Nonenzymatic H2O2 Electrochemical Sensor Based on SnO2‐NPs Coated Polyethylenimine Functionalized Graphene

This paper demonstrated using polyethylenimine (PEI)‐functionalized graphene (Gr) incorporating tin oxide (SnO₂) hybrid nanocomposite as a platform for nonenzymatic H₂O₂ electrochemical sensor. The results of UV‐vis spectroscopy and X‐ray diffraction (XRD) confirmed the simultaneous formation of tin oxide (SnO₂) nanocomposite and reduction of graphene oxide (GO). Transmission electron microscopy (TEM) images showed a uniform distribution of nanometer‐sized tin oxide nanoparticles on the grapheme sheets, which could be achieved using stannous chloride (SnCl₂) complex instead of tin oxide as precursor. The electrochemical measurements, including cyclic voltammetry (CV) and amperometric performance (I‐t), showed that the PEI‐functionalized Gr supported SnO₂ (SnO₂‐PEI‐Gr) exhibited an excellent electrocatalytic activity toward the H₂O₂. The corresponding calibration curve of the current response showed a linear detection range of 9×10⁻⁶∼1.64×10⁻³ mol L⁻¹, while the limit of detection was estimated to be 1×10⁻⁶ mol L⁻¹. Electrochemical studies indicated that SnO₂ and functionalized Gr worked synergistically for the detection of H₂O₂.     

蒸氨法制备铜硅催化剂的二甲醚水蒸气重整制氢性能

采用蒸氨法制备出不同Cu负载量的xCu/SiO_2-AE催化剂,并将其用于二甲醚水蒸气重整制氢反应。当Cu负载量为30%(w)时,30Cu/SiO_2-AE催化剂表现出最佳的催化性能。结果显示,该方法制备的催化剂表面具有高度分散的CuO和层状硅酸铜物相,经还原后分别形成Cu~0和Cu~+物种。与常规浸渍法制备的30Cu/SiO_2-IM催化剂相比,蒸氨法制备的30Cu/SiO_2-AE催化剂具有优异的催化稳定性和活性,这与其独特的层状结构和表面Cu~0与Cu~+之间的协同作用相关。     

负载型双金属催化剂的制备及其等离子体催化氨分解制氢性能

利用等体积浸渍法制备了Fe-Co、Fe-Ni、Mo-Co、Mo-Ni双金属催化剂(总金属含量均为10%(w,质量分数),双金属摩尔比均为1:1),考察了其在等离子体条件下氨分解活性,结果表明Fe-Ni双金属催化剂表现出较好的协同作用。在此基础上,进一步考察了Fe/Ni摩尔比对其活性的影响。结果表明:当Fe/Ni摩尔比为6/4时,氨分解活性最好,而且该双金属催化剂稳定性良好。采用N_2物理吸附、X射线衍射(XRD)、H_2-程序升温还原(H_2-TPR)和高分辨透射电子显微镜(HRTEM)对催化剂的物化性质、还原性能、微观形貌等进行了研究。结果表明:活性较好的Fe-Ni双金属催化剂中,Fe与Ni形成尖晶石结构NiFe_2O_4,该结构有利于Fe和Ni的还原,即活性组分易恢复金属态,这可能是其活性较高的原因。     

无定型钼硫化物/还原氧化石墨烯的辐射合成及其电催化析氢性能

钼硫化物被认为是一种高效的电催化析氢反应的催化剂,因此其合成方法受到了广泛的研究和关注。本文以四硫代钼酸铵和氧化石墨为前驱体,利用γ射线对其辐照还原,一步法制备了钼硫化物/还原氧化石墨烯(Mo S_x/RGO)复合材料。通过X射线光电子能谱、X射线衍射、透射电子显微镜、Raman光谱等表征手段确认复合材料中的Mo Sx为无定型结构,且氧化石墨烯得到了有效的还原。同时系统研究了吸收剂量、前驱体配比对复合材料作为析氢反应催化剂性能的影响。结果发现,Mo Sx/RGO复合材料具有优异的催化性能,其催化起始电压为110 m V,在电流密度为10 m A·cm~(-2)时过电势仅为160 m V,Tafel斜率为46 m V·dec~(-1),说明该催化剂催化析氢机理为Volmer-Heyrovesy机理。此外,Mo Sx/RGO复合材料还具有良好的催化稳定性。     

由半刚性三羧酸配体构筑的一维和二维钴(Ⅱ)配位聚合物的合成、晶体结构及磁性质

采用水热方法,用半刚性三羧酸配体（H₃cpta）和菲咯啉（phen）或2,2''-联吡啶（2,2''-bipy）与CoCl₂·6H₂O反应,合成了一个一维链状配位聚合物[Co（μ2-Hcpta）（phen）（H₂O）]_n（1）和一个二维层状配位聚合物[Co₃（μ5-cpta）₂（2,2''-bipy）₂]_n（2）,并对其结构和磁性质进行了研究。结构分析结果表明2个配合物均属于单斜晶系,P2_1/c空间群。配合物1具有一维链状结构,而且这些一维链状结构通过C-H…O氢键作用进一步形成了二维超分子网络。而配合物2具有由三核钴单元构筑的二维层状结构。研究表明,配合物1和2中相邻钴离子间存在反铁磁相互作用。     

由联苯四羧酸配体构筑的一维锰(Ⅱ)和二维铜(Ⅱ)配位聚合物的合成、晶体结构及磁性质

采用水热方法,用2种联苯四羧酸配体（2,4-H₄bpta和3,5-H₄bpta）和4,4''-联吡啶（4,4''-bipy）或2,2''-联吡啶（2,2''-bipy）分别与MnCl₂·4H₂O和CuCl₂·H₂O反应,合成了一个具有一维双螺旋链结构的配位聚合物[Mn（μ₃-2,4-H₂bpta）（4,4''-bipy）₂]_n（1）和一个二维层状配位聚合物{[Cu（μ4-3,5-bpta）_0.5（2,2''-bipy）（H₂O）]·H₂O}_n（2）,并对其结构和磁性质进行了研究。结构分析结果表明2个配合物分别属于单斜晶系,P2₁/c和C2/c空间群。配合物1具有一维双螺旋链结构,而且这些一维链通过O-H…N氢键作用进一步形成了二维超分子网络。而配合物2具有二维层状结构。研究表明,配合物1中相邻锰离子间存在铁磁相互作用。     

Supramolecular architectures and crystal structures of gold(III) compounds with semicarbazones

The synthesis and crystal structures of two novel semicarbazones and four gold(III) compound derivatives of these semicarbazones are presented. A pattern in the formation of the semicarbazones shows the association of Cl^– ions held together by intra- and intermolecular forces. [AuCl₄]^? and [AuBr₄]^? anions are co-crystallised with these semicarbazone ligands, and the packing architectures revealed by a single-crystal X-ray diffraction analysis showed the different influences of the anions and the association of these chemical species by intermolecular forces on the crystal packing. Crystal engineering led to gold(III) compounds that are stabilised by relevant hydrogen bonding networks, which demonstrated their importance to the supramolecular organisation of the studied compounds. Interestingly, Cl???Br interactions are observed and contribute to the formation of the supramolecular structures. Elemental analysis data and spectroscopic properties in the solid state and solution are also described.