河北师范大学国家级化学一流专业建设探索与实践

教育是国之大计、党之大计,教师是立教之本、兴教之源。以河北师范大学化学专业建设为例,从课程体系的构建、“金课”建设、实践教学和教学管理与评价四个方面,探讨地方高等师范院校如何立足师范教育开展一流化学专业建设,以实现培养“国家基础教育事业改革发展战略需求的德才兼备的骨干师资”的人才培养目标。

The effect of transition metal ions (M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)) on the chemical synthesis polyaniline as counter electrodes in dye-sensitized solar cells

The effect of transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investigated.PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide(I^-/I_3^-) redox couples. The power conversion efficiency(η) of PANI CEs doped with Mn^(2+),Ni^(2+),Co^(2+) (4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cu^(2+)decreased the power conversion efficiency of PANI CE(PANI-Cu^(2+) η = 1.41%). The electrical properties of the PANI, PANI-Ni^(2+), PANI-Co^(2+),PANI-Mn^(2+) and PANI-Cu^(2+) were studied by cyclic voltammetry(CV), impedance(EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs.

Review on transition metal compounds based counter electrode for dye-sensitized solar cells

Commercial application of the dye-sensitized solar cells（DSCs） depends on great improvement of the power conversion efficiency and reduction of the fabrication cost. Generally, developing low cost counter electrode catalysts to replace the expensive Pt counter electrode is a feasible path to reduce the production cost of DSCs. In this review article, we summarize the recent progress on the transition metal compound based counter electrode catalysts containing carbides, nitrides, oxides, sulfides, phosphide, selenides, borides, silicide, and telluride toward the regeneration of the traditional iodide redox couple.Moreover, the benefits and drawbacks of each kind of CE catalyst are discussed and the research directions to design new counter electrode catalysts in future research are also proposed.

Endoscopy-assisted purely total outer wall excision for pediatric Sylvian arachnoid cysts

Background To present a novel endoscopy-assisted surgical strategy of Sylvian arachnoid cysts(ACs).Case presentation Endoscopy-assisted surgery was performed on 9 children(May 2019-December 2021).All patients were evaluated with CT and/or MRI and had regular follow-up examinations.The procedure consisted of performing a small temporal craniotomy(2 cm)behind the hairline.After dural opening,the surgery was performed with the assistance of a rigid 30-degree transcranial endoscope,self-irrigating bipolar forceps,and other standard endoscopic instruments.Steps included total excision of the AC outer wall and dissection of arachnoid adhesion around the cystic edge to communicate the residual cyst cavity with subdural space.Compared with the microscopical procedure,a 30-degree transcranial endoscope provides a wider view,especially for the lateral part exposure of the outer wall.The average age of the patients was 27.7 months(range 13-44 months).The Sylvian AC was in the right hemisphere in three patients and six in the left,respectively.1 patient suffered transient postoperative epilepsy.There was no mortality or additional postoperative neurological deficit in this series.All of the patients achieved significant clinical improvement after surgery.Radiological examination after the operation showed a significant reduction in all cases(100%,9/9)and disappearance in one case(11.1%,1/9).Postoperative subdural fluid collection occurred in six cases and completely resolved spontaneously in 9 months.Conclusion The study demonstrated the minimally invasive,safety,and effectivity of the endoscopy-assisted purely total outer wall excision.

Synthesis of La_2MoO_6@MWCNTs composite catalysts as Pt-free counter electrodes for dye-sensitized solar cell

Pt-free counter electrode(CE) composed of La2 MoO(LaO-MoO) was successfully synthesized by simple pyrolysis of lanthanum acetate(CHOLa·xHO) and hexaammonium heptamolybdate tetrahydrate((NH4)6 MoO·4 HO). Furthermore,three proportions composites catalysts of La2 MoO@MWCNTs based on La2 MoOand multiwall carbon nanotubes(MWCNTs) were prepared and characterized as Ptfree catalyst for CE in dye-sensitized solar cells(DSSCs). The morphology and structure of La2 MoO@MWCNTs composites were determined by scanning electron microscopy, transmission electron microscope and X-ray diffraction. The electrochemical performance of La2 MoO@MWCNTs composite catalysts for CEs was determined by photocurrent-voltage measurements, cyclic voltammetry,electrochemical impedance spectroscopy, and Tafel polarization. The power conversion efficiencies of4.68%, 4.87% and 5.06% are obtained for La2 MoO:MWCNTs with the mass ratios of 5:1, 3:1 and 1:1 towards the reduction of I~-to I~-under the same conditions,respectively,which are superior to those of MWCNTs(3,94%) and La2 MoO(1.71%) electrodes. The experimental results reveal that the presence of MWCNTs results in an augmented active catalytic surface area and enhanced charge transfer from CE to the electrolyte.

A hydrophobic artificial solid-interphase-protective layer with fast self-healable capability for stable lithium metal anodes

Lithium(Li)metal has been considered as one of the most promising anodes for high-energy-density batteries.However,the hyperactivity of metallic Li and its dendrite growth are the major hurdles to its practical applications.Herein,a multi-functional solid-interphase-protective layer with excellent waterproof performance and fast self-healing properties was modified on the surface of Li metal to address the above issues.Under the protection of this interface,the metallic Li(denoted as P-Li)exhibited superior electrochemical stability in both Li/Li symmetric cells and full cells.Notably,even after being exposed to humid air for 3 h,the LiFePO_(4)||Li full battery with P-Li anodes still showed long-term stability with a transcendental capacity retention of~100% after 100 cycles,revealing a significant advantage to the non-working LiFePO_(4)||Li battery with air-exposed bare Li anodes.