Thermal stable Pt clusters anchored by K/TiO_(2)—Al_(2)O_(3)for efficient cycloalkane dehydrogenation

Catalytic dehydrogenation of cycloalkanes is considered a valuable endothermic process for alleviating the thermal barrier issue of hypersonic vehicles.However,conventional Pt-based catalysts often face the severe problem of metal sintering under high-temperature conditions.Herein,we develop an efficient K_(2)CO_(3)-modified Pt/TiO_(2)—Al_(2)O_(3)(K—Pt/TA)for cycloalkane dehydrogenation.The optimized K—Pt/TA showed a high specific activity above 27.9 mol·mol^(-1)·s^(-1)(H_(2)/Pt),with toluene selectivity above 90.0%at 600℃with a high weight hourly space velocity of 266.4 h^(-1).The introduction of alkali metal ions could generate titanate layers after high-temperature hydrogen reduction treatment,which promotes the generation of oxygen vacancy defects to anchored Pt clusters.In addition,the titanate layers could weaken the surface acidity of catalysts and inhibit side reactions,including pyrolysis,polymerization,and isomerization reactions.Thus,this work provides a modification method to develop efficient and stable dehydrogenation catalysts under high-temperature conditions.

Research and Design of Consistent Project Cases for the Software Engineering Course Group

In order to enhance the abilities of practical innovation and solving complex engineering problems of students in the engineering context,we design a course cluster teaching model based on a unified enterprise-level project case.The program divides the knowledge points required by the project into the corresponding courses,and divides their realization into the practical teaching cases,so as to realize the design of teaching practice cases embodied in the unified project framework.This model allows students to practice projects based on the unified project background while learning knowledge from different courses.It not only allows students to learn abstract,fragmented,and difficult-to-understand knowledge systems thoroughly,but also integrates the knowledge into the practice of the enterprise-level project development,helping students experience the value of knowledge in complex engineering projects and thus improving their ability to solve complex engineering problems while learning theoretical knowledge.

Effects of porous oxide layer on performance of Pd-based monolithic catalysts for 2-ethylanthraquinone hydrogenation

Pd/oxide/cordierite monolithic catalysts(oxide = Al_2O_3, SiO_2 and SiO_2\\Al_2O_3) were prepared by the impregnation method. The results of ICP, XRD, SEM–EDX, XPS and N_2 adsorption–desorption measurements revealed that the Pd penetration depth increased with increasing the thickness of oxide layer, and the catalysts with Al_2O_3 layers had the larger pore size than those with SiO_2 and SiO_2\\Al_2O_3 layers. Catalytic hydrogenation of 2-ethylanthraquinone(eA Q), a key step of the H_2O_2 production by the anthraquinone process, over the various monolithic catalysts(60 °C, atmosphere pressure) showed that the monolithic catalyst with the moderate thickness of Al_2O_3 layer(about 6 μm) exhibited the highest conversion of e AQ(99.1%) and hydrogenation efficiency(10.0 g·L^(-1)). This could be ascribed to the suitable Pd penetration depth and the larger pore size, which provides a balance between the distribution of Pd and accessibility of active sites by the reactants.

Reliability evaluation on sense-switch p-channel flash

In this paper,the reliability of sense-switch p-channel flash is evaluated extensively.The endurance result indicates that the p-channel flash could be programmed and erased for more than 10000 cycles;the room temperature read stress shows negligible influence on the p-channel flash cell;high temperature data retention at 150℃ is extrapolated to be about 5 years and 53 years corresponding to 30% and 40% degradation in the drive current,respectively.Moreover,the electrical parameters of the p-channel flash at different operation temperature are found to be less affected.All the results above indicate that the sense-switch p-channel flash is suitable to be used as the configuration cell in flash-based FPGA.

Direct synthesis of hydrogen peroxide over Pd nanoparticles embedded between HZSM-5 nanosheets layers

Direct synthesis of hydrogen peroxide(DSHP)was studied over Pd loaded on HZSM-5 nanosheets(Pd/ZN).Pd nanoparticles with average size of ca.4.3 nm were introduced into the adjacent nanosheet layers(thickness of ca.2.9 nm)by impregnation method.Pd/ZN with theoretical Si/Al molar ratio of 25 showed the highest selectivity for H2O2 among the prepared catalysts,together with highest formation rate of H2O2(38.0 mmol·(g cat)^-1·h^-1),1.9 times than that of Pd supported on conventional HZSM-5 zeolite(Pd/CZ-50).Better catalytic performance of nanosheet catalysts was attributed to the promoted Pd dispersion which promoted H2 dissociation,more BrΦnsted acid sites and stronger metal-support interaction which inhibited the dissociation of O-O bond in H2O2.The embedded structure sufficiently protected the Pd nanoparticles by space confinement which restrained the Pd leaching,leading to a better catalytic stability with 90%activity retained after 3 cycles,which was almost 3 times than that of Pd/CZ-50(30.4%activity retained).

Highly dispersible cerium-oxide modified Ni/SBA-15 for steam reforming of bio-mass based JP10

Ni/SBA-15 modified by highly dispersed cerium-oxide was prepared with the aid of sucrose for steam reforming of JP10(C_(10)H(16)).Their characterization showed that addition of appropriate amount ceria led to the formation of highly dispersed CeO_(2)and Ni,and the CeO_(2)covered smaller nickel particles like strawberry seeds to form much more interface between them.Their catalytic activity exhibited higher stability over time on stream of 6.5 h with conversion higher than 95%and higher carbon resistance(mass loss less than 4.5%by TG),which may derive from good properties below:(1)much more interface enhanced cooperation effect and increased turnover frequency at the interface;(2)the stronger interaction between Ni and ceria to suppress sintering by formation of Ni-O-Ce solid solution;(3)the large amount of oxygen vacancies from the formation of Ni-O-Ce solid solution and highly dispersed CeO_(2)to facilitate the water-gas-shift reaction and carbon removal.

Research on eigenstate current control technology of Flashbased FPGA

To solve the Flash-based FPGA in the manufacturing process,the ion implantation process will bring electrons into the floating gate of the P-channel Flash cell so that the Flash switch is in a weak conduction state,resulting in the Flash-based FPGA eigenstate current problem.In this paper,the mechanism of its generation is analyzed,and four methods are used includ-ing ultraviolet light erasing,high-temperature baking,X-ray irradiation,and circuit logic control.A comparison of these four methods can identify the circuit design by using circuit logic to control the path of the power supply that is the most suitable and reliable method to solve the Flash-based FPGA eigenstate current problem.By this method,the power-on current of 3.5 mil-lion Flash-based FPGA can be reduced to less than 0.3 A,and the chip can start normally.The function and performance of the chip can then be further tested and evaluated,which is one of the key technologies for developing Flash-based FPGA.

Controllably tailoring external surface sites of nanosheet HZSM-5 for maximizing light olefins in catalytic cracking of n-decane

A series of triphenylethoxysilane(TPEOS)-modified nanosheet HZSM-5 catalysts(ZN-x,x=4%,8%and16%,mass)were synthesized by chemical liquid deposition to selectively change external acidity distributions.TPEOS modification was found to passivate some external Br?nsted and Lewis acid sites by37.8%,in which Br?nsted acid sites(BAS)were found more easily sacrificed by breaking the surface Al AO bond of bridging hydroxyl groups and forming Si AOASi bonds.The selectivity of ZN-8 catalyst for light olefins(ethylene,propylene and butene)in n-decane catalytic cracking is up to 26%(450℃,WHSV=10.95 h^(-1)),which is ca.78%higher than that of parent one.The better performance was attributed to the appropriate external acid density in ZN-8,which inhibits bimolecular hydrogen transfer reaction of light olefins on the adjacent acid sites,resulting in more olefins,few coke precursors and thus an excellent catalytic stability.

Role of Ni species in ZnO supported on Silicalite-1 for efficient propane dehydrogenation

Propane dehydrogenation(PDH)is one of the most effective technologies to produce propene.Non-noble zinc-based catalysts have paid increasing attention because of low cost and nontoxic,compared with industrial Pt and Cr-based catalysts.However,they often suffer from limited catalytic activity and poor stability.Here,we introduced moderate Ni into ZnO supported Silicalite-1 zeolite to increase catalytic activity and stability simultaneously.Zn^(2+) was the definite active site and NiZn alloy facilitated the sluggish H recombination into H_(2)via reverse spillover.Furthermore,the introduction of Ni increased Lewis acid strength caused by electron transfer from ZnO to NiZn alloy,contributing to improved stability.For resulted 0.5 NiZn/S-1,propene formation rate was 0.18 mol C_(3)H_(6)·(g Zn)^(-1)·h^(-1) at 550℃,which was above 1.5 times higher than that over Zn/S-1 without Ni.Under stability test,the deactivation of0.5 NiZn/S-1 was 0.019 h^(-1),which was only 1/10 of that over Zn/S-1.

Exploration and Practice of Student Engineering Competency Training in University-Industry Collaboration Model

Engineering competency is a basic and important quality of being an engineer,but it is one of the weak points in today’s higher engineering education.Taking industrial development needs as the goal of personnel training and focusing on the cultivation of engineering competency,the authors design an integrated practical teaching system,which is based on the requirements for engineering and technical professionals and the characteristics of Qingdao University of Science and Technology(QUST).The system adopts a“project driven”teaching method and a“swimming poolTM”training mode and establishes a teaching,administration,feedback and evaluation platform consistent with the implementation of this practical teaching mode,so as to ensure the quality of engineering and technical professionals training in an in-depth university-industry collaboration mode.

Egg shell waste as an activation agent for the manufacture of porous carbon

Egg shell waste was used as an activation agent directly for the manufacture of a biomass-derived porous carbon,which possessed a surface area of 626 m2·g-1 and was rich in nitrogen,sulfur and oxygen functionalities.The activation mechanism was proposed,and the carbon showed its potential to act as an adsorbent for the adsorptive removal of various contaminants from both aqueous and non-aqueous solutions,possessing maximum adsorption capacities of 195.9,185.1,125.5 and 44.6 mg·g-1 for sulfamethoxazole,methyl orange,diclofenac sodium and dibenzothiophene,respectively.Through the utilization of egg shell waste as a sustainable activation agent,this work may help to make the widely applied biomass-derived porous carbons more economical and ecological.

Editorial for special issue on Carbon-neutrality Chemical Engineering

Climate change and emissions of greenhouse gases are becoming a threat to the earth environment,human lives and global health now.All of us,whether as individuals,commercial enterprises,institutions,or governments,share a collective responsibility to reduce and ultimately neutralize the greenhouse gas emissions by mid-to-late century.Carbon neutral goal will bring extensive and systematic changes in global energy consumptions,economic and social activities,and also offers a huge opportunity for the global chemical industries and chemical engineers to resolve this challenging global issue.

Design and verification of an FPGA programmable logic element based on Sense-Switch pFLASH

This paper proposes a kind of programmable logic element(PLE)based on Sense-Switch pFLASH technology.By programming Sense-Switch pFLASH,all three-bit look-up table(LUT3)functions,partial four-bit look-up table(LUT4)functions,latch functions,and d flip flop(DFF)with enable and reset functions can be realized.Because PLE uses a choice of operational logic(COOL)approach for the operation of logic functions,it allows any logic circuit to be implemented at any ratio of combinatorial logic to register.This intrinsic property makes it close to the basic application specific integrated circuit(ASIC)cell in terms of fine granularity,thus allowing ASIC-like cell-based mappers to apply all their optimization potential.By measuring Sense-Switch pFLASH and PLE circuits,the results show that the“on”state driving current of the Sense-Switch pFLASH is about 245.52μA,and that the“off”state leakage current is about 0.1 pA.The programmable function of PLE works normally.The delay of the typical combinatorial logic operation AND3 is 0.69 ns,and the delay of the sequential logic operation DFF is 0.65 ns,both of which meet the requirements of the design technical index.

Insight into the adsorption behavior and mechanism of trace impurities from H_(2)O_(2) solution on functionalized zirconia by tuning the structure of amino groups

Primary,secondary and tertiary amino-functionalized zirconia(ZrO_(2)-NH_(2),ZrO_(2)-NH and ZrO_(2)-N)was synthesized by the postgrafting method for the adsorption removal of typical metallic ions,phosphate and total oxidizable carbon from a real H_(2)O_(2) solution.ZrO_(2)-NH_(2),ZrO_(2)-NH and ZrO_(2)-N exhibited similar pore sizes and sequentially increased zeta potentials.The adsorption results of single and binary simulated solutions showed that the removal efficiency increased in the order of Fe^(3+)>Al^(3+)>Ca^(2+)>Na^(+).There is competitive adsorption between metallic ions,and Fe^(3+) has an advantage over the other metals,with a removal efficiency of 90.7%.The coexisting phosphate could promote the adsorption of metallic ions,while total oxidizable carbon had no effect on adsorption.The adsorption results of the real H_(2)O_(2)solution showed that ZrO_(2)-NH_(2) exhibited the best adsorption affinity for metallic ions,as did phosphate and total oxidizable carbon,with a total adsorption capacity of 120.9 mg·g_(-1).Density functional theory calculations revealed that the adsorption process of metallic ions involves electron transfer from N atoms to metals and the formation of N-metal bonds.

Direct synthesis of hydrogen peroxide on Pd nanosheets with edge decorated by Au nanoparticles

Direct synthesis of hydrogen peroxide from hydrogen and oxide(DSHP)is considered as a green pathway for H2O2 production because of the simple reaction route and 100%theoretical atom efficiency.Here,1.5 wt%Pd and 0.5 wt%Au were loaded on HZSM-5 nanosheets through sequential isovolumetric impregnation.TEM images and CO-TPD curves showed that Pd nanosheets were successfully synthesized between HZSM-5 nanosheets under zeolite confinement effect,and Au particles were loaded on the edge of Pd nanosheets and formed a structure that Pd nanosheets with edge decorated by Au nanoparticles(Au–Pd/ZN).The results showed that the selectivity for H2O2 could be reached around 60%in a 30 min reaction and the initial H2O2 productivity could reach 338.5 mmol gcat1 h1 on the Au–Pd/ZN catalyst.The enhanced selectivity and productivity could be related with high content of terrace sites and Au particles on the step sites of bimetallic nanosheets,in which both the terrace sites and the step sites replaced by Au particles showed higher dissociation activation energy for breaking the O–O bond than traditional step sites on Pd particles,inhibited the by-product reactions(2H2O2→2H2OþO2,2H2þO2→2H2O).