碱式铜盐包覆Cu2O催化剂的形成机理及催化性能

采用铜盐与四种碱NaOH、Na2CO3、Na2SO3、Na2S2O3在室温(25℃)下反应于Cu2O表面包覆碱式铜盐，均得到组成为Cu2O@Cu4(SO4)(OH)6的核壳型催化剂，其中，由Na2S2O3得到的样品其催化活性远高于其他碱制备样品。通过性质表征可知，由Na2S2O3制得样品具有核内部孔洞多、缺陷分布广、活性表面大、表面粗糙、晶体紧实度低等特点，这些特征均有利于催化活性的提高。进一步研究确认，Na2S2O3在反应中具有多重身份，一是水解提供OH-；二是自身发生歧化反应或者与Cu2+发生氧化还原反应，生成SO42-和S2-，提供形成Cu4(SO4)(OH)6所需的SO42-；三是能与Cu2O核反应，使其溶解形成孔洞。因此，采用铜盐与Na2S2O3在室温下反应形成的Cu2O@Cu4(SO4)(OH)6核壳型催化剂具有非常高的催化活性，能实现黑暗条件下高效降解高浓度(400 mg/L)染料(橙黄II)，2h基本实现完全降解(99.5%)。

Study on the formation mechanism and catalytic performance of Cu2O coated basic copper salt core-shell catalyst

The core-shell catalysts which have the same composition of Cu2O@Cu4(SO4)(OH)6 were synthesized by the reaction at room temperature(25℃) of copper salts with four kinds of alkalis, include NaOH, Na2CO3, Na2SO3 and Na2S2O3. Thereinto, the sample prepared by Na2S2O3 exhibits the highest catalytic activity. The research results show that the sample prepared by Na2S2O3 possesses many holes and defects in the interior of core, large surface area, rough surface and low crystal compactness, which are beneficial to increase the catalytic activity. There are multiple identities of Na2S2O3 in the reaction. Firstly, Na2S2O3 hydrolyzes to provide OH- group, then disproportionate or react with Cu2+ ion by redox to produce SO42- and S2- ions, which provides SO42- to form Cu4(SO4)(OH)6 crystal. Besides, Na2S2O3 can react with Cu2O core, resulting in the generation of holes in the interior of Cu2O. Hence, the core-shell catalyst which has the composition of Cu2O@Cu4(SO4)(OH)6 and synthesized by Na2S2O3 at room temperature shows very high catalytic activity. It can almost completely degrade high concentration(400 mg/L) of dye(AO7) in the dark in 2h.