Structure design and electrochemical properties of carbon-based single atom catalysts in energy catalysis:A review

Single atom catalysts(SACs) possessing regulated electronic structure, high atom utilization, and superior catalytic efficiency have been studied in almost all fields in recent years. Carbon-based supporting SACs are becoming popular materials because of their low cost, high electron conductivity, and controllable surface property. At the stage of catalysts preparation, the rational design of active sites is necessary for the substantial improvement of activity of catalysts. To date, the reported design strategies are mainly about synthesis mechanism and synthetic method. The level of understanding of design strategies of carbon-based single atom catalysts is requiring deep to be paved. The design strategies about manufacturing defects and coordination modulation of catalysts are presented. The design strategies are easy to carry out in the process of drawing up preparation routes. The components of carbon-based SACs can be divided into two parts: active site and carbon skeleton. In this review, the manufacture of defects and coordination modulation of two parts are introduced, respectively. The structure features and design strategies from the active sites and carbon skeletons to the overall catalysts are deeply discussed.Then, the structural design of different nano-carbon SACs is introduced systematically. The characterization of active site and carbon skeleton and the detailed mechanism of reaction process are summarized and analyzed. Next, the applications in the field of electrocatalysis for oxygen conversion and hydrogen conversion are illustrated. The relationships between the superior performance and the structure of active sites or carbon skeletons are discussed. Finally, the conclusion of this review and prospects on the abundant space for further promotion in broader fields are depicted. This review highlights the design and preparation thoughts from the parts to the whole. The detailed and systematic discussion will provide useful guidance for design of SACs for readers.

Promoting grain production through high-standard farmland construction:Evidence in China

Food security is a strategic priority for a country’s economic development.In China,high-standard farmland construction(HSFC)is an important initiative to stabilize grain production and increase grain production capacity.Based on panel data from 31 sample provinces,autonomous regions,and municipalities in China from 2005–2017,this study explored the impact of HSFC on grain yield using the difference-in-differences(DID)method.The results showed that HSFC significantly increased total grain production,which is robust to various checks.HSFC increased grain yield through three potential mechanisms.First,it could increase the grain replanting index.Second,it could effectively reduce yield loss due to droughts and floods.Last,HSFC could strengthen the cultivated land by renovating the low-and medium-yielding fields.Heterogeneity analysis found that the HSFC farmland showed a significant increase in grain yield only in the main grain-producing areas and balanced areas.In addition,HSFC significantly increased the yields of rice,wheat,and maize while leading to a reduction in soybean yields.The findings suggest the government should continue to promote HSFC,improve construction standards,and strictly control the“non-agriculturalization”and“non-coordination”of farmland to increase grain production further.At the same time,market mechanisms should be used to incentivize soybean farming,improve returns and stabilize soybean yields.

For more and purer hydrogen-the progress and challenges in water gas shift reaction

The water gas shift(WGS) reaction is a standard reaction that is widely used in industrial hydrogen production and removal of carbon monoxide. The improved catalytic performance of WGS reaction also contributes to ammonia synthesis and other reactions. Advanced catalysts have been developed for both high and low-temperature reactions and are widely used in industry. In recent years, supported metal nanoparticle catalysts have been researched due to their high metal utilization. Low-temperature catalysts have shown promising results, including high selectivity, high shift rates, and higher activity potential. Additionally, significant progress has been made in removing trace CO through the redox reaction in electrolytic cell. This paper reviews the development of WGS reaction catalysts, including the reaction mechanism, catalyst design, and innovative research methods. The catalyst plays a crucial role in the WGS reaction, and this paper provides an instant of catalyst design under different conditions. The progress of catalysts is closely related to the development of advanced characterization techniques.Furthermore, modifying the catalyst surface to enhance activity and significantly increase reaction kinetics is a current research direction. This review goals to stimulate a better understanding of catalyst design, performance optimization, and driving mechanisms, leading to further progress in this field.

Engineering Vacancy-Atom Ensembles to Boost Catalytic Activity toward Hydrogen Evolution

The dissociation of water is the rate-determining step of several energy-relating reactions due to high energy barrier in homolysis of H-O bond.Herein,engineering vacancy-atom ensembles via injecting oxygen vacancy(V O)into single facet-exposed TiO_(2)-Pd catalyst to form V_(O)-Pd ensemble is proposed and implemented.The outstanding activity of as-prepared catalyst,1.5-PdTV_(O),toward water dissociation is established with a turnover frequency of 240 min^(−1) in ammonia borane hydrolysis at 298 K.Density functional theory simulation suggests that the V_(O)-Pd ensemble is responsible for the high intrinsic catalytic activity.Water molecules tend to be dissociated on V_(O) sites and ammonia borane molecules on Pd atoms.Those H atoms from water dissociation on V_(O) combine with H atoms from ammonia borane on Pd atoms to generate H_(2).This insights into engineering vacancy-atom ensembles catalysis provide a new avenue to design catalytic materials for important energy chemical reactions.

Side Effects of Gamifying Environmental Education Activities in Chinese Kindergartens

Environmental education is an effective approach to addressing environmental issues,and incorporating environmental education into kindergarten through gamified activities aligns with the concept of gamifying teaching and provides the optimal pathway for implementing environmental education.The purpose of this study is to investigate the specific processes involved in determining the objectives,themes,and content of gamified environmental education activities,as well as the organization,implementation,and evaluation of these activities in kindergarten settings.Five classes from Class G in Xining City Kindergarten were selected as the observational subjects for this study.Interviews were conducted with the teaching staff and the head of the kindergarten.The data obtained from observations and interviews served as the primary data for this research.The results indicate that the activity objectives formulated by teachers lack scientific basis and operability,with limited incorporation of gaming elements.The activity themes and content are narrow in scope and primarily determined by teachers and kindergarten administrators.The organization and implementation of activities often neglect the playful experiences of children,and activity evaluation is not given sufficient attention.

Polar O-Co-P Surface for Bimolecular Activation in Catalytic Hydrogen Generation

Boron hydrides release an abundant amount of hydrogen in the presence of a suitable catalyst.Accelerating bimolecular activation kinetics is the key to designing cost-effective catalysts for borohydride hydrolysis.In this study,the bimolecular activation of a polar O-Co-P site demonstrated superior hydrogen-generation kinetics(turnover frequency,TOF=37 min−1,298 K)and low activation energy(41.0 kJ mol^(−1))close to that of noble-metal-based catalysts.Through a combination of experiments and theoretical calculations,it was revealed that the activated dangling oxygen atom in the Co–O precursor effectively replaced via surface-phosphorization because of strong electronic interactions between the dangling oxygen and P atoms.This substitution modulated the local coordination environment and electronegativity around the surface Co sites and formed a new polar O-Co-P active site for optimizing the activation kinetics of ammonia borane and water.This strategy based on bimolecular activation may create new avenues in the field of catalysis.

A CuO/TiO_(2)Heterojunction Based CO Sensor with High Response and Selectivity

The use of heterojunctions is a promising solution to the problem of cross-sensitivity in gas sensors.In this work,a carbon monoxide sensor based on the CuO/TiO_(2)heterojunction was designed and fabricated.Due to the good adsorption properties of CuO materials to CO,and the heterojunction interface charge transfer,the CuO/TiO_(2)thin film sensor exhibits high sensitivity to CO at room temperature.The response is as high as 10.8–200 ppm CO,about 10 times its response to H_(2).Interference from H_(2)is greatly reduced by optimizing the structure of the CuO/TiO_(2)heterojunction.This reliable detection of carbon monoxide with excellent discrimination against H_(2)is of great significance for the development of CO gas sensors.

The Summary of the Research on the Compound Braking Strategy of Four Wheel Hub Motor Drive Electric Vehicle

This paper describes in detail three kinds of typical compound braking strategy of wheel motor drive electric vehicle and summarizes the current commonly used strategies based on the three typical strategies developed. In the end, a new compound braking strategy is proposed;that is, we take braking mode classify, ECE regulations and SOC value of the battery as an important reference of braking force that joins the motor braking force, as well as we join the different identification models;according to the different braking modes, the purpose is that we can apply the different braking program.

Interface tuning of Cu+/CuO by zirconia for dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO2 catalyst

An efficient ZrO2-doped Cu/SiO2 catalyst was fabricated through hydrolysis precipitation method(HP)and used to produce ethylene glycol(EG)through dimethyl oxalate(DMO)hydrogenation.The states for zirconia on copper catalyst and roles in DMO hydrogenation were investigated through various characterization tools,including N2 physical adsorption,XRD,H2-TPR,Methyl glycolate-TPD-MS,XPS,XAES as well.Compared with common ammonia evaporation and co-precipitation methods used in catalyst preparation,this HP method is found to effectively suppress the agglomeration and further size growth of copper nanoparticles by enhancing the interactions between copper and zirconia species.More importantly,uniform distribution of ZrO2 dopant is achieved due to the pseudo-homogeneous reactions in the mixing step of catalyst preparation.A proper amount of zirconium dopant helps achieve the desirable proportion of Cu+/(Cu++CuO)for surface copper species,especially promotes the production of Cu+species originated from Cu-ZrO2 species at the interface of copper and zirconia particles.In comparison with Cu+species formed from copper phyllosilicates reduction,the Cu+sites derived from Cu-ZrO2 species show higher adsorption ability of MG,an important intermediate species in ethylene glycol production.These adsorbed MG molecules further react with atomic hydrogen shifted from adjacent metallic copper surface,leading to a higher catalytic behavior.For the EG production via DMO hydrogenation,the turnover frequency(TOF)normalized by CuO species on CuZr/SiO2 catalyst is 1.8 times than that of traditional Cu/SiO2 counterpart.Due to the enhanced synergy effect between Cu+and Cuo active sites,a lower activation energy of ester hydrogenation on this ZrO2-doped Cu/SiO2 catalyst is believed to be responsible for the significant improvement.

超声心动图诊断胎儿单纯肺动脉瓣狭窄的价值

目的探讨超声心动图在诊断胎儿单纯肺动脉瓣狭窄(PVS)中的价值。方法回顾性分析2019年1月至2022年12月在天津市中心妇产科医院超声科和承德医学院附属医院南区超声科产前经超声心动图诊断为单纯PVS的胎儿35例。胎儿心脏超声检查获取四腔心切面、左心室及右心室流出道切面、三血管切面等。测量各心腔横径,观察房室瓣启闭及反流情况。出生的胎儿均于产后24 h内行超声心动图检查,测量肺动脉速度和肺动脉跨瓣压差,评估肺动脉瓣狭窄程度。分析产前和产后超声心动图检查结果,采用Pearson相关分析产前PVS分组(正向组、逆向组)与产后PVS分度(轻、中、重度)之间的相关性。结果35例单纯PVS胎儿引产8例,出生27例。产前动脉导管(DA)正向组15例,逆向组20例,2组病例肺动脉流速、肺动脉狭窄后扩张和三尖瓣反流程度差异具有统计学意义(P<0.05)。肺动脉内径,左、右肺动脉内径,肺动脉瓣开口和右心室横径/左心室横径差异无统计学意义(P>0.05)。27例出生后新生儿期超声心动图检查均证实有不同程度PVS,轻度15例,中度8例,重度4例。产前PVS不同分组与产后PVS不同分度之间具有相关性(Pearson相关系数=0.58,P<0.05),产前正向组病例产后大部分为轻度PVS(12/14,85.71%),逆向组病例产后中度和重度PVS居多(10/13,76.92%)。结论胎儿单纯PVS肺动脉流速快,三尖瓣反流程度重,DA逆灌产后可能中度以上PVS的可能性大,狭窄后扩张是胎儿PVS的一个重要间接征象。胎儿单纯PVS可以在产前进行诊断,超声心动图是诊断胎儿单纯PVS并预估其产后分度的重要手段。

The eff ect of Rhizophagus irregularis on salt stress tolerance of Elaeagnus angustifolia roots

We assessed the eff ects of arbuscular mycorrhizal fungi(AMF)Rhizophagus irregularis inoculation on salt stress tolerance in roots of the drought-tolerant plant Elaeagnus angustifolia.We studied a plant growth index,spore density and hyphal length density of AMF,the Na+contents and ultrastructure of root cells,as well as rhizosphere soil enzyme activities of mycorrhizal and non-mycorrhizal E.angustifolia seedlings under diff erent salt stress.Under salt stress,growth of E.angustifolia with mycorrhizal inoculation was higher than that of non-inoculated treatments.The spore density and hyphal length density decreased signifi cantly under salt stress in rhizosphere soil of mycorrhizal E.angustifolia seedlings(p<0.05).The root cells of E.angustifolia seedlings inoculated with R.irregularis at 300 mmol L−1 salt had more organelles,greater integrity,and lower root Na+contents than those of non-inoculated seedlings.In addition,the results showed notably higher activities of catalase,phosphatase,urease and saccharase in rhizosphere soil of the mycorrhizal seedlings in response to salinity compared to those of the non-mycorrhizal seedlings.Therefore,AMF inoculation could enhance salt stress tolerance in roots of E.angustifolia.

Molecular dynamics study of room temperature ionic liquids with water at mica surface

Water in room temperature ionic liquids(RTILs) could impose significant effects on their interfacial properties at a charged surface. Although the interfaces between RTILs and mica surfaces exhibit rich microstructure, the influence of water content on such interfaces is little understood,in particular, considering the fact that RTILs are always associated with water due to their hygroscopicity. In this work, we studied how different types of RTILs and different amounts of water molecules affect the RTIL-mica interfaces, especially the water distribution at mica surfaces,using molecular dynamics(MD) simulation. MD results showed that(1) there is more water and a thicker water layer adsorbed on the mica surface as the water content increases, and correspondingly the average location of K^+ ions is farther from mica surface;(2) more water accumulated at the interface with the hydrophobic [Emim][TFSI] than in case of the hydrophilic [Emim][BF4] due to the respective RTIL hydrophobicity and ion size. A similar trend was also observed in the hydrogen bonds formed between water molecules. Moreover, the 2D number density map of adsorbed water revealed that the high-density areas of water seem to be related to K^+ ions and silicon/aluminum atoms on mica surface. These results are of great importance to understand the effects of hydrophobicity/hydrophicility of RTIL and water on the interfacial microstructure at electrified surfaces.

Research on the Stability Control Strategy of Four-Wheel Independent Driving Electric Vehicle

In order to research stability of four-wheel independent driving (4WID) electric vehicle, a torque allocation method based on the tire longitudinal forces optimization distribution is adopted. There are two layers in the controller, which includes the upper layer and the lower layer. In the upper layer, according to the demand of the longitudinal force, PID controller is set up to calculate the additional yaw moment created by yaw rate and side-slip angle. In the lower layer, the additional yaw moment is distributed properly to each wheel limited by several constraints. Carsim is used to build up the vehicle model and MATLAB/Simulink is used to build up the control model and both of them are used to simulate jointly. The result of simulation shows that a torque allocation method based on the tire longitudinal forces optimization distribution can ensure the stability of the vehicle.

Oxygen vacancy promoting artificial atom(RuPd)by d-orbital coupling for efficient water dissociation

Rational design of highly active catalysts for breaking hydrogen-oxygen bonds is of great significance in energy chemical reactions involving water.Herein,an efficient strategy for the artificial atom(RuPd)established by d-orbital coupling and adjusted by oxygen vacancy(V_(O))is verified for water dissociation.As an experimental verification,the turnover frequency of RuPd-TiO_(2)-VO(RuPdTVO)catalyst in ammonia borane hydrolysis reaches up to 2750 min^(−1)(26,190 min−1 based on metal dispersion)in the absence of alkali,exceeding the highest active catalysts(Rh-based catalysts).The d-orbital coupling effect between Ru and Pd simulates the outer electronic structure of Rh.Electron transfer from V_(O) to(RuPd)constructs an electron-rich state of active sites that further enhances the ability of the artificial atom to dissociate water.This work provides an effective electronic regulation strategy from V_(O) and artificial atom constructed by d-orbital coupling effect for efficient water dissociation.

Coupling atom ensemble and electron transfer in PdCu for superior catalytic kinetics in hydrogen generation

The design of high-performance catalysts is the key to the efficient utilization of hydrogen energy.In this work,a PdCu nanoalloy was successfully anchored on TiO_(2)encapsulated with carbon to construct a catalyst.Outstanding kinetics of the hydrolysis of ammonia borane(turnover frequency of 279 mol·min^(-1·)mol_(Pd)^(-1))ranking the third place among Pd-based catalysts was achieved in the absence of alkali.Both experimental research and theoretical calculations reveal a lower activation energy of the B-H bond on the PdCu nanoalloy catalyst than that on pristine Pd and a lower activation energy of the O-H bond than that on pristine Cu.The redistribution of d electron and the shift of the d-band center play a critical role in increasing the electron density of Pd and improving the catalytic performances of Pd_(0.1)Cu_(0.9)/TiO_(2)-porous carbon(Pd_(0.1)Cu_(0.9)/T-PC).This work provides novel insights into highly dual-active alloys and sheds light on the mechanism of dual-active sites in promoting borohydride hydrolysis.

Functional customization of two-dimensional materials for photocatalytic activation and conversion of inert small molecules in the air

Air has the advantage of abundance and easy availability,so it is suitable to be used as a synthetic raw material and energy source.However,the triggering of inert small molecules in the air,like O_(2),N2,and CO_(2),is a kinetically complex and energetically challenging multistep reaction.Photocatalysis brings hope for this challenge,but obstacles remain in many aspects.Here,aiming at the key difficulties of the photocatalytic activation and conversion of these three inert small molecules,i.e.,regulating electronic structure,active sites,charge carrier separation and mobility,and reaction energy barrier,we propose the concept of functional customization strategy of ultrathin two-dimensional materials for achieving more efficient activation and better performance,including thickness control,vacancy engineering,doping operation,single-atom site fabrication,and composite construction.The in-depth understanding of the functional customization will provide more profound guidance for designing photocatalysts that specialize in activating and converting inert small molecules.

基于甘油的1,3-丙二醇生物合成的代谢局限及其改造策略

粗甘油是生物柴油生产中的主要副产物,一些微生物可将甘油转化为重要化工原料1,3-丙二醇(1,3-PD),而利用这些微生物野生菌株生物合成1,3-PD会存在一些局限性,如底物抑制、产物抑制等。文中从1,3-丙二醇的甘油生物转化途径与这些局限性出发,总结了生物合成中存在的问题,并针对这些问题提出了一些基于基因敲除或基因过表达等基因工程技术的改造方法,综述了利用基因工程菌生物转化甘油生成1,3-丙二醇的最新研究进展。

基于内源Ⅲ-B型CRISPR-Cas系统构建超嗜热火球菌Pyrococcus yayanosii A1的基因敲降系统

【目的】亚氏火球菌(Pyrococcus yayanosii)A1菌株的最适生长温度为98℃,最适生长压力为5.2×10^(4) Pa,是研究此类严格厌氧、超嗜热和兼性嗜压古菌的环境适应性机制的良好材料。本研究基于P.yayanosii A1基因组中Ⅲ-B型CRISPR-Cas系统,旨在建立可应用于此类古菌的基因表达敲降系统(gene knock-down system)。【方法】人工构建的mini-CRISPR簇,由内源性CRISPR簇Group 1的重复序列(repeats)和待敲降的淀粉酶基因(PYCH_13690)中的原间隔序列(protospacer)组成。将该mini-CRISPR簇插入到具有辛伐他汀抗性的穿梭载体pLMOShhp中,使之转录与目的基因mRNA匹配的crRNA,引导Cmr复合物对其进行切割。【结果】使用高静水压(HHP)诱导型启动子Phhp诱导mini-CRISPR簇表达时,淀粉酶基因的mRNA数量在5.2×10^(4) Pa静水压时下调到原来的67.05%,在1.0×10^(2) Pa静水压时下调为原来的49.69%;而使用组成型启动子Phmtb诱导mini-CRISPR簇表达时,淀粉酶基因的mRNA数量在5.2×10^(4) Pa静水压时下调为原来的58.48%,在1.0×10^(2) Pa静水压时下调为原来的23.97%。使用鲁戈氏碘液显色法对这两类基因表达敲降突变菌株的培养物中残留的淀粉含量进行分析,结果显示突变菌株的淀粉降解能力明显降低。【结论】在P.yayanosii A1中建立了基于内源Ⅲ-B型CRISPR-Cas系统的基因敲降系统,可以用于抑制此类超嗜热嗜压古菌体内基因的表达。

The steady-state level of CDK4 protein ms regulated by antagonistic actions between PAQR4 and SKP2 and involved in tumorigenesis

CDK4 is crucial for Gl-to-S transition of cell cycle. It is well established that ubiquitin-mediated degradations of CDK inhibitors and cycUns are pivotal for the timely and unidirectional progression of cell cycle. However, how CDK4 itself is modulated by ubiquitin-mediated degradation has been elusive. Here we report that the steady-state level of CDK4 is controlled by PAQR4, a member of the progestin and adipoQ receptor family, and SKP2, an E3 ubiquitin ligase. Knockdown of PAQR4 leads to reduction of cell proliferation, accompanied by reduced protein level of CDK4. PAQR4 reduces polyubiquitination and degradation of CDK4. PAQR4 interacts with the C-terminal lobe of CDK4. On the other hand, SKP2 also interacts with the C-terminal lobe of CDK4 and enhances polyubiquitination and degradation of CDK4. importantly, PAQR4 and SKP2 bind to the same region in CDK4, and PAQR4 competes with SKP2 for the binding, thereby abrogating SKP2-mediated ubiquitination of CDK4. Using a two-stage DMBA/TPA-induced skin cancer model, we find that PAQR4-deleted mice are resistant to chemical carcinogen-induced tumor formation. Collectively, our findings reveal that the steady-state level of CDK4 is controlled by the antagonistic actions between PAQR4 and SKP2, contributing to modulation of cell proliferation and tumorigenesis.

Enhanced synergy between Cu^(0) and Cu^(+) on nickel doped copper catalyst for gaseous acetic acid hydrogenation

As the substitution of common noble catalysts in the hydrogenation of carboxylic acid,a highly effective Cu-Ni/SiO_(2) catalyst was prepared by a novel stepwise ammonia evaporation method.Its performance in the gasphase hydrogenation of acetic acid was further examined.With the introduction of Ni dopant,more stable Cu^(δ+) sites,which can adsorb more acetic acid,were formed due to the electron transfer from Cu to Ni.This makes more Cu^(0) sites available for hydrogen adsorption,which was suggested as the rate-determining step in acetic acid hydrogenation.A conversion of 99.6% was successfully achieved on this new Cu/SiO_(2)-0.5Ni catalyst,accompanied by the ethanol selectivity of 90%.The incorporation of nickel between copper nanoparticles enhances the synergistic effect between Cu^(0) and Cu^(+).It also helps mitigate the aggregation of copper nanoparticles due to the Ostwald ripening effect induced by acetic acid and enhance the stability of copper catalyst in the conversion of carboxylic acid.