杂多酸修饰的电极对于甲醇电氧化的促进作用

采用杂多酸修饰光滑铂电极,研究其对甲醇电催化氧化的作用,发现与未修饰光滑铂电极相比,分别经磷钨酸和硅钨酸修饰的电极上甲醇电催化氧化速率明显增加.     

Electronic structures and thermodynamic stabilities of aluminum-based deuterides from first principles calculations

The alanates (complex aluminohydrides) have relatively high gravimetric hydrogen densities and are among the most promising solid-state hydrogen-storage materials. In this work, the electronic structures and the formation enthalpies of seven typical aluminum-based deuterides have been calculated by the plane-wave pseudopotential method, these being AlD₃, LiAlD₄, Li₃AlD₆, BaAlD₅, Ba₂AlD₇, LiMg(AlD₄)₃ and LiMgAlD₆. The results show that all these compounds are large band gap insulators at 0 K with estimated band gaps from 2.31 eV in AlD₃ to 4.96 eV in LiMg(AlD₄)₃. The band gaps are reduced when the coordination of Al varies from 4 to 6. Two peaks present in the valence bands are the common characteristics of aluminum-based deuterides containing AlD₄ subunits while three peaks are the common characteristics of those containing AlD₆ subunits. The electronic structures of these compounds are determined mainly by aluminum deuteride complexes (AlD₄ or AlD₆) and their mutual interactions. The predicted formation enthalpies are presented for the studied aluminum-based deuterides.     

Fractional Stokes–Einstein relation in TIP5P water at high temperatures

Fractional Stokes–Einstein relation described by D ～(τ/T)~ξ is observed in supercooled water, where D is the diffusion constant, τ the structural relaxation time, T the temperature, and the exponent ξ =τ~(-1). In this work, the Stokes–Einstein relation in TIP5 P water is examined at high temperatures within 400 K–800 K. Our results indicate that the fractional Stokes–Einstein relation is explicitly existent in TIP5P water at high temperatures, demonstrated by the two usually adopted variants of the Stokes–Einstein relation, D ～τ~(-1)τand D ～ T/τ, as well as by D ～ T/η, where η is the shear viscosity. Both D ～τ~(-1)τand D ～ T/τ are crossed at temperature T_x= 510 K. The D ～τ~(-1)τis in a fractional form as D ～τξwith ξ =-2.09 for T ≤ T_xand otherwise ξ =τ~(-1).25. The D ～ T/τ is valid with ξ =τ~(-1).01 for T ≤ T_xbut in a fractional form for T T_x. The Stokes–Einstein relation D ～ T/η is satisfied below T_x = 620 K but in a fractional form above T_x. We propose that the breakdown of D ～ T/η may result from the system entering into the super critical region, the fractional forms of D ～τ~(-1)τand D ～ T/τ are due to the disruption of the hydration shell and the local tetrahedral structure as well as the increase of the shear viscosity.     

固体聚合物电解质水电解进行h/d同位素分离

固体聚合物电解质;水电解;电催化剂;氢同位素;分离     

聚酰亚胺抗氚辐照性能

聚合物常用于氚系统的真空部分及热核聚变装置中氚的次级包装材料。为了使聚合物在氚辐照场中得到有效、合理的利用，了解因氚的辐照效应而引起聚合物微观结构及力学性能的变化是氚系统进行概念性设计前必须弄清的问题。选用聚酰亚胺为研究对象，在氚气氛中静态辐照一定时间后，通过测定聚酰亚胺力学性能及组织结构的变化来评价聚酰亚胺的抗氚辐照性能，为聚酰亚胺在氚辐照场中的实际应用提供实验依据。     

氕和氘在Pd-8％Y合金管中的渗透性能

20世纪80年代，Wileman等提出了用钯合金膜分离氢同位素的设想。罗德礼等对一系列钯合金膜的氢同位素分离效应进行了研究，进一步证实了钯合金膜用于氢同位素分离的可行性。钯钇合金膜与其它合金膜相比，具有更好的氢同位素分离能力，采用PdY的原子数分数8％合金管作为分离膜，设计了钯合金膜分离器，初步的实验结果和理论估算表明该分离器完全适合大规模应用的需要。     

Mg2NiQ6（Q=H，D，T）体系的热力学氢同位素效应

为研究Mg2NiQ4(Q=H,D,T)体系的热力学氢同位素效应,基于量子力学第一原理,采用密度泛函与赝势平面波相结合的方法,计算了Mg2NiQ6(Q=H,D,T)体系的声子色散谱,利用声子色散谱得到了热力学函数.利用文献报道的氢同位素气体分子的热力学数据,采用热力学方法分析了Mg2Ni吸氢形成Mg2NiQ6的同位素效应.研究结果表明,Mg2Ni吸氢的同位素效应主要是原子相对振动的频率不同导致的.CaF2结构的Mg2NiQ6的氢同位素效应随温度升高由负同位素效应转变为正同位素效应.     

Mg2NiQ6(Q=H,D, T)体系的热力学氢同位素效应

为研究Mg2NiQ4(Q=H, D, T)体系的热力学氢同位素效应, 基于量子力学第一原理, 采用密度泛函与赝势平面波相结合的方法, 计算了Mg2NiQ6(Q=H, D, T)体系的声子色散谱, 利用声子色散谱得到了热力学函数. 利用文献报道的氢同位素气体分子的热力学数据, 采用热力学方法分析了Mg2Ni吸氢形成Mg2NiQ6的同位素效应. 研究结果表明, Mg2Ni吸氢的同位素效应主要是原子相对振动的频率不同导致的. CaF2结构的Mg2NiQ6的氢同位素效应随温度升高由负同位素效应转变为正同位素效应.     

LaNi4.7Al0.3Dx去氘化热、质传输二维模型研究

建立了LaNi4.7Al0.3Dx去氚化过程中热，质传输的二维数学模型。该模型考虑了气相和固相之间存在的温差以及氚化的密度和比热的变化。计算了金属氚化的在去氚化过程中气－固相温差，组分和密度的分布，以及热导率和加热流体温度对气－固相温差的影响，并考察了模型的适用性。计算结果表明：热导率及加热流体温度对气－固相温差影响显著，最大温差随热导率的增加而减小，随加热流体温度的升高而增大；金属氚化物中组分和密度的分布与气－固相温差有关；根据数学模型获得的反应分数与实验值具有很好的一致性。     

Sm3+对甲醇电化学氧化反应的助催化作用

分别以相同面积的光滑Pt电极和吸附了Sm3+的铂电极作为工作电极,在酸性介质中采用循环伏安法对甲醇氧化进行测定.结果表明,吸附了Sm3+的Pt电极上产生了更大的氧化电流,表明Sm3+的加入对甲醇的电催化氧化起到了促进作用.这一研究结果在直接甲醇燃料电池(DMFC)阳极催化剂研制方面具有较大的应用潜力.