钯催化H_(2)O_(2)分解的机制探讨  

Mechanism of H_(2)O_(2) Decomposition Catalyzed by Palladium

作　　者：周小毛 杨淼 欧阳应根[1] 崔大庆 ZHOU Xiao-mao;YANG Miao;OUYANG Ying-gen;CUI Da-qing(China Institute of Atomic Energy,P.O.Box 275(93),Beijing 102413,China;School of Chemistry,Chemical Engineering and Life Sciences,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413 [2]武汉理工大学化学化工与生命科学学院,湖北武汉430070

出　　处：《核化学与放射化学》2021年第6期473-481,I0003,共10页Journal of Nuclear and Radiochemistry

摘　　要：高放废物(HLW)处置库近场地下水的辐解能够产生H_(2)O_(2),其被裂变产物合金颗粒(ε-颗粒)的催化分解属于多相表界面反应。本工作选用钯粉模拟ε-颗粒,采用高压反应釜研究体系总压和H_(2)分压对反应的影响,并按一级动力学模型拟合实验数据。添加HO·的捕获剂和淬灭剂的实验证明无H_(2)反应过程中存在HO·的生成步骤。钯的催化活性及形态变化与反应时间的关系表明,产物氧吸附在钯的表面对反应具有毒化作用。通过持续监测滤液中H_(2)O_(2)浓度的变化,发现溶液中存在类似于Haber-Weiss的反应持续消耗H_(2)O_(2)。推导出钯对H_(2)O_(2)分解的机制过程和影响因素,为处置库的安全评估提供基础数据。The radiolysis of near-field groundwater in high-level radioactive waste(HLW)repository will produce H_(2)O_(2)which is catalytically decomposed by fission product alloy particles(ε-particle)belongs to the surface interface process.In this work,palladium powder was used to simulateε-particles.The effects of total pressure and partial pressure of hydrogen on H_(2)O_(2)decomposition reaction were studied by autoclave experiments.The reaction rate constant is derived by the first-order kinetic model fitting.The formation of detectable HO·in the reaction process without hydrogen was proved by experiments with adding capture agent and quencher of HO·.The catalytic activity and morphological changes of palladium particles as a function of time were investigated.It is inferred that the product oxygen adsorbed on the surface of palladium has toxic effect.By continuously monitoring the change of H_(2)O_(2)concentration in the filtrate,it was detected that the decomposition of H_(2)O_(2)in the filtrate is similar to Haber-Weiss reaction in reaction process.The influence mechanism of palladium particles on the decomposition of H_(2)O_(2)is deduced,and the results of this work can provide significant reference data for the safety assessment of the repository.

关 键 词：钯 H_(2)O_(2) 催化分解 地质处置 界面化学反应 

分 类 号：TL942.1[核科学技术—辐射防护及环境保护]