Ag/MoS_2复合材料的原位反应合成热力学分析

Thermodynamic Analysis of In-situ Reaction Synthesis for Ag/Mo S_2 Composite Materials

通过对Ag/MoS_2复合材料的热力学计算与分析,探讨了采用原位反应合成Ag/MoS_2复合材料的可行性。结果表明,在同一温度条件下,s与Ag、Mo反应生成Ag_2S和MoS_2的标准自由焓低于Mo与Ag_2S反应生成Ag和MoS_2的标准自由焓,且生成的MoS_2的标准自由焓最低,即从热力学角度说明Mo能够将Ag_2S中的Ag置换出来;但是从Mo与Ag_2S反应生成Ag和MoS_2的标准自由焓来看,其标准自由焓高于s与Ag反应生成Ag_2S的标准自由焓,说明若采用原位反应合成技术制备Ag/MoS_2复合材料,将有部分Ag_2S存在于复合材料中,不能获得完全的Ag/MoS_2复合材料;因此,采用原位反应合成技术来制备完全的Ag/MoS_2复合材料是不可行的。从热力学的标准自由焓与温度的关系图发现,3种化学反应中的相变能够促进反应的进行。

The feasibility of in-situ reaction synthesis for Ag/MoS2 composites is discussed through thermodynamics calculation and analysis of silver molybdenum sulfide composite （Ag/MoS2）. The results show that, at the same temperature, standard free enthalpy of S reacts with Ag or Mo to generate Ag2S or MoS2 is lower than Mo reacts with Ag2S to generate Ag and MoS2, and the standard free enthalpy of generating MoS2 is the lowest one. Thermodynamically, Ag could be replaced by Mo from Ag2S. However, the standard free enthalpy of Mo reacts with Ag2S to generate Ag and MoS2 is higher than that S reacts with Ag to generate Ag2S. This indicates that if using in-situ reaction synthesis technology to prepare Ag/MoS2 composites, there will be a part of Ag2S exist in the composites. Therefore, using in-situ reaction synthesis technology to prepare complete Ag/MoS2 composite is not feasible. From the relationship between the standard free enthalpy and temperature, we find that the phase transition of these chemical reactions can promote the reaction.