Comparative Electrocatalytic Oxygen Evolution Reaction Studies of Spinel NiFe_(2)O_(4) and Its Nanocarbon Hybrids

Electrocatalytic oxygen evolution reaction(OER)is one of the crucial reactions for converting renewable electricity into chemical fuel in the form of hydrogen.To date,there is still a challenge in designing ideal cost-effective OER catalysts with excellent activity and robust durability.The hybridization of transition metal oxides and carbonaceous materials is one of the most effective and promising strategies to develop high-performance electrocatalysts.Herein,this work synthesized hybrids of NiFe_2 O_4 spinel materials with two-dimensional(2D)graphene oxide and one-dimensional(1 D)carbon nanotubes using a facile solvothermal approach.Electrocatalytic activities of NiFe_(2)O_(4) with 2 D graphene oxide toward OER were realized to be superior even to the 1 D carbon nanotube-based electro catalyst in terms of overpotential to reach a current density of10 mA/cm^(2) as well as Tafel slopes.The NiFe_(2)O_(4) with 2 D graphene oxide hybrid exhibits good stability with an overpotential of 327 mV at a current density of 10 mA/cm^(2) and a Tafel slope of 103 mV/dec.The high performance of NiFe_(2)O_(4) with 2 D graphene oxide is mainly attributed to its unique morphology,more exposed active sites,and a porous structure with a high surface area.Thus,an approach of hybridizing a metal oxide with a carbonaceous material offers an attractive platform for developing an efficient electrocatalyst for water electrochemistry applications.

States of Carbon Nanotube Supported Mo-Based HDS Catalysts

The dispersion of the active phase and loading capacity of the Mo species on carbon nanotube （CNT） was studied by the XRD technique. The reducibility properties of Co-Mo catalysts in the oxide state over CNTs were investigated by TPR, while the sulfided Co-Mo/CNT catalysts were characterized by means of the XRD and LRS techniques. The activity and selectivity with respect to the hydrodesulfurization （HDS） performances on carbon nanotube supported Co-Mo catalysts were evaluated. It was found that the main active molybdenum species in the oxide state MoO3/CNT catalysts were MoO2, but not MoO3, as generally expected. The maximum loading before the formation of the bulk phase was lower than 6% （percent by mass, based on MoO3）. TPR studies revealed that the active species in the oxide state Co-Mo/CNT catalysts were reduced more easily at relatively lower temperatures in comparison to those of the Co-Mo/γ-Al2O3 catalysts, indicating that the CNT support promoted or favored the reduction of the active species. The active species of a Co-Mo-0.7/CNT catalyst were more easily reduced than those of the Co-Mo/CNT catalysts with Co/Mo atomic ratios of 0.2, 0.35, and 0.5, respectively, suggesting that the Co/Mo atomic ratio has a great effect on the reducibility of the active species. It was found that the incorporation of cobalt improved the dispersion of the molybdenum species on the support, and a phenomenon of mobilization and re-dispersion had occurred during the sulfurization process, resulting in low valence state Mo3S4 and Co-MoS2.17 active phases. HDS measurements showed that the Co-Mo/CNT catalysts were more active than the Co-Mo/γ-Al2O3 ones for the desulfurization of DBT, and the hydrogenolysis/hydrogenation selectivity of the Co-Mo/CNT catalysts was also much higher than those of the Co-Mo/γ-Al2O3. The Co-Mo/CNT catalyst with a Co/Mo atomic ratio of 0.7 showed the highest activity, whereas the catalyst with a Co/Mo atomic ratio of 0.35 had the highest selectivity.

Heterocyclic compounds as key structures for the interaction with old and new targets in Alzheimer＇s disease therapy

Nowadays, Alzheimer＇s disease（AD） is widely recognized as a real social problem. In fact, only five drugs are FDA approved for the therapy of this widespread neurodegenerative disease, but with low results so far. Three of them（rivastigmine, donepezil and galantamine） are acetylcholinesterase inhibitors, memantine is a N-methyl-D-aspartate receptor antagonist, whereas the fifth formulation is a combination of donepezil with memantine. The prevention and treatment of AD is the new challenge for pharmaceutical industry, as well as for public institutions, physicians, patients, and their families. The discovery of a new and safe way to cure this neurodegenerative disease is urgent and should not be delayed further. Because of the multiple origin of this pathology, a multi-target strategy is currently strongly pursued by researchers. In this review, we have discussed new structures designed to better the activity on the classical AD targets. We have also examined old and new potential drugs that could prove useful future for the therapy of the pathology by acting on innovative, not usual, and not yet fully explored targets like peroxisome proliferator-activated receptor（PPARs）.

Recent progress in porous organic polymers and their application for CO_(2) capture

Carbon capture,storage,and utilization(CCSU)is recognized as an effective method to reduce the excessive emission of CO_(2).Absorption by amine aqueous solutions is considered highly efficient for CO_(2) capture from the flue gas because of the large CO_(2) capture capacity and high selectivity.However,it is often limited by the equipment corrosion and the high desorption energy consumption,and adsorption of CO_(2) using solid adsorbents has been receiving more attention in recent years due to its simplicity and high efficiency.More recently,a great number of porous organic polymers(POPs)have been designed and constructed for CO_(2) capture,and they are proven promising solid adsorbents for CO_(2) capture due to their high Brunauer-Emmett-Teller(BET)surface area(SBET),adjustable pore size and easy functionalization.In particular,they usually have rigid skeleton,permanent porosity,and good physiochemical stability.In this review,we have a detailed review for the different POPs developed in recent years,not only the design strategy,but also the special structure for CO_(2) capture.The outlook of the opportunities and challenges of the POPs is also proposed.

A New Approach to Plasma CVD of TiO_2 Photocatalyst on γ-Al_2O_3 Pellet Filled in Dielectric Barrier Discharges at Atmospheric Pressure

A supported TiO2/γ-Al2O3 photocatalyst has been prepared by γ-Al2O3 pellet-filled dielectric barrier discharges induced plasma CVD at atmospheric pressure and room temperature. The TiO2/γ-Al2O3 photocatalyst exhibits higher photocatalytic activity than Degussa P25, and much higher photocatalytic activity than that prepared by thermal CVD.

Catalytic ativities of single-atom catalysts for CO oxidation: Pt_1/FeO_x vs. Fe_1/FeO_x

An FeOx‐based Pt single‐atom catalyst(SAC),Pt1/FeOx,has stimulated significant recent interest owing to its extraordinary activity toward CO oxidation.The concept of SAC has also been successfully extended to other FeOx supported transition metal systems both experimentally and theoretically.However,the FeOx substrate itself(denoted by Fe1/FeOx following the same nomenclature of Pt1/FeOx)as a typical transition metal oxide possesses a very low catalytic activity toward CO oxidation,although it can be viewed as Fe1/FeOx SAC.Here,to understand the catalytic mechanism of FeOx‐based SACs for CO oxidation,we have performed density functional theory calculations on Pt1/FeOx and Fe1/FeOx for CO oxidation to address the differences between these two SACs in terms of the catalytic mechanism of CO oxidation and the chemical behavior of the catalysts.Our calculation results indicated that the catalytic cycle of Fe1/FeOx is much more difficult to accomplish than that of SAC Pt1/FeOx because of a high activation barrier(1.09eV)for regeneration of the oxygen vacancy formed when the second CO2molecule desorbs from the surface.Moreover,density of states and Bader charge analysis revealed differences in the catalytic performance for CO oxidation by the SACs Fe1/FeOx and Pt1/FeOx.This work provides insights into the fundamental interactions between the single‐atom Pt1and FeOx substrate,and the exceptional catalytic performance of this system for CO oxidation.

Investigation of water adsorption and dissociation on Au_1/CeO_2 single-atom catalysts using density functional theory

We examined the water adsorption and dissociation on ceria surfaces as well as ceria‐supported Au single‐atom catalysts using density functional theory calculations.Molecular and dissociative water were observed to coexist on clean CeO2and reduced Au1/CeO2?x surfaces because of the small difference in adsorption energies,whereas the presence of dissociative water was highly favorable on reduced CeO2?x and clean Au1/CeO2surfaces.Positively charged Au single atoms on the ceria surface not only provided activation sites for water adsorption but also facilitated water dissociation by weakening the intramolecular O-H bonds.In contrast,negatively charged Au single atoms were not reactive for water adsorption because of the saturation of Au5d and6s electron shells.This work provides a fundamental understanding of the interaction between water and single‐atom Au catalysts.

A comprehensive review of pre-lithiation/sodiation additives for Li-ion and Na-ion batteries

Lithium/Sodium-ion batteries(LIB/SIB)have attracted enormous attention as a promising electrochemical energy storage system due to their high energy density and long cycle life.One of the major hurdles is the initial irreversible capacity loss during the first few cycles owing to forming the solid electrolyte interphase layer(SEI).This process consumes a profusion of lithium/sodium,which reduces the overall energy density and cycle life.Thus,a suitable approach to compensate for the irreversible capacity loss must be developed to improve the energy density and cycle life.Pre-lithiation/sodiation is a widely accepted process to compensate for the irreversible capacity loss during the initial cycles.Various strategies such as physical,chemical,and electrochemical pre-lithiation/sodiation have been explored;however,these approaches add an extra step to the current manufacturing process.Alternative to these strategies,pre-lithiation/sodiation additives have attracted enormous attention due to their easy adaptability and compatibility with the current battery manufacturing process.In this review,we consolidate recent developments and emphasize the importance of using pre-lithiation/sodiation additives(anode and cathode)to overcome the irreversible capacity loss during the initial cycles in lithium/sodium-ion batteries.This review also addresses the technical and scientific challenges of using pre-lithiation/sodiation additives and offers the insights to boost the energy density and cycle life with their possible commercial exploration.The most important prerequisites for designing effective pre-lithiation/sodiation additives have been explored and the future directions have been discussed.

Phytochemical composition of Caesalpinia crista extract as potential source for inhibiting cholinesterase and β-amyloid aggregation: Significance to Alzheimer's disease

Objective: To screen plant extract fractions and elucidate the components present in Caesalpinia crista(C. crista) leaves for cholinergic and anti-amyloidogenic activities for the treatment of Alzheimer's diseases. Methods: This work has been carried out to study the action of C. crista extracts from nonpolar to polar solvents toward inhibition of oxidative stress, cholinergic and amyloidosis. The antioxidant activity was studied using DPPH total antioxidant assay; cholinergic assay by Ellman's method and anti-amyloidogenic assay by thioflavin-T fluorescence and transmission electron microscopy. Results: The quantification of polyphenols was carried out following C. crista methanolic extract(CCMeOH) HPLC fingerprinting, along with LC-MS and elucidated by MS LAMPS database. GC-MS of CCMeOH was screened for potential moieties. In vitro experimental results showed that the CCMe OH was potential extract that exhibited active inhibition of antioxidant property, cholinergic enzymes acetylcholinesterase and butyrylcholinesterase. For anti-amyloidogenic evaluations, among all the extracts, the CCMe OH was found to have the potential toward inhibiting the oligomers, fibrillation of Aβ42 with good defibrillation of amyloid cascading properties. Conclusions: These results are also supported by the presence of polyphenols as the active ingredients. Multi-potent target drug therapy is a promising option in treating the Alzheimer's diseases. Methanolic extract of C. crista shows potential activity against cholinergic enzymes, Aβ42 aggregation with antioxidant activity.

Plasma-Assisted Chemical Vapor Deposition of Titanium Oxide Films by Dielectric Barrier Discharge in TiCl_4/O_2/N_2 Gas Mixtures

Low-pressure dielectric barrier discharge（DBD） TiCl4/O2and N2 plasmas have been used to deposit titanium oxide films at different power supply driving frequencies. A homemade large area low pressure DBD reactor was applied, characterized by the simplicity of the experimental set-up and a low consumption of feed gas and electric power, as well as being easy to operate. Atomic force microscopy, scanning electron microscopy, energy dispersive spectroscopy,and contact angle measurements have been used to characterize the deposited films. Experimental results show all deposited films are uniform and hydrophilic with a contact angle of about 15 o.Compared to titanium oxide films deposited in TiCl4/O2gas mixtures, those in TiCl4/O2/N2gas mixtures are much more stable. The contact angle of titanium oxide films in TiCl4/O2/N2gas mixtures with the addition of 50% N2 and 20% TiCl4 is still smaller than 20 o, while that of undoped titanium oxide films is larger than 64 owhen they are measured after one week. The low-pressure TiCl4/O2plasmas consist of pulsed glow-like discharges with peak widths of several microseconds, which leads to the uniform deposition of titanium oxide films. Increasing a film thickness over several hundreds of nm leads to the film’s fragmentation due to the over-high film stress. Optical emission spectra（OES） of TiCl4/O2DBD plasmas at various power supply driving frequencies are presented.

吕坚院士寄语:重庆大学90周年校庆和NMS期刊发展

主持嘉宾:重庆大学材料科学与工程学院教授,Nano Materials Science执行副主编。张育新:您对重庆大学的发展以及我们的青年教师有什么真诚的建议?吕坚:首先祝贺重庆大学建校90周年!重庆在西部地区是一个非常重要的直辖市,对西部的发展有非常重要的作用。重庆大学作为重庆唯一一所国家“985工程”重点建设大学,是非常重要的,办好一所大学最重要的是老师,我很高兴我们团队的两位博士和博士后在贵校任职。张育新:青年老师刚刚走上工作岗位应该如何去发展,您有什么样的技巧分享给大家吗?

Efficient and recyclable palladium enriched magnetic nanocatalyst for reduction of toxic environmental pollutants

In this paper,highly stable,powerful,and recyclable magnetic nanoparticles tethered Nheterocyclic carbene-palladium(Ⅱ)((CH_(3))_(3)-NHC-Pd@Fe_(3)O_(4))as magnetic nanocatalyst was successfully synthesized from a simplistic multistep synthesis under aerobic conditions through easily available low-cost chemicals.Newly synthesized(CH_(3))_(3)-NHC-Pd@Fe_(3)O_(4) magnetic nanocatalyst was characterized from various analytical tools and catalytic potential of the(CH_(3))_(3)-NHC-Pd@Fe_3 O_4 magnetic nanocatalyst was studied for the catalytic reduction of toxic 4-nitrophenol(4-NP),hexavalent chromium(Cr(Ⅵ)),Methylene Blue(MB)and Methyl Orange(MO)at room temperature in aqueous media.UV-Visible spectroscopy was employed to monitor the reduction reactions.New(CH_(3))_(3)-NHC-Pd@Fe_(3)O_(4) magnetic nanocatalyst exhibited excellent catalytic activity for the reduction of toxic environmental pollutants.Moreover,(CH_(3))_(3)-NHC-Pd@Fe_(3)O_(4) magnetic nanocatalyst could be easily and rapidly separated from the reaction mixture with the help of an external magnet and recycled minimum five times in reduction of 4-NP,MB,MO and four times in Cr(Ⅵ)without significant loss of catalytic potential and remains stable even after reuse.

Fundamentals and comprehensive insights on pulsed laser synthesis of advanced materials for diverse photo-and electrocatalytic applications

The global energy crisis is increasing the demand for innovative materials with high purity and functionality for the development of clean energy production and storage.The development of novel photo-and electrocatalysts significantly depends on synthetic techniques that facilitate the production of tailored advanced nanomaterials.The emerging use of pulsed laser in liquid synthesis has attracted immense interest as an effective synthetic technology with several advantages over conventional chemical and physical synthetic routes,including the fine-tuning of size,composition,surface,and crystalline structures,and defect densities and is associated with the catalytic,electronic,thermal,optical,and mechanical properties of the produced nanomaterials.Herein,we present an overview of the fundamental understanding and importance of the pulsed laser process,namely various roles and mechanisms involved in the production of various types of nanomaterials,such as metal nanoparticles,oxides,non-oxides,and carbon-based materials.We mainly cover the advancement of photo-and electrocatalytic nanomaterials via pulsed laser-assisted technologies with detailed mechanistic insights and structural optimization along with effective catalytic performances in various energy and environmental remediation processes.Finally,the future directions and challenges of pulsed laser techniques are briefly underlined.This review can exert practical guidance for the future design and fabrication of innovative pulsed laser-induced nanomaterials with fascinating properties for advanced catalysis applications.

Pd/Fe_(3)O_(4) supported on bio-waste derived cellulosic-carbon as a nanocatalyst for C-C coupling and electrocatalytic application

The current work describes the synthesis of a new bio-waste derived cellulosic-carbon supportedpalladium nanoparticles enriched magnetic nanocatalyst(Pd/Fe_(3)O_(4)@C)using a simple multi-step process under aerobic conditions.Under mild reaction conditions,the Pd/Fe_(3)O_(4)@C magnetic nanocatalyst demonstrated excellent catalytic activity in the Hiyama cross-coupling reaction for a variety of substrates.Also,the Pd/Fe_(3)O_(4)@C magnetic nanocatalyst exhibited excellent catalytic activity up to five recycles without significant catalytic activity loss in the Hiyama cross-coupling reaction.Also,we explored the use of Pd/Fe_(3)O_(4)@C magnetic nanocatalyst as an electrocatalyst for hydrogen evolution reaction.Interestingly,the Pd/Fe_(3)O_(4)@C magnetic nanocatalyst exhibited better electrochemical activity compared to bare carbon and magnetite(Fe_(3)O_(4)nanoparticles)with an overpotential of 293 mV at a current density of 10 mA·cm^(–2).

Rauvolfia serpentina-Mediated Green Synthesis of CuO Nanoparticles and Its Multidisciplinary Studies

Copper oxide nanoparticles （CuO Nps） were successfully synthesized by solution combustion method using aqueous leaf extract of Rauvolfia serpentina as a fuel. The structure and morphology of the CuO nanoparticles （Nps） were characterized by powder X-ray diffraction （PXRD）, UV-visible spectroscopy （UV-visible）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, etc. The PXRD patterns reveal the formation of monoclinic phase with crystallite structure. SEM images indicate that the particles have sponge-like structure being highly porous and agglom- erated with large surface area. The average crystallite sizes were found to be in the range of 10-20 nm by Scherrer＇s method. The CuO Nps size was further confirmed by TEM. Further, CuO Nps exhibit good photocatalytic activity for the photodegradation of trypan blue dye, indicating that it acts as a promising semiconducting material. The antibacterial properties of CuO nanoparticles were investigated against pathogenic bacterial strains, namely Gram -ve Escherichia coli （NCIM-5051） and Pseudomonas desmolyticum （NCIM-2028） and Gram ＋ve bacteria Staphylococcus aureus （NCIM- 5022） using the agar well diffusion method.

Recent developments in synthesis,properties,and applications of 2D Janus MoSSe and MoS_(x)Se_((1-x))alloys

The Janus MoSSe and alloy MoS_(x)Se_((1-x)),belonging to the family of two-dimensional(2D)transition metal dichalcogenides(TMDs),have gained significant attention for their potential applications in nanotechnology.The unique asymmetric structure of Janus MoSSe provides intriguing possibilities for tailored applications.The alloy MoS_(x)Se_((1-x))offers a tunable composition,allowing for the fine-tuning of the properties to meet specific requirements.These materials exhibit remarkable mechanical,electrical,and optical properties,including a tunable band gap,high absorption coefficient,and photoconductivity.The vibrational and magnetic properties also make it a promising candidate for nanoscale sensing and magnetic storage applications.Properties of these materials can be precisely controlled through different approaches such as size-dependent properties,phase engineering,doping,alloying,defect and vacancy engineering,intercalation,morphology,and heterojunction or hybridisation.Various synthesis methods for 2D Janus MoSSe and alloy MoS_(x)Se_((1-x))are discussed,including hydro/solvothermal,chemical vapour transport,chemical vapour deposition,physical vapour depositio,and other approaches.The review also presents the latest advancements in Janus and alloy MoSSe-based applications,such as chemical and gas sensors,surface-enhanced Raman spectroscopy,field emission,and energy storage.Moreover,the review highlights the challenges and future directions in the research of these materials,including the need for improved synthesis methods,understanding of their stability,and exploration of new applications.Despite the early stages of research,both the MoSSe-based materials have shown significant potential in various fields,and this review provides valuable insights for researchers and engineers interested in exploring its potential.

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated.The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscopeenergy dispersive X-ray spectroscopy,Fourier transform infrared spectroscopy,Brunauer–Emmett–Teller surface area,thermogravimetric analysis and n-butylamine acidity.The shape of catalysts particles plays an important role in its activity.The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production.The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid,oleic acid with methanol.The effect of various reaction parameters such as catalyst concentration,acid/alcohol molar ratio,catalyst amount,reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion.It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts.Additionally,the catalyst was regenerated and reused up to three cycles without any significant loss in activity.The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock’s that are rich in free fatty acids.

Recent developments in self-powered smart chemical sensors for wearable electronics

The next generation of electronics technology is purely going to be based on wearable sensing systems. Wearable electronic sensors that can operate in a continuous and sustainable manner without the need of an external power sources, are essential for portable and mobile electronic applications. In this review article, the recent progress and advantages of wearable self-powered smart chemical sensors systems for wearable electronics are presented. An overview of various modes of energy conversion and storage technologies for self-powered devices is provided. Self-powered chemical sensors (SPCS) systems with integrated energy units are then discussed, separated as solar cell-based SPCS, triboelectric nano-generators based SPCS, piezoelectric nano-generators based SPCS, energy storage device based SPCS, and thermal energy-based SPCS. Finally, the outlook on future prospects of wearable chemical sensors in self-powered sensing systems is addressed.

Dual functions:A coumarin–chalcone conjugate inhibits cyclic-di-GMP and quorum-sensing signaling to reduce biofilm formation and virulence of pathogens

Antibiotic resistance or tolerance of pathogens is one of the most serious global public health threats.Bacteria in biofilms show extreme tolerance to almost all antibiotic classes.Thus,use of antibiofilm drugs without bacterial-killing effects is one of the strategies to combat antibiotic tolerance.In this study,we discovered a coumarin–chalcone conjugate C9,which can inhibit the biofilm formation of three common pathogens that cause nosocomial infections,namely,Pseudomonas aeruginosa,Staph-ylococcus aureus,and Escherichia coli,with the best antibiofilm activity against P.aeruginosa.Further investigations indicate that C9 decreases the synthesis of the key biofilm matrix exopolysaccharide Psl and bacterial second messenger cyclic-di-GMP.Meanwhile,C9 can interfere with the regulation of the quorum sensing(QS)system to reduce the virulence of P.aeruginosa.C9 treatment enhances the sensitivity of biofilm to several antibiotics and reduces the survival rate of P.aeruginosa under starvation or oxidative stress conditions,indicating its excellent potential for use as an antibiofilm-forming and anti-QS drug.

Potential metal-related strategies for prevention and treatment of COVID-19

The coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has posed severe threats to human health,public safety,and the global economy.Metal nutrient elements can directly or indirectly take part in human immune responses,and metal-related drugs have served as antiviral drugs and/or enzyme inhibitors for many years,providing potential solutions to the prevention and treatment of COVID-19.Metal-based drugs are currently under a variety of chemical structures and exhibit wide-range bio activities,demonstrating irreplaceable advantages in pharmacology.This review is an intention to summarize recent progress in the prevention and treatment strategies against COVID-19 from the perspective of metal pharmacology.The current and potential utilization of metal-based drugs is briefly introduced.Specifically,metallohydrogels that have been shown to present superior antiviral activities are stressed in the paper as potential drugs for the treatment of COVID-19.