(中國科學(xué)院過程工程研究所， 北京 100080)
摘 要: 采用SEM、EDS、XRD等方法對(duì)TiO2直接電化學(xué)還原產(chǎn)物進(jìn)行分析，指出TiO2電極的還原是從外向內(nèi)由高價(jià)到低價(jià)再到金屬逐步進(jìn)行的。對(duì)還原過程中電流、還原氣相產(chǎn)物的分析結(jié)果表明：還原過程電流效率低，并且電流效率隨電解時(shí)間延續(xù)而降低，陽極產(chǎn)物CO、CO2與陰極中間產(chǎn)物Ca發(fā)生副反應(yīng)以及副反應(yīng)產(chǎn)物炭黑造成電流短路是電流效率低的主要原因。提高電流效率的途徑有兩條：一是增大陰、陽極間距，減小副反應(yīng)的發(fā)生；二是使電解池表面熔鹽不斷導(dǎo)出，或采取某一隔離措施，使副反應(yīng)產(chǎn)生的炭黑在陰、陽極之間不造成電流短路。
關(guān)鍵字: 電化學(xué)還原; 電流效率; TiO2
（ Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100080, China）
Abstract: The products of electrochemical reduction of TiO2 were examined by SEM, EDS and XRD. The results show that TiO2 is reduced step by step from outside to inside and from high valence oxide to low valence oxide until to metal. The analysis of current and anode gases during electrolysis indicates that the average current efficiency is low and decreases with electrolysis time. The secondary reactions between CO，CO2 and Ca evolved at cathode and short circuit caused by the produced black carbon are the main reasons resulting in low current efficiency. There are two ways to improve the current efficiency. First, the distance between the anode and cathode should be increased enough in order to limit the secondary reaction. Second, the molten salt at the surface should be drained continuously or the anode and cathode should be separated to prevent short circuit caused by black carbon.
Key words: electrochemical reduction; current efficiency; TiO2
