Performance enhancement and active sites identification of Cu-Cd bimetallic oxide derived catalysts for electrochemical CO_(2) reduction

The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.

刺葡萄STS基因克隆及其在不同光质下的表达水平

【目的】研究刺葡萄芪合酶(STS)基因的序列特征及其在不同光质处理下的表达水平,旨在为进一步解析STS基因通过响应光信号调控刺葡萄愈伤组织中白藜芦醇合成的分子机制提供依据。【方法】以刺葡萄愈伤组织为材料,利用逆转录PCR(RT-PCR)技术成功克隆获得了4个STS基因,对这些基因及其编码蛋白进行了生物信息学分析,并利用实时荧光定量PCR(RT-qPCR)检测其在不同光质下和不同培养阶段的表达水平。【结果】成功地从刺葡萄愈伤组织中克隆获得了VdSTS5、VdSTS6、VdSTS20、VdSTS21共4个基因,均含1179 bp完整开放阅读框(ORF),编码392个氨基酸残基,预测其编码的是亲水性、无信号肽的细胞质定位蛋白,磷酸化修饰主要发生在苏氨酸和丝氨酸位点上,蛋白质的二级结构主要由α-螺旋、无规则卷曲和延伸链组成,STS与查尔酮合成酶(CHS)的蛋白质序列具有高度同源性。4个VdSTS的蛋白质序列在系统进化树上处于3个不同的大分支中,其中,VdSTS5与VdSTS21处在不同的分支中,而VdSTS6与VdSTS20聚在同一分支中,葡萄属不同种之间的STS蛋白质序列相似度高,推测其可能具有相同的功能。启动子顺式作用元件预测发现,4个VdSTS启动子含有多个光响应元件,还含有转录因子识别和作用元件、激素作用元件等。光质显著影响4个VdSTS的表达,在白光、红光、黄光和黑暗处理下,VdSTS的总体表达水平较高,而在绿光和紫光处理下,VdSTS的总体表达水平较低;同时,VdSTS对不同光质的响应不仅存在着基因间的差异,还存在不同培养阶段的差异,VdSTS5在培养后期强烈响应黄光的调控,VdSTS6、VdSTS20在培养中期对黑暗和红光的响应最强,VdSTS21则在培养中期强烈响应红光的调控,这些基因表达水平的变化影响着刺葡萄愈伤组织中白藜芦醇的合成。【结论】4个VdSTS对光质的响应存在差异,可能在响应不同光质调控中对刺葡萄愈伤组织白藜芦醇的合成起到重要作用。

Tuning active sites in MoS_(2)-based catalysts via H_(2)O_(2)etching to enhance hydrodesulfurization performance

A H_(2)O_(2)etching strategy was adopted to introduce coordinatively unsaturated sites(CUS)on MoS_(2)-based catalysts for dibenzothiophene(DBT)hydrodesulfurization(HDS).The CUS concentrations on MoS_(2) slabs were finely regulated by changing the concentrations of H_(2)O_(2)solution.With the increasing H_(2)O_(2)concentrations(0.1–0.3 mol/L),The CUS concentrations on MoS_(2) slabs increased gradually.However,the high-concentration H_(2)O_(2)etching(0.5 mol/L)increased the MoOxSy and MoO_(3) contents on MoS_(2) slabs compared to etching with the H_(2)O_(2)concentration of 0.3 mol/L,which led to the less CUS concentration in the sulfided Mo–H-0.5 catalyst than in the sulfided Mo–H-0.3 catalyst.A microstructure-activity correlation indicated that the CUS introduced by H_(2)O_(2)etching on MoS_(2) slabs significantly enhanced DBT HDS.Different Co loadings were further introduced into Mo–H-0.3,which had the most CUS concentration,and the corresponding 0.2-CoMo catalyst with the highest CoMoS content(3.853 wt%)exhibited the highest reaction rate constant of 6.95×10^(−6)mol g^(−1)s^(−1)among these CoMo catalysts.

从STS到STSE的扩展:科学技术哲学研究的一个新动态

随着科学技术对环境影响的日益加剧,社会发展中的环境问题日益凸显,很多科学、技术与社会(STS)领域的问题需要从生态维度去考虑。在以往的STS研究中,虽然涉及一定生态环境内容,但还未充分突出其重要性、独立性。通过分析当前国内外STS研究动态,特别是其中涉及生态环境的部分,STS研究展现出向科学、技术、社会与环境(STSE)研究扩展的趋势。在这一扩展中,把环境视为一种独立要素,从而为原来的STS研究带来新的认知维度,建立“科学-技术-社会-环境”新的系统,具有一定启发意义。

作为STS方法与出路的人类学

STS (科学技术元勘)是一个跨学科领域,分解看是一个学科群,包括科学史、科学哲学、科学社会学等。概言之,它是关于科学/技术的社会/文化研究。中国的STS是从自然辩证法转型而来的,很多学者供职于哲学系。STS领域承继了西方哲学的某些气质,追求普遍性、绝对性、确定性,追求终极原因甚至唯一真理。现在的人类学则以文化相对主义为前提,可以消解STS中的这些观念。在STS的学术史上,有些学者也曾受到人类学的影响,并采用了人类学的方法,如SSK和科学实践哲学。然而,在STS尤其是科学哲学的学术范式中,普遍以文本为重中之重,忽视社会现实,更不关心个体的生命体验。人类学则以田野为基本方法,以田野为学术之基础。STS需要面对社会现实,可以从人类学中汲取观念和方法上的营养。博物学是STS领域的新范式,博物学与人类学在方法、理念和对象上,都存在交集。学科交汇是大势所趋,人类学与STS可以共生,相互建构。

基于STS理论视角对流行“减肥”观念及其问题的研究

减肥作为广泛流行的文化现象,是当下人们,尤其女性普遍关心的问题,人们也早已对各类打着“科学”“医学”旗号的减肥信息司空见惯。不恰当的减肥观念和行为会引起肥胖歧视、社会焦虑、饮食障碍等一系列社会和个人问题,这已引起国际相关学者的广泛关注和研究。结合已有的减肥研究文献,针对我国当下广为流传的、代表性的主要减肥观念、内容及其问题,进行科学(医学)基础和来源追溯,基于STS的理论视角进行综合讨论和分析,进而为深入理解和解决这一社会现实问题提供可能。

Efficient and reversible separation of NH_(3) by deep eutectic solvents with multiple active sites and low viscosities

The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.

Building Fe atom–cluster composite sites using a site occupation strategy to boost electrochemical oxygen reduction

The high-temperature pyrolysis process for preparing M–N–C single-atom catalyst usually results in high heterogeneity in product structure concurrently contains multiscale metal phases from single atoms(SAs),atomic clusters to nanoparticles.Therefore,understanding the interactions among these components,especially the synergistic effects between single atomic sites and cluster sites,is crucial for improving the oxygen reduction reaction(ORR)activity of M–N–C catalysts.Accordingly,herein,we constructed a model catalyst composed of both atomically dispersed FeN4 SA sites and adjacent Fe clusters through a site occupation strategy.We found that the Fe clusters can optimize the adsorption strength of oxygen reduction intermediates on FeN4 SA sites by introducing electron-withdrawing–OH ligands and decreasing the d-band center of the Fe center.The as-developed catalyst exhibits encouraging ORR activity with halfwave potentials(E1/2)of 0.831 and 0.905 V in acidic and alkaline media,respectively.Moreover,the catalyst also represents excellent durability exceeding that of Fe–N–C SA catalyst.The practical application of Fe(Cd)–CNx catalyst is further validated by its superior activity and stability in a metalair battery device.Our work exhibits the great potential of synergistic effects between multiphase metal species for improvements of singleatom site catalysts.

Effects of site preparation methods on soil physical properties and outplanting success of coniferous seedlings in boreal forests

This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess growth.In the rooting layer,240 soil samples were taken to determine physical properties.The study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina sites.However,reduced soil moisture was noted,particularly in mounds,resulting in increased aeration.In Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the mounds.Mounding treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration porosity.In the Myrtillus and Polytrichum sites,patch scarification had no effects on physical properties.In Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to diameter.In Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil treatments.Growing conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.

Zonal activation of molecular carbon dioxide and hydrogen over dual sites Ni-Co-MgO catalyst for CO_(2) methanation:Synergistic catalysis of Ni and Co species

An in-depth mechanism in zonal activation of CO_(2)and H2molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO_(2)methanation mechanism.The abundant surface nickel and cobalt components as active sites led to strong Ni-Co interaction with charge transfer from nickel to cobalt.Notably,electron-enriched Coδ-species participated in efficient chemisorption and activation of CO_(2)to generate monodentate carbonate.Simultaneously,plentiful available Ni0sites facilitated H2dissociation,thus CO_(2)and H2were smoothly activated at zones of Coδ-species and Ni0,respectively.Detailed in situ DRIFTS,quasi situ XPS,TPSR,and DFT calculations substantiated a new formate evolution mechanism via monodentate carbonate instead of traditional bidentate carbonate based on synergistic catalysis of Coδ-species and Ni0.The zonal activation of CO_(2)and H2by tuning electron behaviors of double-center catalysts can boost heterogeneous catalytic hydrogenation performance.

Atomically dispersed Fe sites on hierarchically porous carbon nanoplates for oxygen reduction reaction

Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air batteries.Although Fe-N-C single atom catalysts(SACs) have been hailed as the most promising candidate due to the optimal binding strength of ORR intermediates on the Fe-N_(4) sites,they suffer from serious mass transport limitations as microporous templates/substrates,i.e.,zeolitic imidazolate frameworks(ZIFs),are usually employed to host the active sites.Motivated by this challenge,we herein develop a hydrogen-bonded organic framework(HOF)-assisted pyrolysis strategy to construct hierarchical micro/mesoporous carbon nanoplates for the deposition of atomically dispersed Fe-N_(4) sites.Such a design is accomplished by employing HOF nanoplates assembled from 2-aminoterephthalic acid(NH_(2)-BDC) and p-phenylenediamine(PDA) as both soft templates and C,N precursors.Benefitting from the structural merits inherited from HOF templates,the optimized catalyst(denoted as Fe-N-C SAC-950) displays outstanding ORR activity with a high half-wave potential of 0.895 V(vs.reversible hydrogen electrode(RHE)) and a small overpotential of 356 mV at 10 mA cm^(-2) for the oxygen evolution reaction(OER).More excitingly,its application potential is further verified by delivering superb rechargeability and cycling stability with a nearly unfading charge-discharge gap of 0.72 V after 160 h.Molecular dynamics(MD) simulations reveal that micro/mesoporous structure is conducive to the rapid mass transfer of O_(2),thus enhancing the ORR performance.In situ Raman results further indicate that the conversion of O_(2) to~*O_(2)-the rate-determining step(RDS) for Fe-N-C SAC-950.This work will provide a versatile strategy to construct single atom catalysts with desirable catalytic properties.

Multifunctional catalytic sites regulation of atomic-scale iridium on orthorhombic-CoSe_(2)for high efficiency dual-functional alkaline hydrogen evolution and organic degradation

The earth-abundant and high-performance catalysts are crucial for commercial implementation of hydrogen evolution reaction(HER).Herein,a multifunctional site strategy to construct excellent HER catalysts by incorporating iridium(Ir)ions on the atomic scale into orthorhombic-CoSe2(Ir-CoSe_(2))was reported.Outstanding hydrogen evolution activity in alkaline media such as a low overpotential of 48.7 mV at a current density of 10 mA cm^(-2)and better performance than commercial Pt/C catalysts at high current densities were found in the Ir-CoSe_(2) samples.In the experiments and theoretical calculations,it was revealed that Ir enabled CoSe_(2)to form multifunctional sites to synergistically catalyze alkaline HER by promoting the adsorption and dissociation of H_(2)O(Ir sites)and optimizing the binding energy for H^(*)on Co sites.It was noticeable that the electrolytic system comprising the Ir-CoSe_(2)electrode not only produced hydrogen efficiently via HER,but also degraded organic pollutants(Methylene blue).The cell voltage of the dual-function electrolytic system was 1.58 V at the benchmark current density of 50 mA cm^(-2),which was significantly lower than the conventional water splitting voltage.It was indicated that this method was a novel strategy for designing advanced HER electrocatalysts by constructing multifunctional catalytic sites for hydrogen production and organic degradation.

Fe-N-C core-shell catalysts with single low-spin Fe(Ⅱ)-N_(4)species for oxygen reduction reaction and high-performance proton exchange membrane fuel cells

Fe-N-doped carbon materials(Fe-N-C)are promising candidates for oxygen reduction reaction(ORR)relative to Pt-based catalysts in proton exchange membrane fuel cells(PEMFCs).However,the intrinsic contributions of Fe-N_(4)moiety with different chemical/spin states(e.g.D1,D2,D3)to ORR are unclear since various states coexist inevitably.In the present work,Fe-N-C core-shell nanocatalyst with single lowspin Fe(Ⅱ)-N_(4)species(D1)is synthesized and identified with ex-situ ultralow temperature Mossbauer spectroscopy(T=1.6 K)that could essentially differentiate various Fe-N_(4)states and invisible Fe-O species.By quantifying with CO-pulse chemisorption,site density and turnover frequency of Fe-N-C catalysts reach 2.4×10^(-9)site g^(-1)and 23 e site~(-1)s^(-1)during the ORR,respectively.Half-wave potential(0.915V_(RHE))of the Fe-N-C catalyst is more positive(approximately 54 mV)than that of Pt/C.Moreover,we observe that the performance of PEMFCs on Fe-N-C almost achieves the 2025 target of the US Department of Energy by demonstrating a current density of 1.037 A cm^(-2)combined with the peak power density of 0,685 W cm^(-2),suggesting the critical role of Fe(Ⅱ)-N_(4)site(D1).After 500 h of running,PEMFCs still deliver a power density of 1.26 W cm^(-2)at 1.0 bar H_(2)-O_(2),An unexpected rate-determining step is figured out by isotopic labelling experiment and theoretical calculation.This work not only offers valuable insights regarding the intrinsic contribution of Fe-N_(4)with a single spin state to alkaline/acidic ORR,but also provides great opportunities for developing high-performance stable PEMFCs.

Understanding Bridging Sites and Accelerating Quantum Efficiency for Photocatalytic CO_(2) Reduction

We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.

Fe-N_(x) sites coupled with core-shell FeS@C nanoparticles to boost the oxygen catalysis for rechargeable Zn-air batteries

The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,Fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic activity.Precisely,atomically dispersed Fe-N_(x) sites supported on N/S-doped mesoporous carbon(NSC)coupled with FeS@C core-shell nanoparticles(FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis.Due to the presence of an in situ-grown conductive graphitic layer(shell),the FeS nanoparticles(core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions.Consequently,FAS-NSC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAS-NSC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based ZAB.This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR,with potential implications for energy conversion and storage technologies.

基于SITES的滨水后工业景观实践——以广州白鹅潭聚龙湾展示中心项目为例

可持续场地倡议(SITES)作为当前世界范围内评估景观可持续性的主流选择之一,为保护、改善和恢复健康生态系统所提供的效益及服务提供了具体的实践指导。滨水后工业景观具有较高的地理经济价值、较大的影响力和重要的示范性,是可持续设计落地与传播的重要实践类型。以中国内地首个获得SITES铂金级认证的后工业景观项目——广州白鹅潭聚龙湾展示中心景观项目为例,总结分析场地SITES对于滨水后工业景观实践在设计前评估、场址设计、施工维护与运营阶段的指导。通过对中国内地地区落地SITES的实践反思,总结了关注在地性资源与发挥项目带动性作用的整合思路。

Strain‑Induced Surface Interface Dual Polarization Constructs PML‑Cu/Bi_(12)O_(17)Br_(2) High‑Density Active Sites for CO_(2) Photoreduction

The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging.Herein,strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer(PML-Cu)and Bi_(12)O_(17)Br_(2)(BOB),which triggers the surface interface dual polarization of PML-Cu/BOB(PBOB).In this multi-step polarization,the built-in electric field formed between the interfaces induces the electron transfer from con-duction band(CB)of BOB to CB of PML-Cu and suppresses its reverse migration.Moreover,the surface polarization of PML-Cu further promotes the electron converge in Cu atoms.The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB,significantly promoting the adsorption and activation of CO_(2) and CO desorption.The conversion rate of CO_(2) photoreduction to CO for PBOB can reach 584.3μmol g-1,which is 7.83 times higher than BOB and 20.01 times than PML-Cu.This work offers valuable insights into multi-step polarization regulation and active site design for catalysts.

STS注射液联合营养治疗冠心病心绞痛的临床观察及对血清CK-MB、APN水平的影响

目的:观察丹参酮ⅡA磺酸钠(Sulfotanshinone Sodium,STS)注射液联合营养治疗冠心病心绞痛的临床疗效。方法:选取2020年1月至2022年10月在我院治疗的冠心病心绞痛患者122例,按照随机数字表法分为对照组和观察组,各61例。对照组给予60 mg STS注射液,观察组在对照组的基础上给予营养治疗。分析治疗2 w后疗效和不良反应发生率,采用血液流变仪测定血流动力学指标,采用全自动生化仪测定血脂指标,采用酶联免疫法测定血清肌酸激酶同工酶(Creatine Kinase Isoenzyme-MB,CK-MB)及脂联素(Adiponectin,APN)水平并对比两组间差异。结果:观察组的治疗有效率明显高于对照组(P<0.05)。治疗后,观察组的TC、TG、LDL-C、血浆黏度、全血粘度、纤维蛋白原及血细胞、CK-MB均显著低于对照组(P<0.05)。观察组的APN显著高于对照组(P<0.05)。结论:STS注射液联合营养治疗冠心病心绞痛,能提高临床疗效,改善心功能和血流动力学,且不良反应少。

基于STS教学模式的问题串教学——以“抗原检测试纸中单克隆抗体的制备”为例

单克隆抗体的制备作为一个微专题在高三二轮复习中经常出现,利用STS教学模式,结合抗原检测试纸这一生活用品,将与单克隆抗体有关的知识点(如免疫调节、基因工程、细胞培养等)进行串联,通过设置问题串,引导学生面对真实的生活问题,结合已有的知识及查阅相关资料,达到解决问题的目的,并在此过程中培养学生的核心素养。

STS教育在高中生物教学中的应用探究

通过文献综述和教育实践观察,分析了STS教育在高中生物课程中的重要性,以及它如何促进学生的科学素养和社会参与.研究发现,STS教育可以提高学生的科学思维能力,培养他们的社会责任感,并促进跨学科学习.最后,总结了在生物教学中应用STS教育的一些建议.