Synergetic effect between sulfurized Mo/γ-Al_2O_3 and Ni/γ-Al_2O_3 catalysts in hydrodenitrogenation of quinoline

An evidence for the synergetic effect between the stacked bed of Mo/γ-Al2O3 and Ni/γ-Al2O3 in the hydrodenitrogenation （HDN） reaction of quinoline has been provided in this paper. The synergism factor decreases when the reaction temperature increases （280？340 ？C）. The synergetic effect leads to improve the hydrogenation activity for the stacked bed compared with the single Mo/γ-Al2O3 bed, which may be attributed to the generation of hydrogen spillover on the Ni/γ-Al2O3 catalyst.

Synergetic Effects of UV/Fe^(3+) Combined with Electrocatalysis for p-Nitrophenol Degradation

Synergetic effects for p-nitrophenol degradation were observed in the combination of two-advanced oxidation processes, UV/Fe3+ and electrocatalysis. The enhancement of removal rate for p-nitrophenol and COD was around 123% and 278%, respectively. The possible contributions for the synergetic effects were the electrochemically regeneration of ferric ion and the role of the oxygen that formed on the anode.

Synergetic effects of NaAlH_4-TiF_3 co-additive on dehydriding reaction of Mg(AlH_4)_2

The effects of NaA1H4, TiF3 and NaA1H4-TiF3 co-additive on dehydriding reaction of Mg（A1H4）2 are systematically investigated. The on- set dehydrogenation temperature of the co-doped Mg（A1H4）2 composites decreased to 74 ℃, which is about 59 ℃ lower than that of pure Mg（A1H4）2. The dehydrogenation kinetics of NaA1H4-TiF3 co-doped Mg（A1H4）2 sample was also improved, which released about 94% hydrogen within 48 min, but no visible hydrogen was released from pure Mg（A1H4）2 under the same conditions. The activation energy of co-doped Mg（A1H4）2 was 85.6 kJ.mol-t, which was significantly lower than that of additive-free Mg（A1H4）2 sample. The synergetic effects of NaA1H4 and TiF3 on the dehydrogenation performance of Mg（A1H4）2 were confirmed. In addition, a possible catalytic mechanism is discussed, regarding the different roles of NaA1H4 and TiF3 on Mg（A1H4）2.

Modeling the Synergetic Effect of Various Factors on Chloride Transport in Nonsaturated Concrete

Diffusion has been systematically described as the main mechanism of chloride transport in reinforced concrete（RC） structure, especially when the concrete is in a saturated state. However, the single mechanism of diffusion is not able to describe the actual chloride ingress in the nonsaturated concrete. Instead, it is dominated by the interaction of diffusion and convection. With the synergetic effects of various factors taken into account, this study aimed to modify and develop an analytical convection- diffusion coupling model for chloride transport in nonsaturated concrete. The model was verified by simulation of laboratory tests and field measurement. The results of comparison study demonstrate that the analytical model developed in this study is efficient and accurate in predicting the chloride profiles in the nonsaturated concrete.

Enhancing oxygen reduction reaction of Pt-Co/C nanocatalysts via synergetic effect between Pt and Co prepared by one-pot synthesis

Designing highly active and durable electrocatalysts towards oxygen reduction reaction(ORR)plays a paramount importance for proton exchange membrane fuel cells.Pt-based binary alloys Pt-M(M=3d-transition metals)possessing excellent electronic and geometric properties have received increasing interests as highly active electrocatalysts.Herein,we report a series of Pt_(x)Co/C(x=1,2,3)catalysts by a facile one-pot soft-chemistry method.In the acidic conditions,the mass activities of PtCo/C,Pt_(2)Co/C and Pt_(3)Co/C are 0.526,0.462 and 0.441 A·mgPt^(-1),which are 2.60,2.31 and 2.22 times higher than that of Pt/C(0.200 A·mgPt^(-1)),respectively.The specific activities of PtCo/C,Pt_(2)Co/C and Pt_(3)Co/C are 706.59,679.41 and 801.83μA·cm^(-2),which are accordingly 2.89,2.76 and 3.28 times higher than that of Pt/C(244.75μA·cm^(-2)).Notably,Pt_(3)Co/C shows a remarkable durability.After 5000 cycles of the accelerated durability testing,the mass activity and specific activity of Pt_(3)Co/C catalyst are 2.47 and 3.80 times higher than that of the commercial Pt/C,respectively.The improved ORR activity and durability can be ascribed to the synergistic interaction between Pt and Co.

Influence of H_(2)S and NH_(3) on biogas dry reforming using Ni catalyst:a study on single and synergetic effect

Biogas is a renewable biomass energy source mainly composed of CH4 and CO_(2).Dry reforming is a promising technology for the high-value utilization of biogas.Some impurity gases in biogas can not be completely removed after pretreatment,which may affect the performance of dry reforming.In this study,the influence of typical impurities H_(2)S and NH_(3) on dry reforming was studied using Ni/MgO catalyst.The results showed that low concentration of H_(2)S in biogas could cause serious deactivation of catalyst.Characterization results including EDS,XPS and TOF-SIMS confirmed the adsorption of sulfur on the catalyst surface,which was the cause of catalyst poisoning.We used air calcination method to regenerate the sulfur-poisoned catalysts and found that the regeneration temperature higher than 500℃could help catalyst recover the original activity.NH_(3)in the concentration range of 50–10000 ppm showed a slight inhibitory effect on biogas dry reforming.The decline rate of biogas conversion efficiency increased with the increase of NH_(3) concentration.This was related to the reduction of oxygen activity on catalyst surface caused by NH_(3).The synergetic effect of H_(2)S and NH_(3)in biogas was investigated.The results showed that biogas conversion decreased faster under the coexistence of H_(2)S and NH_(3)than under the effect of H_(2)S alone,so as the surface oxygen activity of catalyst.Air calcination regeneration could also recover the activity of the deactivated catalyst under the synergetic effect of H_(2)S and NH_(3).

Stratosphere-troposphere synergetic effect on the extreme low-temperature event over China in late November 2022

In late November 2022,most regions in China were hit by a strong northwest-path cold wave,bringing a high-hazard extreme low-temperature event(ELTE).Several parts of Northwest China experienced extremely low temperatures and record-breaking snow depths.A stratosphere-troposphere synergetic effect was suggested to be closely related to the ELTE according to a diagnostic analysis.On the one hand,the concurrent establishment of two blockings in Europe-Northeast Atlantic and North Pacific led to a polar vortex split at the tropopause,and the Arctic Oscillation phase subsequently turned negative.An airflow with high potential vorticity(PV)was squeezed out of the Arctic.Meanwhile,a high-PV air that originated from the lower stratospheric Arctic was conveyed southwards to the western Siberian Plain along the sloping isentropic surface.This condition triggered a tropospheric response in which the East Asia trough deepened due to the intensified cyclonic circulation induced by the high-PV intrusion.On the other hand,downward propagation of stratospheric anomalies accompanied by stratospheric polar vortex displacement and split was observed in mid-and late November,respectively.Changes in stratospheric circulation contributed to enhanced blockings over Europe-Northeast Atlantic in the lower stratosphere or upper troposphere.As a result,the inverted omega-shaped circulation pattern was formed in the middle to upper troposphere,and it consisted of the intensified East Asia trough and two blockings in the upstream and downstream regions.The high-PV air upstream of the East Asia trough was advected to China,which directly led to the outbreak of the ELTE.The establishment of double blockings and the displacement or split of the stratospheric polar vortex can be efficient signals for cold-event prediction in China.This study provides novel insights into the cause of ELTEs under warming climates in the future.

Synergetic effects of lanthanum,nitrogen and phosphorus tri-doping on visiblelight photoactivity of TiO_2 fabricated by microwave-hydrothermal process

Effects of La, N, and P doping on the structural, electronic and optical properties of TiO_2 synthesized from TiCl_4 hydrolysis via a microwave-hydrothermal process were investigated by X-ray diffraction, transmission electron microscopy, N_2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy, electron paramagnetic resonance, UV-vis absorbance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy. The results showed that the presence of La in the tri-doped TiO_2 played a predominant role in inhibiting the recombination of the photogenerated electrons and holes. The existence of the substitutional N, interstitial N, and oxygen vacancies in TiO_2 lattices led to the band gap narrowing. It was P-doping rather than La or N doping that played a key role in inhibiting both anatase-to-rutile phase transformation and crystal growth, in stabilizing the mesoporous textural properties, and in increasing the content of surface bridging hydroxyl. Moreover, the tri-doping significantly enhanced the surface Ti^（4＋）-O^（2-）-Ti^（4＋）-O^（-·） species. All above-mentioned factors cooperated to result in the enhanced photoactivity of the tri-doped TiO_2. As a result, it exhibited the highest photoactivity towards the degradation of 4-chlorophenol（4-CP） under visible-light irradiation among all samples, which was much superior to commercial P25 TiO_2.

Synergetic effect of thermo-photocatalytic oxidation of benzene on Pt-TiO_2/Ce-MnO_x

Pt-TiO2/Ce-MnOx catalysts were obtained by depositing TiO2 and platinum, respectively, on the Ce-Mn oxides prepared by co-precipitation method. The phases of CeO2 and anatase TiO2 were observed in the catalysts from X-ray diffraction （XRD） patterns. X-ray photoelectron spectroscopy （XPS） revealed that lattice oxygen and surface active oxygen were found to be the major components of O 1 s. The experiment results showed that the kinetic constant of thermo-photocatalysis was 7.6 times of the kinetic constant of single photocatalysis, and was 2.29 times of the kinetic constant sum of photocatalytic and thermal catalytic reaction.

Electrochemical characteristics and synergetic effect of Ti_(0.10)Zr_(0.15)V_(0.35)Cr_(0.10)Ni_(0.30)-10 wt.%LaNi_5 hydrogen storage composite electrode

In order to improve performance of Ti-V-based solid solution alloy, electrochemical characteristics and synergetic effect of Ti0.10Zr0.15V0.35Cr0.10Ni0.30-10 wt.%LaNi5 hydrogen storage composite electrode prepared by two-step arc-melting were investigated system-atically. X-ray diffractometry （XRD） and scanning electron microscopy-energy dispersive spectroscopy （SEM-EDS） showed that the main phase of composite alloy was composed of V-based solid solution phase with a BCC structure and C14 Laves phase with hexagonal structure, while secondary phase also existed in the composite alloy. The results showed that electrochemical characteristics of the composite alloy elec-trode were significantly improved. It was suggested that synergetic effect appeared in the maximum discharge capacity of the composite alloy, synergetic effect of the discharge capacity appeared in the activation process, in the composite process, in the cyclic process, in the discharge process at low/high temperature and at different current densities, and synergetic effect existed in the charge-transfer resistance and in the ex-change current density, which seemed to be related to formation of the secondary phase.

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.

Visible Light-Induced Photocatalysis:Self-Fenton Degradation of p-CIPhOH Over Graphitic Carbon Nitride by a Polyethylenimine Bifunctional Catalyst

Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.

Synergetic strengthening mechanism of ultrasound combined with calcium fluoride towards vanadium extraction from low-grade vanadium-bearing shale

The effect and mechanism of ultrasound and CaF_(2) on vanadium leaching from vanadium-bearing shale were investigated systematically.In consideration of the enhancement for vanadium recovery,the combination of ultrasound and CaF_(2)(66.28%) exerts more evident effects than ultrasound(26.97%) and CaF_(2)(60.35%) alone,demonstrating the synergetic effect of ultrasound and CaF_(2).Kinetic analysis manifests that the product layer diffusion controls vanadium leaching in ultrasound system without CaF_(2),however product layer diffusion and interfacial reaction is the rate-controlling step for vanadium leaching in other three leaching systems.The combination of ultrasound and CaF_(2) notably decreases the activation energy(E_(a)) from 62.03 to 27.61 kJ/mol,nevertheless individual CaF_(2) only reduces the E_(a) to 50.70 kj/mol.X-ray diffraction and fourier transform infrared spectrometer analyses show that the decomposition degree of the vanadium-bearing mica structure is the most significant in ultrasound and CaF_(2) system,proving the highest release degree of vanadium.Specific surface area and pore distribution combined with scanning electron microscope analyses reveal that the action of ultrasound and CaF_(2) would provide higher specific surface area,more abundant pores structure and cracks for the particles,which further prompts the rapid diffusion of H^(+),F^(-)and HF,and achieves the conspicuous improvement of vanadium leaching recovery.

Recent Advances on Porous Materials for Synergetic Adsorption and Photocatalysis

Porous photocatalysts are promising materials capable of simultaneously adsorbing and oxidizing/reducing target species,showing great potentials in environmental remediation and energy generation.This review offered a comprehensive overview of the recent progress in design,fabrication,and applications of porous photocatalysts,including carbon-based semiconductors,metal oxides/sulfides,metal–organic frameworks,and adsorbent–photocatalyst hybrids.The fundamental understanding of the structure–performance relationships of porous materials together with the in-depth insights into the synergetic effects between adsorption and photocatalysis was presented.The strategies to further improve the photocatalytic activity of porous photocatalysts were proposed.This review would provide references and outlooks of constructing efficient porous materials for adsorptive and photocatalytic removal of pollutants and energy production.

Synergetic Inactivation of Microorganisms in Drinking Water by Short-term Free Chlorination and Subsequent Monochloramination

Objective To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects： free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

Magnetic, dielectric and luminescence synergetic switchable effects in molecular material [Et_(3)NCH_(2)Cl]_(2)[MnBr_(4)]

The application of multifunctional materials in various fields such as electronics and signal processors has attracted massive attention. Herein, a new organic-inorganic hybrid material [Et_(3)NCH_(2)Cl]_(2)[MnBr_(4)](1) is reported, which contains two organic amines cations and one [MnBr_(4)] tetrahedral ion. Compound 1 has a dielectric anomaly signal at 338 K, which proves its thermodynamic phase transition. The single crystal measurements at 200 K and 380 K show that the phase transition of compound 1 is caused by the thermal vibration of organic amine cations in the lattice. Moreover, compound 1 shows yellow-green luminescence under UV light irradiation. The magnetism measurements indicate that compound 1 shows switchable magnetic properties. This organic–inorganic material is a multifunctional material with dielectric, optical, and magnetic synergetic switchable effects, which expands a new direction for designing multifunctional materials.

Monodispersed ultrathin twisty PdBi alloys nanowires assemblies with tensile strain enhance C_(2+)alcohols electrooxidation

Direct alcohol fuel cells(DAFCs)are powered by the alcohol electro-oxidation reaction(AOR),where an electrocatalyst with an optimal electronic structure can accelerate the sluggish AOR.Interestingly,strain engineering in hetero-catalysis offers a promising route to boost their catalytic activity.Herein,we report on a class of monodispersed ultrathin twisty PdBi alloy nanowires(TNWs)assemblies with face-centered structures that drive AORs.These thin nanowire structures expose a large number of reactive sites.Strikingly,Pd_(6)Bi_(1)TNWs show an excellent current density of 2066,3047,and 1231 mA mg_(Pd)^(-1)for oxidation of ethanol,ethylene glycol,and glycerol,respectively.The“volcano-like”behaviors observed on PdBi TNWs for AORs indicate that the maximum catalytic mass activity is a well balance between active intermediates and blocking species at the interface.This study offers an effective and universal method to build novel nanocatalysts in various applications by rationally designing highly efficient catalysts with specific strain.

Enabling tandem oxidation of benzene to benzenediol over integrated neighboring V-Cu oxides in mesoporous silica

The direct tandem oxidation synthesis of benzenediol from benzene could simplify or even avoid the separation and purification of reaction intermediates, which is promising but challenged because of the further required immediate consecutive activation of intermediate phenol. In this work, a synergistic benzene tandem-oxidation catalyst that V-Cu bimetallic oxides modified nanoporous silica(VCu-NS)was constructed via a facile assembly strategy which involves addictive negative anion citric acid mediating the intercalation of metal-citric acid chelate in mesopore of silica and subsequent thermal calcination inducing dual-metal active site formation. Such a tactic could make amorphous VOxspecies well covered on the surface of mesopore, and ultrafine copper oxide particles surrounded and neighbored by highly dispersed VOxwith strong interplay in mesopore, which was comprehensively confirmed by various characterizations. Benefiting from the unique V-Cu neighboring effect, the desorption of formed phenol over the catalytic site might be restricted therefore easily further activated by the formed reactive oxidative species, 3VCu-NS shows synergetic tandem-oxidation catalytic activities for benzene towards benzenediol with a selectivity of 57%. The result allows optimal 3VCu-NS to be a promising catalyst for benzenediol synthesis from benzene.

Improving plasma sterilization by constructing a plasma photocatalytic system with a needle array corona discharge and Au plasmonic nanocatalyst

Efficient sterilization by a plasma photocatalytic system(PPS)requires strong synergy between plasma and photocatalyst to inactivate microorganisms while suppressing the formation of secondary pollutants.Here,we report that a PPS constructed from a needle array corona discharge and Au/TiO2plasmonic nanocatalyst could remarkably improve the sterilization of Escherichia coli(E.coli)and alleviate formation of the discharge pollutant O3.At 6 kV,the combination of corona discharge and Au/TiO2achieves sterilization efficiency of 100%within an exposure time of 5 min.At 5 kV and an exposure time of 8 min,the presence of Au/TiO2improves sterilization efficiency of the corona discharge from 73%to 91%and reduces the O3concentration from 0.38 to 0.04 ppm,whereas the presence of TiO2reduces the sterilization efficiency and O3concentration to 66%and 0.17 ppm,respectively.The Au/TiO2in the PPS enables a uniform corona discharge,enhances the interaction between plasma,E.coli and nanocatalysts,and suppresses the formation of O3.Further,the Au/TiO2can be excited by ultraviolet-visible light emitted from the plasma to generate electron-hole pairs,and thus contributes to the formation of reactive radicals and the oxidative inactivation of E.coli.The PPS constructed from a needle array corona discharge and Au-based plasmonic nanocatalyst provides a promising approach for developing high-efficiency sterilization techniques.

Promoting CO_(2) and H_(2)O activation on O-vacancy regulated In-Ti dual-sites for enhanced CH_(4) photo-production

Engineering the specific active sites of photocatalysts for simultaneously promoting CO_(2)and H_(2)O activation is important to achieve the efficient conversion of CO_(2)to hydrocarbon with H_(2)O as a proton source under sunlight.Herein,we delicately design the In/TiO_(2)-VOphotocatalyst by engineering In single atoms(SAs)and oxygen vacancies(VOs)on porous TiO_(2).The relation between structure and performance of the photocatalyst is clarified by both experimental and theoretical analyses at the atomic levels.The In/TiO_(2)-VOphotocatalyst furnish a high CH_(4)production rate up to 35.49μmol g^(-1)h^(-1)with a high selectivity of 91.3%under simulated sunlight,while only CO is sluggishly generated on TiO_(2)-VO.The combination of in situ spectroscopic analyses with theoretical calculations reveal that the VOsites accelerate H_(2)O dissociation and increase proton feeding for CO_(2)reduction.Furthermore,the VOregulated In-Ti dual sites enable the formation of a stable adsorption conformation of In-C-O-Ti intermediate,which is responsible for the highly selective reduction of CO_(2)to CH_(4).This work demonstrates a new strategy for the development of effective photocatalysts by coupling metal SA sites with the adjacent metal sites of support to synergistically enhance the activity and selectivity of CO_(2)photoreduction.