累托石负载纳米金催化剂的制备及性能研究

项目名称： 累托石负载纳米金催化剂的制备及性能研究

项目编号： No.51462009

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 郑鹏武

作者单位： 江西科技师范大学

项目金额： 47万元

中文摘要： 纳米金属催化剂在石油化工、燃料电池、汽车尾气净化等领域广泛应用，但存在回收困难、因易团聚而导致催化效率低等问题。本项目以层状累托石（REC）为纳米金属催化剂载体。为提高REC比表面积，用壳聚糖（或季铵化壳聚糖）改性扩大其层间距。为便于催化剂回收，方法一是将REC表面多糖成分炭化还原镍离子形成磁性REC，再用酸化壳聚糖改性并还原氯金酸，制得纳米金负载磁性REC；方法二是用凝胶冷冻干燥方法制备超轻多孔纳米金负载REC整体型凝胶，将二维载体转变为三维多孔凝胶载体，并同时提高催化效率。改性REC表面附着的多糖羟基可以与金属离子形成相互作用，防止纳米催化剂团聚，提高分散性和催化效率。采用模型反应评价纳米金负载磁性REC和REC整体型凝胶的催化性能以及循环催化性能。本项目可为高分散纳米金属催化剂载体研究奠定基础，也可为纳米金属催化剂回收、催化效率提高以及扩展其催化领域的应用提供科学依据。

中文关键词： 累托石；纳米金；壳聚糖

英文摘要： Metal nanoparticles are widely used as the catalysts in the field of petrochemical, fuel cell, purification of exhaust gas and so on, but they have some defects such as difficult recovery and low catalytic efficiency due to the aggregation. In this project, rectories (RECs) are designed as the support of Au nanoparticles. Chitosan (or quaternized chitosan) is used to intercalate/ exfoliate REC layers to improve the specific surface area. Two methods are used to recycle catalysts. In the first method, chitosan are calcinated and changed into carbon layers on Ni nanoparticles to improve magnetic stability.The magnetic RECs are modified with acidified chitosan, and reduced HAuCl4 to Au noaoparticles on REC. In second methods, REC gels with porous 3D networks are fabricated using a simple process of aqueous gel precursor freezing, solvent exchange, and ethanol drying, where the two-dimensional REC layers are transformed into a three-dimensional porous gel supports to improve the catalytic efficiency. Since the hydroxyl groups of polysaccharide can form the interaction with metal ions, and prevent from the aggregates of metal nanoparticles, the dispersion and catalytic efficiency are improved.Two model reactions (the reduction of 4-nitrophenol and Suzukie-Miyaura coupling reaction) are used to assess the catalytic activity, stability and efficiency of (REC, modified REC, REC gels) supported Au catalysts. The project will provide a scientific basis for the study of metal nanoparticle supports with high disperdion as well as the applications on the recycle and efficient improvement of metal catalysts.

英文关键词： Rectorite;Au nanoparticles;chitosan