导电油墨用镀银石墨粉的研制

将天然鳞片状石墨先进行化学镀铜、再化学镀银制得镀银石墨粉,通过扫描电镜观察了所制备的镀银石墨粉与直接镀银石墨粉及其球磨5h后的试样的表面形貌。将制备的样品用于印刷导电油墨,测试了镀银石墨粉的膜电阻率。结果表明,直接镀银的石墨表面镀层不均匀、覆盖率不高,球磨后银层发生大面积脱落;化学镀铜后再镀银的石墨粉镀层包覆程度高,晶粒尺寸均匀、致密,球磨后没有发生明显的镀层剥离现象。含该镀银石墨粉的导电油墨的膜电阻率为1.36×104·cm,导电性能达标。     

水化在18-冠醚-6对K+和Na+选择过程中作用的理论研究

A combination of molecular dynamics (MD) and density functional theory (DFT) calculations were used to study the hydration structures of K+ and Na+ ions under the confinement of 18-crown-6 in order to identify the role of water in the selectivity of 18-crown-6 towards K+. The radial distribution functions, coordination numbers, orientation structures and interaction energies were analyzed to investigate the hydration of K+ and Na+ in 18-crown-6/cation complexes. All calculations of K+ and Na+ in bulk water were also conducted for comparison. The simulation results show that the orientation distributions of the water molecules in the first coordination shell of K+ are more sensitive to the confinement of 18-crown-6 than those of Na+. It is more favorable to confine a K+ in 18-crown-6 than a Na+ in terms of interaction energy. Good agreement is obtained between MD results and DFT results.     

热处理对Pt纳米线电催化性能的影响

采用阳极氧化铝(AAO)模板法电化学沉积制备了Pt纳米线催化剂,并进行了热处理。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学测试对热处理前后Pt纳米线催化剂的晶体结构、形貌和电催化性能进行了表征,并与商业碳载铂(Pt/C)做对比。SEM照片表明制备了表面粗糙的Pt纳米线。循环伏安法(CV)和计时电流曲线表明,Pt纳米线较Pt/C催化活性高,退火后Pt纳米线更利于甲醇氧化,且稳定性更好。旋转圆盘电极(RDE)测试研究发现,未经热处理的Pt纳米线催化剂氧还原反应(ORR)极化曲线的半波电势相对Pt/C有正移,有更大的极限扩散电流,利于氧还原反应的发生。     

水化在18-冠醚-6对K+和Na+选择过程中作用的理论研究

A combination of molecular dynamics (MD) and density functional theory (DFT) calculations were used to study the hydration structures of K+ and Na+ ions under the confinement of 18-crown-6 in order to identify the role of water in the selectivity of 18-crown-6 towards K+. The radial distribution functions, coordination numbers, orientation structures and interaction energies were analyzed to investigate the hydration of K+ and Na+ in 18-crown-6/cation complexes. All calculations of K+ and Na+ in bulk water were also conducted for comparison.The simulation results show that the orientation distributions of the water molecules in the first coordination shell of K+ are more sensitive to the confinement of 18-crown-6 than those of Na+. It is more favorable to confine a K+ in 18-crown-6 than a Na+ in terms of interaction energy. Good agreement is obtained between MD results and DFT results.     

模板法制备CdSe纳米线及其光学性质的研究

利用恒电位沉积方法,在阳极氧化铝(AAO)模板里沉积了CdSe纳米线。对其进行了结构和光学性质的表征,并且用循环伏安法讨论了其沉积机理。结果表明:室温下,0.1 mol·L-1CdSO4+0.25 mol·L-1H2SO4+50 mmol·L-1 SeO2配比的溶液,0.4 V恒电位沉积,在AAO模板中制备出了CdSe纳米线。EDS的结果表明Cd和Se的化学计量比接近于1:1;通过XRD确定了所沉积的CdSe为面心立方结构,其择优取向为(111)晶面。紫外可见分光光度计吸收光谱表明其吸收范围在400~700 nm,吸收最大处在500 nm,PL发射谱表明CdSe纳米线的发光峰在400 nm左右。