“实验室安全管理规范与培训”案例教学改革与实践

为加强实验室安全与学生素养之间的联系,提升研究生实验室安全管理规范与培训课程的教学效果,本文提出了以实验室安全知识教育为核心的案例教学法。在深入研究了实验室安全管理课程的教学现状后,提出了课程教学改革实践方法,譬如提高专业针对性、丰富教学案例内容、理论联系实践、复现与深化教学知识、改革考核方法、重视教学效果评价,通过抓住典型案例与课程知识有机融合,让课程案例教学更贴近教学实际与学生实践;通过翻转课堂的授课方法,教师有效引导学生去感知、体会和思考,用科学隐性的教学方法来进行案例教学工作,有效促进学生正确安全价值观的形成与发展;伴随授课方式和考核方式的改革,开展实践育人,构筑丰富立体的“实验室安全管理规范与培训”案例构建与案例教学育人矩阵,形成切实有效、便于操作和推广的教学模式。

基于“三全育人”理念的大学化学课程思政案例构建与实践

对部分大学化学课程的教学理念和教学内容进行改革和探索。通过知识传授与价值引领双轨并行,构建了以大学化学知识为主体,以提升大学生的家国人文情怀、科学文化素养、科学思维方法为主导的大学化学课程的思政教学体系。通过与课程知识的有机结合,开展爱国主义、哲学辩证思想、认识发展观、科学素养、品格意志力、社会规则秩序和安全意识等七个育人思想,对大学化学课程思政的设计理念、具体案例和实施方法进行介绍。

Facile preparation of N-doped corncob-derived carbon nanofiber efficiently encapsulating Fe2O3 nanocrystals towards high ORR electrocatalytic activity

Facile preparation of cost-effective and durable porous carbon-supported non-precious-metal/nitrogen electrocatalysts for oxygen reduction reaction(ORR)is extremely important for promoting the commercialized applications of such catalysts.In this work,the FeCl3-containing porphyrinato iron-based covalent porous polymer(FeCl3·FeP or-CPP)was fabricated in-situ onto porous corncob biomass supports via a simple one-pot method.Subsequent thermal-reduction pyrolysis at 700℃-900℃with CO2 gas as an activating agent resulted in Fe2O3-decorated and N-doped graphitic carbon composite Fe2O3@NC&bio-C with a high degree of graphitization of Fe-involved promotion during pyrolysis(Fe2O3=FeCl3·FePor-CPP derived Fe2O3;NC=N-doped graphene analog;bio-C=the corncob-derived hierarchically porous graphitic biomass carbon framework).The derivedα-Fe2O3 andγ-Fe2O3 nanocrystals(5-10 nm particle diameter)were all immobilized on the N-doped bio-C micro/nanofibers.Notably,the Fe2O3@NC&bio-C obtained at the pyrolysis temperature of 800℃(Fe2O3@NC&bio-C-800),exhibited unusual ORR catalytic efficiency via a 4-electron pathway with the onset and half-wave potentials of 0.96 V and 0.85 V vs.RHE,respectively.In addition,Fe2O3@NC&bio-C-800 also exhibited a high and stable limiting current density of-6.0 mA cm-2,remarkably stability(larger than 91%retention after 10000 s),and good methanol tolerance.The present work represents one of the best results for iron-based biomass material ORR catalysts reported to date.The high ORR activity is attributed to the uniformly distributedα-Fe2O3 andγ-Fe2O3 nanoparticles on the N-enriched carbon matrix with a large specific surface area of 772.6 m^2 g^-1.This facilitates favor faster electron movement and better adsorption of oxygen molecules on the surface of the catalyst.Nevertheless,comparative studies on the structure and ORR catalytic activity of Fe2O3@NC&bioC-800 with Fe2O3@bio-C-800 and NC&bio-C-800 clearly highlight the synergistic effect of the coexisting Fe2O3 nanocrystals,NC,and bio-C on the ORR performance.

Metal-organic framework derived NiFe_(2)O_(4)/FeNi_(3)@C composite for efficient electrocatalytic oxygen evolution reaction

Reducing the cost and improving the electrocatalytic activity are the key to developing high efficiency electrocatalysts for oxygen evolution reaction(OER).Here,bimetallic NiFe-based metal-organic framework(MOF)was prepared by solvothermal method,and then used as precursor to prepare NiFe-based MOF-derived materials by pyrolysis.The effects of different metal ratios and pyrolysis temperatures on the sample structure and OER electrocatalytic performance were investigated and compared.The experimental results showed that when the metal molar ratio was Fe:Ni=1:5 and the pyrolysis temperature was 450℃,the sample(FeNi_(5)-MOF-450)exhibits a composite structure of Ni Fe_(2)O_(4)/FeNi_(3)/C and owns the superior electrocatalytic activity in OER.When the current density is 100 mA·cm^(-2),the overpotential of the sample was 377 mV with Tafel slope of 56.2 mV·dec^(-1),which indicates that FeNi_(5)-MOF-450 exhibits superior electrocatalytic performance than the commercial RuO_(2).Moreover,the long-term stability of FeNi_(5)-MOF-450 further promotes its development in OER.This work demonstrated that the regulatory methods such as component optimization can effectively improve the OER catalytic performance of NiFe-based MOF-derived materials.

Atomically thin defect-rich Ni-Se-S hybrid nanosheets as hydrogen evolution reaction electrocatalysts

Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalcogenides(TMDs)materials with large specific surface area and abundant catalytic active sites can significantly enhance their catalytic activities.Herein,we design and synthesize an atomically thin Ni-Se-S based hybrid nanosheet(NiSe1.2S0.8)via a simple solvothermal method,the thickness of NiSe1.2S0.8 nanosheets is only about 1.1 nm.Benefiting from the ultrathin nanostructure and rich defects,the optimal NiSe1.2S0.8 exhibits good electrocatalytic activity with the overpotential of 144 mV at−10 mA·cm−2,a small Tafel slope of 59 mV·dec−1,and outstanding catalytic stability in acid electrolyte for HER.The theoretical results show that hybrid electrocatalyst by S incorporation possesses the optimal adsorption free energy of hydrogen(ΔGH*).This study provides a simple method to synthesize a highperformance multicomponent electrocatalysts with the ultrathin nanostructures and abundant defects.

Recent progress of two-dimensional metal-organic-frameworks:From synthesis to electrocatalytic oxygen evolution

High-performance electrocatalysts for oxygen evolution reaction(OER)are crucial for water splitting and metal-air batteries.Twodimensional(2D)metal-organic framework(MOF)has become a new class of efficient OER electrocatalysts due to the rich coordination unsaturated metal nodes,large specific surface area,and adjustable structures.In addition,because inheriting the original microstructure of MOFs and having stronger chemical and mechanical stability,metal/alloy/oxide,metal sulfide/selenide/phosphide,and other compounds derived from 2D MOFs have also shown their unique OER catalytic ability.Here,we briefly introduced the existing reaction mechanism and evaluation parameters of catalyst performance of OER,introduced the synthesis methods and corresponding characterization techniques of 2D MOFs and their derivatives,and summarized the latest progress of 2D MOFs and their derivatives as OER catalysts.Finally,we put forward some views and suggestions on the existing problems hindering the development of 2D MOFs as OER for advancing the field.

Ligand controlled structure of cadmium(Ⅱ) metal-organic frameworks for fluorescence sensing of Fe^(3+) ion and nitroaromatic compounds

Three cadmium(II) metal-organic frameworks(MOFs) based on tetracarboxylate ligands, namely[Cd_2(TTTA)(DMF)_3]·2 DMF(1),[Cd_2(TB)(H_2O)_4]·3DMF·H_2O(2)and [Cd(TEB)_(0.5)].2 DMF.4 H_2O(3) have been designed and synthesized. Complex 1 is a 2-dimensional(2 D) 3,4-connected network with 3,4 L13 topology, complex 2 features a 3-dimensional(3D) 3,4-connected tfa topology with a 2-fold interpenetrating structure and complex 3 has a 3D 4-connected dia topology with a 4-fold interpenetrating structure. Interestingly, 2 exhibits permanent pores and selective adsorption of CO_2 over CH_4. In addition, 2 shows fluorescence sensing of Fe^(3+) ion and rapid detection of nitroaromatic compounds(NACs) through fluorescence quenching.

A 3D Ba-MOF for selective adsorption of CO_(2)/CH_(4)and CO_(2)/N_(2)

An unexpected in-situ hydrolysis reaction occurred during the solvothermal reaction of N,N’-bis(4-carboxy-2-methylphenyl)pyromellitic di-imide)and Ba(NO3)2,and a novel porous Ba-MOF,[H_(2)N(CH_(3))_(2)]_(0.5)[Ba_(1.5)(L)(DMA)]·1.5 DMA·1.5 H_(2)O(UPC-70,H_(3)L=2-(4-ca rboxy-2-methylphenyl)-1,3-dioxoisoindoline-5,6-dicarboxylic acid,DMA=N,N-dimethylacetamide),was obtained on the basis of the partial hydrolysate.The as-synthesized 3 D network with 1 D open channels of different sizes(24 A and 10 A)contains abundant open metal sites after removal of solvents,which is conducive to the preferential adsorption of CO_(2).The subsequent gas sorption measurement reveals the high separation selectivity of UPC-70 for CO_(2)/CH_(4)(15)and CO_(2)/N_(2)(32)at ambient conditions,and GCMC theoretical simulation provides good verification of the experimental results,indicating that UPC-70 is a potential candidate for CO_(2)capture from flue gas and natural gas.

Two-dimensional cobalt metal-organic frameworks for efficient C_3H_6/CH_4 and C_3H_8/CH_4 hydrocarbon separation

A Co-based two-dimensional（2 D） microporous metal-organic frameworks, [Co2（TMTA）（DMF）2（H2O）2]·NO3-·DMF（UPC-32） has been synthesized based on 4,4’,4’’-（2,4,6-trimethylbenzene-1,3,5-triyl）tribenzoic acid（H3TMTA）. UPC-32 features a 2 D microporous framework exhibits high adsorption of H2（118.2 cm3/g, 1.05 wt%, at 77 K）, and adsorption heat（Qst） of CO2（34–46 k J/mol）. UPC-32 with narrow distance between layers（3.8 ？） exhibits high selectivity of C3H6/CH4（31.46） and C3H8/CH4（28.04） at298 K and 1 bar. It is the first 2 D Co-MOF that showed selective separation of C3 hydrocarbon from CH4.

Two alkynyl functionalized Co（Ⅱ）-MOFs as fluorescent sensors exhibiting selectivity and sensitivity for Fe3+ and nitroaromatic compounds

Two Co(II)-MOFs with different structures were successfully synthesized under the premise of designing two ligands containing alkynyl functional groups. Complexes 1 ([Co(TEPA)(TPT)2/3]·2DMF·H2O) and 2 ([Co(EPA)(TPT)]·1.5DMF·1.5H2O) show excellent luminescence properties. Meanwhile, as fluorescent sensors, complexes 1 and 2 exhibit selectivity and sensitivity for Fe3+ with the Ksv of 1.520 ×104 L/mol and 3.543 ×104 L/mol, which can rapidly detect nitroaromatic compounds in methanol and ethanol, especially for 2,4-NPH through fluorescence quenching with high quenching efficiency. In particular, the Ksv value of complexes 1 and 2 towards 2,4-NPH can reach up to 1.627 ×105 L/mol and 9.600 ×104 L/mol, demonstrating that complexes 1 and 2 are good candidates for the identification and detection of Fe3+and nitroaromatic compounds.

Phosphorus-doped iron-nitrogen-carbon catalyst with pentacoordinated single atom sites for efficient oxygen reduction

Single-atomic Fe-N4 is the well-acknowledged active site in iron-nitrogen-carbon(Fe-N-C)material for oxygen reduction reaction(ORR).The adjusting of the electronic distribution of Fe-N4 is promising for further enhancing the performance of the Fe-N-C catalyst.Herein,a phosphorus(P)-doped Fe-N-C catalyst with penta-coordinated single atom sites(FeNPC)is reported for efficient oxygen reduction.Fe K-edge X-ray absorption spectroscopy(XAS)verifies the coordination environment of single Fe atom,while density functional theory(DFT)calculations reveal that the penta-coordination and neighboring doped P atoms can simultaneously change the electronic distribution of Fe-N_(4)and its adsorption strength of key intermediates,reducing the reactionfree energy of the potential-limiting step.Electrochemical tests validate the remarkable intrinsic ORR activity of FeNPC in alkaline media(a half-wave potential(E_(1/2))of 0.904 V vs.reversible hydrogen electrode(RHE)and limited current density(JL)of 6.23 mA·cm^(−2))and an enhanced ORR performance in neutral(E_(1/2)=0.751 V,J_(L)=5.27 mA·cm^(−2))and acidic media(E_(1/2)=0.735 V,JL=5.82 mA·cm^(−2))with excellent stability,highlighting the benefits of optimizing the local environment of singleatomic Fe-N4.

Ultrahigh Hydrogen Uptake in an Interpenetrated Zn_(4)O-Based Metal–Organic Framework

As a highly promising candidate for hydrogen storage,crucial to vehicles powered by fuel cells,metal–organic frameworks(MOFs)have attracted the attention of chemists in recent decades.H_(2) uptake in an MOF is influenced by many factors such as pore size,ligand functionalization,and open metal sites.The synergistic effect of these factors can significantly enhance the H_(2) uptake in an MOF.Herein,we report a twofold interpenetrated MOF(UPC-501)based on a Zn_(4)O(COO)_(6)secondary building unit with the H_(2) uptake of 14.8 mmol g^(−1)(2.96 wt%)at 77 K and 0.1 MPa.This uptake is the highest among all the reported porous Zn-based MOF materials.Both experimental and theoretical results confirm that the reduced pore size derived from twofold interpenetration and the imidazole-functionalized ligand are responsible for the extremely high H_(2) uptake of UPC-501.