Ordabaeva Aigul T, Muldakhmetov Zainulla M, Kim Sergey V, Kasenova Shuga B, Sagintaeva Zhenisgul I, Gazaliev Arstan M
Institute of Organic Synthesis and Chemistry of Coal of Kazakhstan Republic, Alikhanov Str., 1, Karaganda 100000, Kazakhstan.
Laboratory of Thermochemical Processes, Zh. Abishev Chemical-Metallurgical Institute, Karaganda 100009, Kazakhstan.
Molecules. 2023 Sep 9;28(18):6545. doi: 10.3390/molecules28186545.
This paper studies the dependence of the specific heat capacity (C) of activated carbon obtained by the activation of coke fines on temperature (T, K) and the dependence of electrical resistance (, Om) on temperature (T, K). In the course of the work, it was found that in the temperature range of 298.15-448 K on the curve of dependence C - (T) at 323 K there is a jump in heat capacity, associated with a phase transition of the second kind. Measurements of the temperature dependence of electrical resistance on temperature were also carried out, which showed that activated carbon in the temperature range of 293-343 K exhibits metallic conductivity, turning into a semiconductor in the temperature range of 343-463 K. The calculation of the band gap showed that the resulting activated carbon is a semiconductor with a moderately narrow band gap. The satisfactory agreement of the phase transition temperatures on the curves of the temperature dependences of the heat capacity on temperature (323 K) and on the curves of the dependences of electrical resistance and the relative permittivity on temperature (343 K) indicates the nature of this phase transition, i.e., at a temperature of 323 K, the change in heat capacity is associated with the transition from semiconductor conductivity to metallic.
本文研究了由焦粉活化制得的活性炭的比热容（C）对温度（T，K）的依赖性以及电阻（，Ω）对温度（T，K）的依赖性。在研究过程中发现，在298.15 - 448 K的温度范围内，在C - （T）依赖性曲线上，323 K处的热容存在跳跃，这与第二类相变有关。还进行了电阻对温度的温度依赖性测量，结果表明，活性炭在293 - 343 K的温度范围内表现出金属导电性，在343 - 463 K的温度范围内转变为半导体。带隙计算表明，所得活性炭是一种带隙适中较窄的半导体。比热容对温度依赖性曲线（323 K）上的相变温度与电阻和相对介电常数对温度依赖性曲线（343 K）上的相变温度之间令人满意的一致性表明了该相变的性质，即，在323 K的温度下，热容的变化与从半导体导电性向金属导电性的转变有关。
