ni NPs) for high efficiency hydrogen storage. Firstly, h-BN material was treated by sodium hydroxide solution, which the electronegativity B atom connected with -OH covalently and h-BN nanosheets would disperse uniformly. Then, Ni-h-BN powder would be achieved by calcining the mixture of Ni precursor and h-BN at 600 degrees C. PLLA-h-BN film would be achieved by PLLA composite alkali modified h-BN, so that the long molecular chains of PLLA were grafted to h-BN nanosheets. The experiment found h-BN nanosheets dope trace Ni and h-BN nanosheets graft PLLA would improve H-2 sorption ability of h-BN by adjusting electron structure and expanding interlayer space of h-BN, simultaneously. The test indicted Ni-h-BN has H-2 storage capacity of 7.3 wt%, PLLA-h-BN has H-2 storage capacity of 6.1 wt% at room temperature and 15 bar, these h-BN materials exhibited an optimistic hydrogen storage performance than h-BN materials previously reported in literature. This work has provided effective strategy for the development of efficient hydrogen storage materials.

Doping engineering is an effective strategy to improve the hydrogen storage capacity of magnesium-based materials. Here, we report a magnesium composite containing trace amounts of nickel catalyst (Ni-Mg), in which Ni and Mg layers form a new structural phase. The test shows that Ni-Mg composite has a hydrogen storage capacity of 7.5 wt%, with rapid absorption/desorption kinetics and stable reversible absorption/desorption performance on cycling. Ni-Mg exhibits a superior hydrogen storage performance as compared to the MgNi alloys and Mg-based materials previously reported in the literature. We conclude that a new MgNi phase and MgNi2 intermetallic compound are formed during the H-2 adsorption process. Based on the theoretical calculations, we show that Ni facilitates hydrogenation by accelerating the dissociation of H-2 molecules into the H atoms, while the MgNi phase formed during the hydrogenation is conducive to the subsequent dehydrogenation, promoting H atoms diffusion between the subsurface and the surface. This work provides a guidance for the development of the efficient hydrogen storage materials. (C) 2022 Elsevier B.V. All rights reserved.

In the context of protecting Mg-based nano-objects for potential hydrogen storage applications, the potential of C:H layer as a barrier polymer material deposited by the plasma-enhanced chemical vapor deposition process is examined. Corrosion tests reveal (a) good barrier properties of the C:H layer and (b) suggest an increase in the internal stress with the power dissipated in the plasma. The latter is attributed to an increase in the cross-linking density of the coatings accompanied by an increase in the stiffness as shown by nanoindentation measurements. Finally, for a given set of plasma parameters, Mg-based nanowires were successfully enrobed by the C:H coatings as evidenced by scanning electron microscopy measurements.

The nano metallic-based material has received the particular attention of scientists in H-2 storage. Herein, an efficient air-stable nano metallic magnesium (Mg)-Polymethyl methacrylate (PMMA) system, in which methyl magnesium chloride (MeMgC1) as organic Mg precursor is in-situ reduced to metallic Mg particles (Mg NPs) by lithium naphthalene (Li-naphthalene) in soluble PMMA/THF system, exhibits an excellent H-2 storage performance and do not require harsh operation condition. In order to form well-distributed Mg NPs (co. 5 nm) in PMMA gel framework, it is an important procedure to mix Mg ion and Li-naphthalene completely, as well the restriction effect of polymer molecular chain. The synthesized mechanism of nanocomposite and the optimal reaction conditions were ascertained by designing a series of experiments. Notably, PMMA can not confined the size of metallic Mg by blending method, and the mixed beta/gamma-Mg presents nearly no ability to adsorb hydrogen. Here, the air stable Mg NPs is in-situ reduced in PMMA can be reacted with H-2, and O-2 and H2O molecules can not be infiltrated into PMMA. The correlation between the size of Mg NPs, the amount of PMMA and hydrogen storage performance for the PMMA-Mg NPs composite (PMC) is studied. We have found that hydrogen storage capacity of PMC could be enhanced as decreasing the size of Mg NPs by adjusting the amount of PMMA. The Mg NPs in PMMA might release the higher amount of H-2 at below 300 degrees C with a rapid absorption/desorption kinetics than the reported material in literature. The obtained nanocomposite are able to deliver dense hydrogen in demanding environments. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Biodegradable devices for medical applications should be with an appropriate degradation rate for satisfying the various requirements of bone healing. In this study, composite materials of polylactic acid (PLA)/stearic acid-modified magnesium oxide (MgO) with a 1 wt% were prepared through blending extrusion, and the effects of the MgO shapes on the composites' properties in in vitro and in vivo degradation were investigated. The results showed that the long-term degradation behaviors of the composite samples depended significantly on the filler shape. The degradation of the composites is accelerated by the increase in the water uptake rate of the PLA matrix and the composite containing the MgO nanoparticles was influenced more severely by the enhanced hydrophilicity. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO through the neutralization of the acidic product of the PLA degradation. In addition, the improvement of the in vivo degrading process of the composite illustrated that the PLA/MgO materials can effectively regulate the degradation of the PLA matrix as well as raise its bioactivity, indicating the composites for utilization as a biomedical material matching the different requirements for bone-related repair.

Today, Mg is foreseen as one of the most promising materials for hydrogen storage when prepared as nano-objects. In this context, we have studied the fabrication of Mg nano-sculpted thin films by magnetron sputtering deposition in glancing angle configuration. It is demonstrated that the microstructure of the material is controllable by tuning important deposition parameters such as the tilt angle or the deposition pressure which both strongly affect the shadowing effect during deposition. As an example, the angle formed by the column and the substrate and the intercolumnar space varies between ~20° to ~50° and ~45 to ~120 nm, respectively, when increasing the tilt angle from 60° to 90°. These observations are highlighted by modeling the growth of the material using kinetic Monte Carlo methods which highlights the role of surface diffusion during the synthesis of the coating. This work is a first step towards the development of an air-stable material for hydrogen storage.

The present work focuses on the preparation of poly(l-lactide)-magnesium oxide whiskers (PLLA-MgO) composites by the in-situ polymerization method for bone repair and implant. PLLA-MgO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and solid-state 13C and 1H nuclear magnetic resonance spectroscopy (NMR). It was found that the whiskers were uniformly dispersed in the PLLA matrix through the interfacial interaction bonding between PLLA and MgO; thereby, the MgO whisker was found to be well-distributed in the PLLA matrix, and biocomposites with excellent interface bonding were produced. Notably, the MgO whisker has an effect on the crystallization behavior and mechanical properties; moreover, the in vivo degradation of PLLA-MgO composites could also be adjusted by MgO. These results show that the whisker content of 0.5 wt % and 1.0 wt % exhibited a prominent nucleation effect for the PLLA matrix, and specifically 1.0 wt % MgO was found to benefit the enhanced mechanical properties greatly. In addition, the improvement of the degrading process of the composite illustrated that the MgO whisker can effectively regulate the degradation of the PLLA matrix as well as raise its bioactivity. Hence, these results demonstrated the promising application of PLLA-MgO composite to serve as a biomedical material for bone-related repair.

High-energy density and low cost magnesium nanoparticles (Mg NPs)-based material are being sought to meet increasing capable of hydrogen (H-2) storage demand. Here, a kind of air-stable Mg NPs supported on porous structured multi-walled carbon tubes-polymethyl methacrylate (MWCNTs-PMMA) template is prepared owing to reversible well distributed, dispersed and small-sized Mg/MgH2 NPs. The aim is to improve the H-2 storage capacity, hydrogen sorption kinetics and thermodynamics of nano Mg -based system without using catalyst. The organic Mg precursor was directly in-situ reduced to metallic Mg NPs in MWCNTs-PMMA template by lithium naphthalide. The size distribution of reduced Mg nanoparticles is around 3.6 +/- 0.2 nm, confirmed by XRD and TEM analyses, which is due to the strong interaction between Mg NPs and MWCNTs-PMMA via PMMA binding Mg2+, as well as the confinement of porous template hindered the growth and agglomeration of Mg NPs. Moreover, except H-2, O-2 and H2O molecules can't infiltrate the porous structure of MWCNTs-PMMA resulted in the presence of air stable Mg NPs in the MWCNTs-PMMA. The work provides a new scope to prepare nano metal-based composite for H-2 storage. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

建立了纸张中的20种芳香胺的分散固相萃取/气相色谱-三重四极杆串联质谱分析方法.纸张中的偶氮染料于(70±2)℃经预处理后还原为芳香胺,向反应后的悬浮液中先加入4 mL 10 mol/L氢氧化钠溶液,将pH值由弱酸性调至碱性,再加入0.5 mL的3内标(氘代萘、2,4,5-三氯苯胺和氘代蒽)工作溶液、10 mL的叔丁基甲醚,最后加入15 g无水硫酸钠除水,振摇40 min萃取芳香胺.萃取液经分散固相萃取试剂盒(d-SPE)进一步净化、离心后,取上层清液以气相色谱-三重四极杆串联质谱法(GC-MS/MS),在多反应离子监测(MRM)模式下检测,内标法定量.目标物在各自浓度范围内线性关系良好(r2 ＞0.99),在10、20、50ng/mL 3个加标水平下的回收率为80.7％～ 128％,相对标准偏差(RSDs)为0.79％～6.5％,检出限(LOD)为0.05～2.1 ng/mL,定量下限(LOQ)为0.18～5.5 ng/mL.该方法简便陕捷,灵敏度高,可用于纸张中芳香胺的快速检测.

In this study, composite films of stearic acid–modified magnesium oxide whiskers (Sa–w-MgO)/poly-l-lactic acid (PLLA) were prepared through solution casting, and the in vitro degradation properties and cytocompatibility of the composites with different whisker contents were investigated. The results showed that the degradation behavior of the composite samples depended significantly on the whisker content, and the degradation rate increased with the addition of MgO content. Furthermore, the degradation of the composites with higher contents of whiskers was influenced more severely by the hydrophilicity and pH value, leading to more final weight loss, but the decomposition rate decreased gradually. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO whiskers through neutralization of the acidic product of PLLA degradation. The cytocompatibility of the composites also increased remarkably, as determined from the cell viability results, and was higher than that of PLLA at the chosen whisker content. This was beneficial for the cell affinity of the material, as it notably led to an enhanced biocompatibility of the PLLA, in favor of promoting cell proliferation, which significantly improved its bioactivity, as well.

The modified MgO nanoparticles (m-MgO-NPs) by a copolymer containing the malic acid and low molecular weight poly(L-lactide) (poly(L-lactide-co-malic acid), PLMA) have been successfully prepared. MgO nanoparticles (MgO-NPs) were coated by the PLMA and m-MgO-NPs were uniformly dispersed in the PLLA matrix to a novel biocomposite material (PLLA/m-MgO-NPs) with more excellent interface bonding and uniformer dispersion, compared to the PLLA/MgO-NPs. Compared to neat PLLA and PLLA/MgO-NPs film, the m-MgO-NPs not only shown the obvious neutralization effect on the acidic solution in the degradation of the PLLA and better hydrophilicity, but also exhibited the higher cell viability and decrease the toxicity to the cell in the degradation process of PLLA in vitro. In addition, m-MgO-NPs also reduced the degradation rate of the PLLA. The mechanisms for the excellent dispersion of nanoparticles, enhanced pH stability, reduced degradation rate of the PLLA and the cell viability in vitro in the case of PLLA/m-MgO-NPs have also been proposed and discussed in detail.