Bimetallic CoNi single atoms supported on three-dimensionally ordered mesoporous chromia:highly active catalysts for n-hexane combustion

Developing the alternative supported noble metal catalysts with low cost,high catalytic efficiency,and good resistance toward carbon dioxide and water vapor is critically demanded for the oxidative removal of volatile organic compounds(VOCs).In this work,we prepared the mesoporous chromia-supported bimetallic Co and Ni single-atom(Co_(1)Ni_(1)/meso-Cr_(2)O_(3))and bimetallic Co and Ni nanoparticle(Co_(NP)Ni_(NP)/mesoCr_(2)O_(3))catalysts adopting the one-pot polyvinyl pyrrolidone(PVP)-and polyvinyl alcohol(PVA)-protecting approaches,respectively.The results indicate that the Co_(1)Ni_(1)/meso-Cr_(2)O_(3)catalyst exhibited the best catalytic activity for n-hexane(C_(6)H_(14))combustion(T_(50%)and T_(90%)were 239 and 263℃ at a space velocity of 40,000 mL g^(-1)h^(-1);apparent activation energy and specific reaction rate at 260℃ were 54.7 kJ mol^(-1)and 4.3×10^(-7)mol g^(-1)_(cat)s^(-1),respectively),which was associated with its higher(Cr^(5+)+Cr^(6+))amount,large n-hexane adsorption capacity,and good lattice oxygen mobility that could enhance the deep oxidation of n-hexane,in which Ni_(1) was beneficial for the enhancements in surface lattice oxygen mobility and low-temperature reducibility,while Co_(1) preferred to generate higher contents of the high-valence states of chromium and surface oxygen species as well as adsorption and activation of n-hexane.n-Hexane combustion takes place via the Mars van Krevelen(MvK)mechanism,and its reaction pathways are as follows:n-hexane→olefins or 3-hexyl hydroperoxide→3-hexanone,2-hexanone or 2,5-dimethyltetrahydrofuran→2-methyloxirane or 2-ethyl-oxetane→acrylic acid→CO_x→CO_(2)and H_(2)O.

催化法治理挥发性有机物污染的研究进展

挥发性有机物(VOCs)具有毒性、刺激性、致癌性和致畸作用,主要来源于石油化工、制药、制鞋业、电子制造和餐饮油烟等人类活动.VOCs和NO_(x)是生成细颗粒物(PM2.5)和臭氧(O3)等二次污染物的重要前体物,严重制约了社会的可持续发展,并对人类健康构成了严重威胁.因此,治理VOCs污染对于降低环境风险至关重要.鉴于实际工况条件复杂,多种VOCs(烷烃、芳香烃、卤代烃、醛酮和醇酯等)共存,它们的极性和浓度存在差异,在催化剂上的吸附、活化和转化过程不同,因此,对催化剂高效消除多组分VOCs的能力提出了挑战.目前,在众多净化VOCs的技术中,催化氧化法因其高效率、低能耗等优势在末端污染控制中越来越受到重视.本文主要介绍了近十年来通过热催化或光热催化消除污染物的代表性研究工作.首先,系统地总结了用于热催化消除单一VOC和典型多组分VOCs(例如,医药行业:甲苯和丙酮;家具涂料行业:甲苯和异己烷等)、协同消除VOCs和NO_(x),以及VOCs资源化利用(选择催化转化VOCs为高附加值产品)而设计和制备的各种具有独特形貌和结构的过渡金属氧化物纳米催化剂、贵金属颗粒纳米催化剂、贵金属单原子催化剂等,并探讨了其氧化还原性、酸性、氧物种、载体孔结构、贵金属分散度等对催化活性和稳定性的影响机制及优化策略.其次,鉴于化石燃料的日益减少,本文还概述了光热协同催化技术,该技术结合了光催化和热催化技术,通过太阳光的光热转换,能够在较低的温度下高效催化消除VOCs,并介绍了其效率和转化机制.此外,文中还深入分析了H_(2)O,CO_(2)和SO_(2)等气体对催化稳定性的影响机制.最后,考虑到我国当前大气污染防治面临更为复杂的复合污染问题等挑战,对未来发展趋势提出了展望:(1)利用活性空间和活性位点分离策略协同催化净化VOCs和NO_(x),从而实现催化氧化和还原反应的高效进行.(2)聚焦于大气污染物和温室气体的协同处理,探究CO_(2)和VOCs协同转化的路径和效率,为减污降碳和实现碳中和提供新思路.(3)设计合成新型串联催化剂用于安全转化含CVOCs的多组分污染物,以实现VOCs污染广谱性控制.(4)发展先进的原位表征技术(如原位电子显微镜、同位素示踪技术、原位拉曼光谱、原位X射线光电子能谱等)以实时检测催化剂的原子结构变化、吸附VOCs分子降解的中间体变化等,并结合理论计算确定最优反应路径,从而指导催化剂的设计与优化.(5)深入研究外场(例如,光能、电能、磁能)耦合热催化降解VOCs的技术,以期实现反应条件更温和、反应速率更高的催化过程.综上,本文综述了通过实验和理论计算手段揭示催化剂消除VOCs污染的性能与构效关系的研究进展,系统地呈现了治理VOCs污染研究的基本逻辑和框架体系,以期为后续开发高活性、高稳定性和高选择性的催化剂及其工业化应用提供借鉴.

Catalytic performance enhancement by alloying Pd with Pt on ordered mesoporous manganese oxide for methane combustion

Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated and poly(vinyl alcohol)‐protected reduction methods, respectively.The meso‐Mn2O3 had a high surface area, i.e., 106 m2/g, and a cubic crystal structure. Noble‐metalnanoparticles (NPs) of size 2.1?2.8 nm were uniformly dispersed on the meso‐Mn2O3 surfaces. AlloyingPd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd5.1Pt)/meso‐Mn2O3gave the best performance; T10%, T50%, and T90% (the temperatures required for achieving methaneconversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of20000 mL/(g?h). The effects of SO2, CO2, H2O, and NO on methane combustion over1.41(Pd5.1Pt)/meso‐Mn2O3 were also examined. We conclude that the good catalytic performance of1.41(Pd5.1Pt)/meso‐Mn2O3 is associated with its high‐quality porous structure, high adsorbed oxygen species concentration, good low‐temperature reducibility, and strong interactions between Pd‐Pt alloy NPs and the meso‐Mn2O3 support.

Differences between physiological and pathological convulsive thresholds in patients with epilepsy

BACKGROUND： Physiological convulsive thresholds degrade when the brain is in some pathologic states; thus, a level of stimulus that cannot provoke a convulsion may evoke a seizure or epileptic seizure. OBJECTIVE： To investigate the changes that occur in the brain when the physiological convulsive threshold becomes pathological, and to determine what differences occur in pathological and physiological convulsive thresholds during the development of epilepsy. DESIGN： A randomized controlled animal experiment. SETTING： Research Institute of Epilepsy of Shanxi Medical University; Department of Neurology, The Third Hospital of Shanxi Medical University; Research Institute of Function of Shanxi Medical University. MATERIALS： Thirty-six female Wistar rats were selected for this study. The rats were obtained from the experimental animal center of Shanxi Medical University. All laboratory procedures complied with animal ethical standards. The animals were randomly divided into three groups： a strong current group, a weak current group and a control group, with 12 rats in each group. An automatic determinator of seizure threshold was made at Shanxi Medical University and Taiyuan University of Technology. Two bipolar stainless steel stimulating electrodes and an electrode connector （diameter 1.2 ram） were made at Taiyuan University of Technology. METHODS： This study was performed in the laboratory of Research Institute of the Epilepsy of Shanxi Medical University between December 2005 and August 2006. The threshold of localized seizures was measured by performing direct cortical stimulation in rats under anesthesia. After 1 week of post-operative recovery, electric stimulation was started with three different kinds of stimulation. Seizure activity was induced by a ramp-shaped single train of biphasic pulses （50 Hz, total pulse duration of 2 ms, increasing from 0 to 2 000μ A in 15 seconds）. The threshold of localized seizures （TLS） has been defined as the minimum current intensity necessary to provoke convulsion of the forelimbs and/or facial muscles. Up to the TLS, if stimulation continued, the current intensity necessary to provoke the generalized seizures is called the threshold of generalized seizures （TGS）. If stimulation is continued for about 2 seconds when the TGS is reached, rats still showed generalized clonic activity after stimulation ceased. When seizures stopped, a short period of immobility can be observed. The current intensity is called the threshold of prolonged seizures （TPS）. The rats in the strong current group were stimulated up to the current level required to reach the TPS. In the course of stimulation, first, the TLS was recorded, then the TGS, and finally the TPS. The stimulation interval in one session was 10 minutes, repeated twice daily. The rats in the weak current group were only stimulated up to the current levels required to reach the TGS; first, the TLS was recorded and then the TGS was measured at the same time as the strong current group. Control animals were also equipped with a full electrode set and placed in the same conditions, but no stimulation took place, only electroencephalogram （EEG） recording at the same times as the experimental groups. MAIN OUTCOME MEASURES： ① Stimulation of the two experimental groups lasted for 11 weeks and then observation of their behavior and electroencephalogram recording continued for 4 weeks. The control group was also observed over a total of 15 weeks. ② Observing neuronal damage/loss in the hippocampus with a light microscope using a 250x visual field. RESULTS： All 36 Wistar rats were included in the final analysis. At the beginning of the experiment, the convulsive thresholds were all above 1 100 μA, although there were significant individual variations among rats of the same group. Those thresholds quickly declined during the initial 4 weeks of repetitive electrical stimulation. The convulsive thresholds approached a constant level in the 10^th week after commencement of stimulation. There were no significant changes in thresholds when stimulations lasted longer; the convulsive thresholds and the variations in rats of the same group were significantly lower than at the beginning of the trial （P 〈 0.01）. An interictal discharge was also recorded in the 3^rd week in the strong current group, and in the 8th week in the weak current group; these discharges were concomitant with neuronal damage and loss in the hippocampus. There was no abnormality observed in the control group. CONCLUSION： These findings indicated that the convulsion threshold in the brain should be divided into two stages： a physiological convulsive threshold and a pathological convulsive threshold （epileptic threshold） The epileptic threshold is created by pathologically acquired factors, which give rise to brain damage. The increase in the intensity of these pathologically acquired factors led to aggravation of damage.

AgAuPd/meso-Co_3O_4: High-performance catalysts for methanol oxidation

The meso-Co3O4 and AgxAuyPd/meso-Co3O4 catalysts were prepared using the KIT-6-templating and polyvinyl alcohol-protected NaBH4 reduction methods,respectively.Various techniques were used to characterize physicochemical properties of these materials.Catalytic performance of the samples was evaluated for methanol combustion.The cubically crystallized Co3O4 support displayed a three-dimensionally ordered mesoporous structure.The supported noble metal nanoparticles(NPs)possessed a surface area of 115.125 m^2/g,with the noble NPs(average size=2.8.4.5 nm)being uniformly dispersed on the surface of meso-Co3O4.Among all of the samples,0.68 wt%Ag0.75Au1.14Pd/meso-Co3O4 showed the highest catalytic activity(T50%=100℃and T90%=112℃at a space velocity of 80000 mL(g^–1 h^–1).The partial deactivation of the 0.68 wt%Ag0.75Au1.14Pd/meso-Co3O4 sample due to water vapor or carbon dioxide introduction was reversible.It is concluded that the good catalytic performance of 0.68 wt%Ag0.75Au1.14Pd/meso-Co3O4 was associated with its highly dispersed Ag0.75Au1.14Pd alloy NPs,high adsorbed oxygen species concentration,good low-temperature reducibility,and strong interaction between Ag0.75Au1.14Pd alloy NPs and meso-Co3O4.

Cavity-induced ATS effect on a superconducting Xmon qubit

We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artificial atom. When driving the cavity to a coherent state, the probe spectrum shows energy level splitting induced by the quantized electromagnetic field in the cavity. This splitting size is related to the coupling strength between the cavity and the artificial atom and, thus, is fixed after the sample is fabricated. This is in contrast to the classical Autler-Townes splitting of a three-level system in which the splitting is proportional to the driving amplitude, which can be continuously changed. Our experiment results show the difference between the classical microwave driving field and the quantum field of the cavity.

Research on Variable Structure and Adaptive Control for Strap-on Rocket

Considering the increase of structural disturbance caused by large thrust misalignment and lack of synchronism after installation of the solid booster on the rock,as well as the increase of external disturbance resulting from the installation of the configuration and tail,while also considering the parameter uncertainties,parameter perturbations,unmodeled dynamics and coupling between channels during modeling,this paper proposes the design method for the adaptive control of sliding mode variable structure,based on the model reference. The paper firstly establishes the attitude dynamics model for the solid strap-on launch vehicle; then proposes the design method for the adaptive control of the sliding mode variable structure based on the model reference,implements the design of attitude control system for the three channels respectively,and uses the Lyapunov function to prove the global asymptotic stability; and finally verifies,through numerical simulation,that the control method proposed in this paper can guarantee the attitude stability of rockets in the primary flight phase.

三维叠层DRAM封装中硅通孔开路缺陷的模拟(英文)

采用硅通孔(TSV)技术的三维堆叠封装,是一种很有前途的解决方案,可提供微处理器低延迟,高带宽的DRAM通道。然而,在3D DRAM电路中,大量的TSV互连结构,很容易产生开路缺陷和耦合噪声,从而导致了新的测试挑战。通过大量的模拟研究,本文模拟了在三维DRAM电路的字线与位线中出现的TSV开路缺陷的故障行为,它作为有效测试和诊断这种缺陷方法的第一步。

Pd Pt VO_(x)/CeO_(2)-ZrO_(2):Highly efficient catalysts with good sulfur dioxide-poisoning reversibility for the oxidative removal of ethylbenzene

The PdPtVO_(x)/CeO_(2)-ZrO_(2)(PdPtVO_(x)/CZO)catalysts were obtained by using different approaches,and their physical and chemical properties were determined by various techniques.Catalytic activities of these materials in the presence of H_(2)O or SO_(2)were evaluated for the oxidation of ethylbenzene(EB).The PdPtVO_(x)/CZO sample exhibited high catalytic activity,good hydrothermal stability,and reversible sulfur dioxide-poisoning performance,over which the specific reaction rate at 160℃,turnover frequency at 160℃(TOF_(Pd or Pt)),and apparent activation energy were 72.6 mmol/(g_(Pt)·sec)or 124.2 mmol/(g_(Pd)·sec),14.2 sec^(-1)(TOF_(Pt))or 13.1 sec^(-1)(TOF_(Pd)),and 58 k J/mol,respectively.The large EB adsorption capacity,good reducibility,and strong acidity contributed to the good catalytic performance of PdPtVO_(x)/CZO.Catalytic activity of PdPtVO_(x)/CZO decreased when 50 ppm SO_(2)or(1.0 vol.%H_(2)O+50 ppm SO_(2))was added to the feedstock,but was gradually restored to its initial level after the SO_(2)was cut off.The good reversible sulfur dioxide-resistant performance of PdPtVO_(x)/CZO was associated with the facts:(i)the introduction of SO_(2)leads to an increase in surface acidity;(ii)V can adsorb and activate SO_(2),thus accelerating formation of the SO_(x)^(2-)(x=3 or 4)species at the V and CZO sites,weakening the adsorption of sulfur species at the PdPt active sites,and hence protecting the PdPt active sites to be not poisoned by SO_(2).EB oxidation over PdPtVO_(x)/CZO might take place via the route of EB→styrene→phenyl methyl ketone→benzaldehyde→benzoic acid→maleic anhydride→CO_(2)and H_(2)O.

Understanding the global cancer statistics 2022:growing cancer burden

The International Agency for Research on Cancer(IARC)established in 1965 as the cancer agency of the World Health Organization,focuses on cancer research and dedicates to developing strategies for cancer control globally.On February 1,2024,IARC unveiled the latest global cancer burden estimates.

氧化石墨烯(GO)及复合物制备及其对汞吸附特性的研究

以石墨粉(G)为原料,通过化学方法制备了氧化石墨烯(GO)、纳米Fe_3O_4负载石墨烯复合材料(MGO)、纳米Ag颗粒修饰磁性氧化石墨烯(GO-Ag/MGO-Ag)四种吸附材料,对材料进行了表征并考察了氧化石墨烯及其复合物对烟气中汞的吸附作用。研究表明四种石墨烯基吸附剂可被成功合成和表征;GO在100-150℃时对Hg^0表现出优异的吸附性能,Ag-NPs修饰GO能有效提升吸附剂对汞的吸附能力,MGO-Ag复合吸附剂对汞的吸附能力最佳;MGOAg在150~200℃时表现出优异的汞吸附能力,在反复循环之后吸附性能几乎不变;以MGO-Ag为代表的可再生磁性石墨烯基复合吸附剂在中低温条件下对Hg^0具有优异的吸附性能,且能有效与飞灰进行分离,具有良好的工业应用前景。

Rare earth oxides and their supported noble metals in application of environmental catalysis

Volatile organic compounds(VOCs),methane,carbon monoxide,soot,automotive exhaust,and nitrogen oxides are harmful to the atmosphere and human health.It is urgent to strictly control their emissions.Heterogeneous catalysis is an effective pathway for the removal of these pollutants,and the critical issue is the development of novel and high-performance catalysts.In this review,we briefly summarize the preparation methods,physicochemical properties,catalytic activities,and related reaction mechanisms for the above pollutants removal of the rare earth oxides,mixed rare earth oxide,rare earth oxidesupported noble metal,and mixed rare earth oxide-supported noble metal catalysts that have been investigated by our group and other researchers.It was found that catalytic performance was associated with the factors,such as specific surface area,pore structure,particle size and dispersion,adsorbed oxygen species concentration,reducibility,reactant activation ability or interaction between metal nanoparticles and support.Furthermore,we also envision the development trend of such a topic in future work.

Preparation of hexagonal ultrathin WO3 nano-ribbons and their electrochemical performance as an anode material in lithium ion batteries

Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] direction, and the main exposed facet is the （720） crystal plane. The HUWNRs exhibit good electrochemical performance as an anode material in lithium ion batteries because of their unique structure. It is believed that these unique materials may be applied in many fields.

PdAg bimetallic electrocatalyst for highly selective reduction of CO2 with low COOH^* formation energy and facile CO desorption

For electrocatalytic reduction of CO2 to CO,the stabilization of intermediate COOH^* and the desorption of CO^* are two key steps.Pd can easily stabilize COOH^*,whereas the strong CO^* binding to Pd surface results in severe poisoning,thus lowering catalytic activity and stability for CO2 reduction.On Ag surface,CO^* desorbs readily,while COOH^* requires a relatively high formation energy,leading to a high overpotential.In light of the above issues,we successfully designed the PdAg bimetallic catalyst to circumvent the drawbacks of sole Pd and Ag.The PdAg catalyst with Ag-terminated surface not only shows a much lower overpotential(-0.55 V with CO current density of 1 mA/cm^2)than Ag(−0.76 V),but also delivers a CO/H2 ratio 18 times as high as that for Pd at the potential of-0.75 V vs.RHE.The issue of CO poisoning is significantly alleviated on Ag-terminated PdAg surface,with the stability well retained after 4h electrolysis at-0.75 V vs.RHE.Density functional theory(DFT)calculations reveal that the Ag-terminated PdAg surface features a lowered formation energy for COOH^* and weakened adsorption for CO^*,which both contribute to the enhanced performance for CO2 reduction.

Influence of post-heat treatment on the microstructure and mechanical properties of Al-Cu-Mg-Zr alloy manufactured by selective laser melting

The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening,arising from high cooling rate in SLM,is underutilized.In this work,compared with the normal T6 heat treatment,a novel simple direct aging regime was proposed to maintain the grain-boundary strengthening and to utilize the precipitation strengthening of secondary AlZr.It was found that a heterogeneous grain structure,which consisted of ultrafine equiaxed(~0.82μm)and columnar(~1.80μm)grains at the bottom and top of molten pool,respectively,was formed in the SLM processed sample.After direct aging(DA),the ultrafine grains were maintained and a mass of spherical coherent L1-AlZr particles with a mean radius of approximately1.15 nm was precipitated.In contrast,after solution treatment and aging(STA),a significant grain coarsening occurred in the equiaxed grain region.Meanwhile,the coarsening L1-AlZr particles,nano-sized S phases and GPB zones were detected in the STA sample.This subsequently induced that the yield strength of the DA sample(~435 MPa)was higher than that of the STA sample(~402 MPa)owing to the grain boundary strengthening and precipitation strengthening.Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6 alloy(~393 MPa).Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6alloy(~393 MPa).

Concurrent catalytic removal of typical volatile organic compound mixtures over Au-Pd/α-MnO2 nanotubes

α-MnO2 nanotubes and their supported Au-Pd alloy nanocatalysts were prepared using hydrothermal and polyvinyl alcohol-protected reduction methods, respectively. Their catalytic activity for the oxidation of toluene/m-xylene, acetone/ethyl acetate, acetone/m-xylene and ethyl acetate/m-xylene mixtures was evaluated. It was found that the interaction between Au-Pd alloy nanoparticles and α-MnO2 nanotubes significantly improved the reactivity of lattice oxygen, and the 0.91 wt.% Au0.48 Pd/α-MnO2 nanotube catalyst outperformed the α-MnO2 nanotube catalyst in the oxidation of toluene, m-xylene, ethyl acetate and acetone. Over the0.91 wt.% Au0.48 Pd/α-MnO2 nanotube catalyst,（i） toluene oxidation was greatly inhibited in the toluene/m-xylene mixture, while m-xylene oxidation was not influenced;（ii） acetone and ethyl acetate oxidation suffered a minor impact in the acetone/ethyl acetate mixture; and（iii） m-xylene oxidation was enhanced whereas the oxidation of the oxygenated VOCs（volatile organic compounds） was suppressed in the acetone/m-xylene or ethyl acetate/m-xylene mixtures. The competitive adsorption of these typical VOCs on the catalyst surface induced an inhibitive effect on their oxidation, and increasing the temperature favored the oxidation of the VOCs. The mixed VOCs could be completely oxidized into CO2 and H2 O below 320°C at a space velocity of 40,000 m L/（g·hr）. The 0.91 wt.% Au0.48 Pd/α-MnO2 nanotube catalyst exhibited high catalytic stability as well as good tolerance to water vapor and CO2 in the oxidation of the VOC mixtures. Thus, the α-MnO2 nanotube-supported noble metal alloy catalysts hold promise for the efficient elimination of VOC mixtures.

Hydrothermal fabrication and visible-light-driven photocatalytic properties of bismuth vanadate with multiple morphologies and/or porous structures for Methyl Orange degradation

Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly（vinyl pyrrolidone） （PVP） and urea （pH = 2） and at 160°C with NaHCO3 （pH = 7 and 8）, respectively. The PVP-derived BiVO4 showed much higher surface areas （5.0-8.4 m2/g） and narrower bandgap energies （2.45-2.49 eV）. The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.

Porous FeO_x/BiVO_(4-δ)S_(0.08): Highly efcient photocatalysts for the degradation of Methylene Blue under visible-light illumination

Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide （y wt.% FeOx/BiVO4-δS0.08, y = 0.06, 0.76, and 1.40） photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-δS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m^2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi^5＋, Bi^3＋, V^5＋, V^3＋, Fe^3＋, and Fe^2＋ species in y wt.% FeOx/BiVO4-δS0.08. The 1.40 wt.% FeOx/BiVO4-δS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower baudgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-δS0.08.

Au-Pd/mesoporous Fe_2O_3:Highly active photocatalysts for the visible-light-driven degradation of acetone

Three-dimensionally ordered mesoporous Fe2O3（meso-Fe2O3） and its supported Au, Pd,and Au-Pd alloy（xA uP dy/meso-Fe2O3; x = 0.08–0.72 wt.%; Pd/Au molar ratio（y） = 1.48–1.85）photocatalysts have been prepared via the KIT-6-templating and polyvinyl alcohol-protected reduction routes, respectively. Physical properties of the samples were characterized, and their photocatalytic activities were evaluated for the photocatalytic oxidation of acetone in the presence of a small amount of H2O2 under visible-light illumination. It was found that the meso-Fe2O3 was rhombohedral in crystal structure. The as-obtained samples displayed a high surface area of 111.0–140.8 m^2/g and a bandgap energy of 1.98–2.12 eV. The Au, Pd and/or Au–Pd alloy nanoparticles（NPs） with a size of 3–4 nm were uniformly dispersed on the surface of the meso-Fe2O3 support. The 0.72 wt.% AuP d1.48/meso-Fe2O3 sample performed the best in the presence of 0.06 mol/L H2O2 aqueous solution, showing a 100% acetone conversion within4 hr of visible-light illumination. It was concluded that the good performance of 0.72 wt.%AuPd（1.48）/meso-Fe2O3 for photocatalytic acetone oxidation was associated with its ordered mesoporous structure, high adsorbed oxygen species concentration, plasmonic resonance effect between AuPd（1.48） NPs and meso-Fe2O3, and effective separation of the photogenerated charge carriers. In addition, the introduction of H2O2 and the involvement of the photo-Fenton process also played important roles in enhancing the photocatalytic activity of 0.72 wt.%AuPd（1.48）/meso-Fe2O3.

Pd/silicalite-1: An highly active catalyst for the oxidative removal of toluene

Catalytic combustion is thought as an efficient and economic pathway to remove volatile organic compounds, and its critical issue is the development of high-performance catalytic materials. In this work, we used the in situ synthesis method to prepare the silicalite-1(S-1)-supported Pd nanoparticles(NPs). It is found that the as-prepared catalysts displayed a hexagonal prism morphology and a surface area of 390-440 m^(2)/g. The sample(0.28Pd/S-1-H)derived after reduction at 500°C in 10 vol% H_(2)showed the best catalytic activity for toluene combustion(T50%= 180℃ and T90%= 189℃ at a space velocity of 40,000 m L/(g·hr), turnover frequency(TOFPd) at 160℃ = 3.46 × 10^(-3)sec^(-1), and specific reaction rate at 160℃ = 63.8μmol/(gPd·sec)), with the apparent activation energy(41 k J/mol) obtained over the bestperforming 0.28Pd/S-1-H sample being much lower than those(51-70 k J/mol) obtained over the other samples(0.28Pd/S-1-A derived from calcination at 500℃ in air, 0.26Pd/S-1-im derived from the impregnation route, and 0.27Pd/ZSM-5-H prepared after reduction at 500℃ in 10 vol% H_(2)). Furthermore, the 0.28Pd/S-1-H sample possessed good thermal stability and its partial deactivation due to CO_(2) or H_(2)O introduction was reversible, but SO_(2) addition resulted in an irreversible deactivation. The possible pathways of toluene oxidation over 0.28Pd/S-1-H was toluene → p-methylbenzoquinone → maleic anhydride, benzoic acid, benzaldehyde → carbon dioxide and water. We conclude that the good dispersion of Pd NPs, high adsorption oxygen species concentration, large toluene adsorption capacity, strong acidity,and more Pd~0 species were responsible for the good catalytic performance of 0.28Pd/S-1-H.