普通高校网球运动发展的“催化剂”效应研究

根据我国普通高校网球运动发展现状调查,归纳了网球场地、网球运动人口和教师队伍与学生之间关系,同时发展和普及高校网球运动现实意义。在此基础上,探讨了女网国手崛起、网球文化、全国大学生网球赛和校内网球赛推动高校网球运动发展的"催化剂"效应。最后,论述了普通高校网球运动发展要解决学校重视程度、场地、师资的问题。

基于水合物生成的多机制耦合储存天然气实验研究

探索了基于水合物生成的多机制耦合储存天然气的方法,以提高储存效率并降低环境影响。对不同温度、压力以及不同有机催化剂的使用对水合物生成和稳定性的影响进行了实验研究。结果表明:在低温(-5~15℃)和高压(3~12MPa)条件下,使用特定催化剂显著提高了水合物的生成速率和稳定性。特别是在-5℃和12MPa条件下,使用CAT-4502催化剂时,水合物的生成量达到最大值650m L,而稳定性评分(分解时间)高达84h。此外,水合物技术在温室气体排放和能源消耗方面表现出优越性,相比传统储存方法,可减少约40%的温室气体排放和38%的能源消耗。本研究为天然气的高效储存提供了新的视角,并展示了水合物技术在环境友好性和经济可行性方面的潜力。

乙醇蒸汽重整制氢镍基催化剂的尺度效应与构效关系

考察了Ni基催化剂镍颗粒尺度与乙醇蒸汽重整活性、稳定性的构效关系.通过改良St?ber法制备了镍颗粒尺度可控的Ni@Si O2壳核型催化剂,研究了具有不同镍颗粒尺度的Ni@Si O2壳核型催化剂,发现催化剂乙醇转化频率随着镍颗粒尺度的增加而增加,当镍颗粒尺寸达到30 nm以上时,变化不再明显.镍颗粒尺度对催化剂稳定性也有影响.镍颗粒尺度越大,催化剂积碳速率越快,稳定性越差.结果表明,适当的镍颗粒尺度对催化剂活性和稳定性均至关重要.

Synergistic effect of heterogeneous single atoms and clusters for improved catalytic performance

Electrocatalytic water splitting provides an efficient method for the production of hydrogen.In electrocatalytic water splitting,the oxygen evolution reaction(OER)involves a kinetically sluggish four-electron transfer process,which limits the efficiency of electrocatalytic water splitting.Therefore,it is urgent to develop highly active OER catalysts to accelerate reaction kinetics.Coupling single atoms and clusters in one system is an innovative approach for developing efficient catalysts that can synergistically optimize the adsorption and configuration of intermediates and improve catalytic activity.However,research in this area is still scarce.Herein,we constructed a heterogeneous single-atom cluster system by anchoring Ir single atoms and Co clusters on the surface of Ni(OH)_(2)nanosheets.Ir single atoms and Co clusters synergistically improved the catalytic activity toward the OER.Specifically,Co_(n)Ir_(1)/Ni(OH)_(2)required an overpotential of 255 mV at a current density of 10 mA·cm^(−2),which was 60 mV and 67 mV lower than those of Co_(n)/Ni(OH)_(2)and Ir1/Ni(OH)_(2),respectively.The turnover frequency of Co_(n)Ir_(1)/Ni(OH)_(2)was 0.49 s^(−1),which was 4.9 times greater than that of Co_(n)/Ni(OH)_(2)at an overpotential of 300 mV.

Enhancing selectivity in acidic CO_(2) electrolysis:Cation effects and catalyst innovation

The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficiency is limited by(bi)carbonates formation.Acidic media have emerged as a solution,addressing the(bi)carbonates challenge but introducing the issue of the hydrogen evolu-tion reaction(HER),which reduces CO_(2) conversion efficiency in acidic environments.This review focuses on enhancing the selectivity of acidic CO_(2) electrolysis.It commences with an overview of the latest advancements in acidic CO_(2) electrolysis,focusing on product selectivity and electrocatalytic activity enhancements.It then delves into the critical factors shaping selectivity in acidic CO_(2) electrolysis,with a special emphasis on the influence of cations and catalyst design.Finally,the research challenges and personal perspectives of acidic CO_(2) electrolysis are suggested.

金属氧化物纳米催化的形貌效应

纳米结构催化剂的设计与制备是多相催化的核心问题之一.提高催化活性的传统方法是减小催化剂粒子的尺寸以暴露更多的表面活性位,即纳米催化中的尺寸效应,但这种方法往往带有一定程度的经验性和随机性.近年来,随着纳米材料科学的快速发展,在溶液体系中通过自下而上的合成技术已经可以在纳米尺度上有效调变固体催化剂粒子的形貌.通过纳米催化材料的形貌可控合成,可选择性地暴露高活性或特定能量晶面,从而大幅度提升催化反应活性、选择性和稳定性,也就是纳米催化中的形貌效应,这也是当前纳米催化研究的热点之一.本文以作者近年来研究的Co3O4、CeO2和Fe2O3为重点,总结了纳米结构金属氧化物在多相催化反应中的形貌效应,分析了氧化物暴露晶面的化学性质对催化性能的作用机制.这种基于形貌效应的纳米催化不仅加深了在纳米尺度甚至原子层次上对催化剂构-效关系的认知,而且对设计和开发实用高效催化剂也具有重要的理论价值.

数字化转型与数字化无形资本匹配的创新效应研究

如何充分实现数字经济与实体经济深度融合,进而实现高质量创新,是中国经济高质量发展的关键问题。无形资本是影响数字化转型不能忽视的关键因素,本文以此为切入点来揭示数字化转型创新潜能释放的内在机制。本文构建了包含数字化无形资本的内生增长模型,解释了数字化无形资本促进创新的内在机理。基于2010—2019年中国沪深A股上市企业数据检验发现:数字化无形资本具有创新催化剂效应,企业数字化转型和数字化无形资本的协调匹配能显著倍增数字经济创新产出;数字化无形资本的创新催化剂效应主要是通过创新效率提升和创新扩散促进两种机制来实现;异质性分析表明,数据及数据分析技术、高端人才资本对数字经济创新产出的催化剂效应更为显著;数字化无形资本会强化领先企业的创新优势而产生极化效应,企业间数字化无形资本鸿沟的拉大会阻碍社会整体的创新。据此,促进数字经济和实体经济深度融合,最大化释放数字经济促进创新潜能,应重视企业数字化无形资本的积累,形成激励数字化无形资本积累和驱动创新的系统制度,并消除企业间数字化无形资本鸿沟。

新农保对农村中老年人劳动供给时间的影响——基于年龄与家庭收入的异质性分析

依据CHARLS数据,采用PSM-DID方法,考量新农保对农村中老年人劳动供给时间的影响。结果显示:在考虑时滞效应的情况下,新农保对农村中老年人,特别是60岁以下中老年人的劳动供给具有显著负向影响,同时对家庭收入较高群体的劳动力供给负向影响更为显著。

Photocatalysis fundamentals and surface modification of TiO_2 nanomaterials

As a green and sustainable technology,heterogeneous photocatalysis using semiconductors has received much attention during the past decades because of its potential to address energy and environmental problems. Among various semiconductors,TiO2 has been regarded as the best and most widely investigated photocatalyst in the past 10 years. Based on the fundamentals of photocatalysis and surface chemistry of TiO2 nanomaterials,we herein summarize and discuss the achievements in the different surface modification strategies employed to date such as surface doping and sensitization,construction of surface heterojunctions,loading of nano-sized co-catalysts,increase in the accessible surface areas,and usage of surface F effects and exposure of highly reactive facets. Especially,the interesting synergistic effects of these different surface modification strategies deserve more attention in the near future. Studying these important advances in photocatalysis fundamentals,and surface chemistry and modification may offer new opportunities for designing highly efficient TiO2-based and non-TiO2-based photocatalysts for solar fuel production,environmental remediation,organic photosynthesis,and other related fields such as solar cell device fabrication,thermal catalysis,and separation and purification.

Effects of Co_3O_4 nanocatalyst morphology on CO oxidation:Synthesis process map and catalytic activity

This study focuses on drawing a hydrothermal synthesis process map for Co3O4 nanoparticles with various morphologies and investigating the effects of Co3O4 nanocatalyst morphology on CO oxidation.A series of cobalt-hydroxide-carbonate nanoparticles with various morphologies（i.e.,nanorods,nanosheets,and nanocubes） were successfully synthesized,and Co3O4 nanoparticles were obtained by thermal decomposition of the cobalt-hydroxide-carbonate precursors.The results suggest that the cobalt source is a key factor for controlling the morphology of cobalt-hydroxide-carbonate at relatively low hydrothermal temperatures（≤ 140℃）.Nanorods can be synthesized in CoCl2 solution,while Co（NO3）2 solution promotes the formation of nanosheets.Further increasing the synthesis temperature（higher than 140 ℃） results in the formation of nanocubes in either Co（NO3）2 or CoCl2 solution.The reaction time only affects the size of the obtained nanoparticles.The presence of CTAB could improve the uniformity and dispersion of particles.Co3O4 nanosheets showed much higher catalytic activity for CO oxidation than nanorods and nanocubes because it has more abundant Co^（3＋） on the surface,much higher reducibility,and better oxygen desorption capacity.

Insights into facet-dependent reactivity of CuO–CeO2 nanocubes and nanorods as catalysts for CO oxidation reaction

Copper–ceria(Cu O–CeO2) catalysts have been known to be very effective for the oxidation of CO, and their chemical behavior has been extensively studied during the last decades. However, the effect of different CeO2 crystal surfaces on the catalytic activity of Cu O–CeO2 for the oxidation of CO is still unclear and should be further elucidated. In this study, we deposited 1 wt% Cu on mostly {100}-exposed CeO2 nanocubes(1 Cu Ce NC) and mostly {110}-exposed CeO2 nanorods(1 Cu Ce NR), respectively. Both 1 Cu Ce NC and 1 Cu Ce NR have been used as catalysts for the oxidation of CO and achieved 100% and 50% CO conversion at 130 ℃, respectively. The differences in the catalytic activity of 1 Cu Ce NC and 1 Cu Ce NR were analyzed using temperature-programmed reduction of H2 and temperature-programmed desorption of CO techniques. The results confirmed the excellent reducibility of the 1 Cu Ce NC catalyst, which was attributed to the weak interactions between Cu and the CeO2 support. Moreover, in situ diffuse reflectance infrared Fourier-transform spectroscopy studies indicated that the {100} planes of 1 Cu Ce NC facilitated the generation of active Cu(I) sites, which resulted in the formation of highly reactive Cu(I)-CO species during the oxidation of CO. Both the excellent redox properties and effective CO adsorption capacity of the 1 Cu Ce NC catalyst increased its catalytic reactivity.

Enhanced photocatalytic H_(2) production performance of CdS hollow spheres using C and Pt as bi-cocatalysts

Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously.Herein,carbon@CdS composite hollow spheres(C@CdS-HS)are fabricated via a facile hydrothermal method using porous carbon hollow spheres(C-HS)as the template.The C@CdS-HS shows an excellent photocatalytic H2-generation rate of 20.9 mmol h^(−1) g^(−1)(apparent quantum efficiency of 15.3%at 420 nm),with 1.0 wt%Pt as a cocatalyst under simulated sunlight irradiation;this rate is 69.7,13.9,and 3.9 times higher than that obtained with pure CdS hollow spheres(CdS-HS),C@CdS-HS,and CdS-HS/Pt,respectively.The enhanced photocatalytic H_(2)-evolution activity of C@CdS-HS/Pt is due to the synergistic effect of C and Pt as the bi-cocatalyst.The C-HS serves not only as an active site provider but also as an electron transporter and reservoir.Moreover,C-HS has a strong photothermal effect that is induced by near infrared light,which kinetically accelerates the H_(2)-production reaction.Additionally,the underlying charge transfer pathway and process from CdS to C−HS is revealed.This work highlights the potential application of C-HS-based nanocomposites in solar-to-chemical energy conversion.

SiO_2-supported Au-Ni bimetallic catalyst for the selective hydrogenation of acetylene

Supported Au catalysts have been reported to exhibit high ethylene selectivity in the hydrogenation of acetylene,but the conversion is relatively low.Adding a second metal to Au has proven to be a promising approach to enhance its catalytic performance in acetylene hydrogenation.In this work,SiO2‐supported Au‐Ni bimetallic catalysts were synthesized and investigated in the selective hydrogenation of acetylene.The Au‐Ni bimetallic catalysts exhibited much higher catalytic performance than that of the corresponding monometallic Au or Ni catalysts.By tuning the reduction temperature and/or Ni loading,we obtained an Au‐Ni/SiO2catalyst with optimal performance.The results of transmission electron microscopy imaging revealed that the Au‐Ni bimetallic particles were highly dispersed on the SiO2support.Meanwhile,analysis of the bimetallic catalyst by energy‐dispersive X‐ray spectroscopy,high‐resolution transmission electron microscopy,and in situ diffuse reflectance infrared Fourier transform spectroscopy demonstrated the formation of Au‐Ni alloy,which contributed to the synergistic effect between Au and Ni in the hydrogenation of acetylene.

MgO and Au nanoparticle Co-modified g-C_(3)N_(4)photocatalysts for enhanced photoreduction of CO_(2)with H_(2)O

The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar irradiation.The best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h reaction.We investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,respectively.The characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary photocatalyst.The cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge transfer.Meanwhile,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using H2O.This study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.

Synergistic effect of metallic nickel and cobalt oxides with nitrogen-doped carbon nanospheres for highly efficient oxygen evolution

The most energy-inefficient step in the oxygen evolution reaction(OER), which involves a complicated four-electron transfer process, limits the efficiency of the electrochemical water splitting. Here, well-defined Ni/Co3O4 nanoparticles coupled with N-doped carbon hybrids(Ni/Co3O4@NC) were synthesized via a facile impregnation-calcination method as efficient electrocatalysts for OER in alkaline media. Notably, the impregnation of the polymer with Ni and Co ions in the first step ensured the homogeneous distribution of metals, thus guaranteeing the subsequent in situ calcination reaction, which produced well-dispersed Ni and Co3O4 nanoparticles. Moreover, the N-doped carbon matrix formed at high temperatures could effectively prevent the aggregation and coalescence, and regulate the electronic configuration of active species. Benefiting from the synergistic effect between the Ni, Co3O4, and NC species, the obtained Ni/Co3O4@NC hybrids exhibited enhanced OER activities and remarkable stability in an alkaline solution with a smaller overpotential of 350 m V to afford 10 m A cm-2, lower Tafel slope of 52.27 m V dec-1, smaller charge-transfer resistance, and higher double-layer capacitance of 25.53 m F cm-2 compared to those of unary Co3O4@NC or Ni@NC metal hybrids. Therefore, this paper presents a facile strategy for designing other heteroatom-doped oxides coupled with ideal carbon materials as electrocatalysts for the OER.

Support Effects on Thiophene Hydrodesulfurization over Co-Mo-Ni/Al_2O_3 and Co-Mo-Ni/TiO_2-Al_2O_3 Catalysts

A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst （SC） had aromatic structure, composed of carbon enriched inner core, and oxygen-containing （SO3H, COOH, OH） groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts （strong-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five （HZSM-5）, sulfated zir-conia） in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.

Tandem Lewis acid catalysis for the conversion of alkenes to 1,2‐diols in the confined space of bifunctional TiSn‐Beta zeolite

The generation of multifunctional isolated active sites in zeolite supports is an attractive method for integrating multistep sequential reactions into a single‐pass tandem catalytic reaction.In this study,bifunctional TiSn‐Beta zeolite was prepared by a simple and scalable post‐synthesis approach,and it was utilized as an efficient heterogeneous catalyst for the tandem conversion of alkenes to 1,2‐diols.The isolated Ti and Sn Lewis acid sites within the TiSn‐Beta zeolite can efficiently integrate alkene epoxidation and epoxide hydration in tandem in a zeolite microreactor to achieve one‐step conversion of alkenes to 1,2‐diols with a high selectivity of>90%.Zeolite confinement effects result in high tandem rates of alkene epoxidation and epoxide hydration as well as high selectivity toward the desired product.Further,the novel method demonstrated herein can be employed to other tandem catalytic reactions for sustainable chemical production.

Doping effect of cations(Zr^(4+),Al^(3+),and Si^(4+)) on MnO_x/CeO_2 nano-rod catalyst for NH_3-SCR reaction at low temperature

Thermally stable Zr4+, Al3+, and Si4+ cations were incorporated into the lattice of CeO2 nano‐rods (i.e., CeO2‐NR) in order to improve the specific surface area. The undoped and Zr4+, Al3+, and Si4+ doped nano‐rods were used as supports to prepare MnOx/CeO2‐NR, MnOx/CZ‐NR, MnOx/CA‐NR, and MnOx/CS‐NR catalysts, respectively. The prepared supports and catalysts were comprehensively characterized by transmission electron microscopy (TEM), high‐resolution TEM, X‐ray diffraction, Raman and N2‐physisorption analyses, hydrogen temperature‐programmed reduction, ammonia temperature‐programmed desorption, in situ diffuse reflectance infrared Fourier‐transform spectroscopic analysis of the NH3 adsorption, and X‐ray photoelectron spectroscopy. Moreover, the catalytic performance and H2O+SO2 tolerance of these samples were evaluated through NH3‐selective catalytic reduction (NH3‐SCR) in the absence or presence of H2O and SO2. The obtained results show that the MnOx/CS‐NR catalyst exhibits the highest NOx conversion and the lowest N2O concentration, which result from the largest number of oxygen vacancies and acid sites, the highest Mn4+ content, and the lowest redox ability. The MnOx/CS‐NR catalyst also presents excellent resistance to H2O and SO2. All of these phenomena suggest that Si4+ is the optimal dopant for the MnOx/CeO2‐NR catalyst.

Correlation between catalytic activity of supported gold catalysts for carbon monoxide oxidation and metal–oxygen binding energy of the support metal oxides

The effect of a wide variety of metal oxide （MOx） supports has been discussed for CO oxidation on nanoparticulate gold catalysts. By using typical co‐precipitation and deposition–precipitation methods and under identical calcination conditions, supported gold catalysts were prepared on a wide variety of MOx supports, and the temperature for 50%conversion was measured to qualita‐tively evaluate the catalytic activities of these simple MOx and supported Au catalysts. Furthermore, the difference in these temperatures for the simple MOx compared to the supported Au catalysts is plotted against the metal–oxygen binding energies of the support MOx. A clear volcano‐like correla‐tion between the temperature difference and the metal–oxygen binding energies is observed. This correlation suggests that the use of MOx with appropriate metal–oxygen binding energies （300–500 kJ/atom O） greatly improves the catalytic activity of MOx by the deposition of Au NPs.

Synergetic photocatalytic and thermocatalytic reforming of methanol for hydrogen production based on Pt@TiO_(2) catalyst

In order to efficiently produce H_(2),conventional methanol‐water thermocatalytic(TC)reforming requires a very high temperature due to high Gibbs free energy,while the energy conversion efficiency of methanol‐water photocatalytic(PC)reforming is far from satisfaction because of the kinetic limitation.To address these issues,herein,we incorporate PC and TC processes together in a specially designed reactor and realize simultaneous photocatalytic/thermocatalytic(PC‐TC)reforming of methanol in an aqueous phase.Such a design facilitates the synergetic effect of the PC and TC process for H_(2) production due to a lower energy barrier and faster reaction kinetics.The methanol‐water reforming based on the optimized 0.05%Pt@TiO_(2) catalyst delivers an outstanding H_(2) production rate in the PC‐TC process(5.66μmol H_(2)·g^(‒1) catalyst·s^(‒1)),which is about 3 and 7 times than those of the TC process(1.89μmol H_(2)·g^(‒1) catalyst·s^(‒1))and the PC process(0.80μmol H_(2)·g^(‒1) catalyst·s^(‒1)),respectively.Isotope tracer experiments,active intermediate trapping experiments,and theoretical calculations demonstrate that the photo‐generated holes and hydroxyl radicals could enhance the methanol dehydrogenation,water molecule splitting,and water‐gas shift reaction,while high temperature accelerates reaction kinetics.The proposed PC‐TC reforming of methanol for hydrogen production can be a promising technology to solve the energy and environmental issue in the closed‐loop hydrogen economy in the near future.