基于氨基化煤基碳点的复合光催化剂的制备及对CO2还原的催化性能

采用过氧化氢氧化法剥离出煤炭结构中的晶体碳[煤基碳点(CDs)], 并通过亚硫酰氯氯化及乙二胺钝化等步骤对其进行氨基化修饰, 制得N, S共掺杂的氨基化煤基碳点(NH₂-CDs), 再利用其表面的氨基和含氧基等官能团的配位及分散作用, 将由氯化铜原位还原得到的氧化亚铜(Cu₂O)纳米粒子包覆于其中, 制备了复合催化剂Cu₂O/NH₂-CDs, 表征了其结构和形貌, 并考察了其可见光催化还原CO₂/H₂O的性能. 结果发现, NH₂-CDs的存在使复合催化剂不仅具备了较强的CO₂吸附性能, 而且还具有了高效的电子-空穴对分离和电子转移能力, 从而表现出优异的光催化还原CO₂制备HCOOH的性能. 反应6 h时, 产物HCOOH的量为2582.4 μmol/g cat, 约为同条件下纯Cu₂O作为光催化剂时产物HCOOH产率的7.3倍.

Preparation and CO2 Reduction Performance of Composite Photocatalyst Based on Aminated Coal-based Carbon Dots†

The crystalline carbon in the coal structure[coal-based carbon dots(CDs)] was stripped by hydrogen peroxide oxidation method, and then the surface of the synthesized carbon dots was modified by thionyl chloride chlorination, ethylenediamine passivation steps to obtain N, S co-doped aminated coal-based carbon dots(NH₂-CDs). After that, using the coordination and dispersing function of amino groups and oxygen-containing functional groups on the surface, a kind of composite photocatalyst, Cu₂O/NH₂-CDs, was prepared by coating cuprous oxide(Cu₂O) nanoparticles, which were obtained by in situ reduction of copper chloride(CuCl₂∙2H₂O), on the NH₂-CDs. The structures of the Cu₂O/NH₂-CDs were characterized and the photocatalytic performance toward CO₂ reduction under visible light was tested. The results show that the presence of NH₂-CDs not only makes the composite catalyst possess excellent CO₂ adsorption performance, but also improve the efficient electron-hole pair separation and electron transfer ability of the composite catalysts, so that Cu₂O/NH₂-CDs show excellent CO₂ photocatalytic reduction to HCOOH performance. After reaction for 6 h, the amount of HCOOH was up to 2582.4 μmol/g cat, about 7.3 times of that on Cu₂O photocatalyst under the same conditions.