低密度负载型NiCoP催化剂的可控合成与性能研究

A low density supported composite catalyst NiCoP:synthesis and application

通过种子诱导合金化方法合成了低密度磁性非贵金属复合催化剂LDHMs@NiCoP,将磁性NiCoP三元合金纳米颗粒负载于低密度中空微球(LDHMs)载体上,既利用载体的大表面空间分隔效应阻止了纳米颗粒的团聚,又实现了集磁性分离、漂浮分离、大颗粒过滤分离等多种分离回收方式于一体的多种分离途径,而且通过非金属与非贵金属的合金化实现了非贵金属催化性能的提升。此外,本文研究发现Co/Ni比例(摩尔比)能够通过控制相应金属离子的浓度方便地进行调节,并进而实现LDHMs@NiCoP复合催化剂催化活性的有效调控。当Co/Ni摩尔比为0.96∶1时,LDHMs@NiCoP-0.96:1催化有机污染物—对硝基苯酚(4-NP)向药物中间体—对氨基苯酚(4-AP)的氢化转化表观速率k A可达33.5×10^-3 s^-1,归一化速率常数k N达15.6 s^-1 g^-1,比相同条件下合成的无载体NiCoP颗粒的表观速率常数k A提高3个数量级。本文探究的负载方式和合金化方法为优化非贵金属催化剂的催化性能提供了新思路,同时也可为其他新型负载型催化剂的设计和性能调控提供有益的参考和借鉴。

In this paper,low-density magnetic non-precious metal composite catalyst LDHMs@NiCoP was synthesized by seed-induced alloying method,and magnetic NiCoP ternary alloy nanoparticles were supported on low-density hollow microspheres(LDHMs),which not only utilized the large surface space separation effect of the carrier to prevent the agglomeration of the nanoparticles,but also realized a plurality of separation and recovery methods such as magnetic separation,floating separation,and large particle filtration separation.Furthermore,the catalytic performance of the non-precious metal was improved by alloying non-metals with non-precious metals.In addition,it was found that the Co/Ni ratio could be adjusted by controlling the feed ratio,which had a great influence on the catalytic performance of the LDHMs@NiCoP composite catalyst.When the Co/Ni ratio was 0.96∶1,the apparent rate k A of LDHMs@NiCoP catalyzed organic pollutants-p-nitrophenol(4-NP)to the pharmaceutical intermediate-p-aminophenol(4-AP)was 33.5×10^-3·s^-1,the normalized rate constant k N was 15.6 s^-1·g^-1,and k A was three orders of magnitude higher than that of pure NiCoP without LDHMs.The methods of loading and alloying optimization of non-precious metal catalytic properties explored in this paper provided a basis for preventing nanoparticle agglomeration and non-precious metal substitution of precious metal catalysts.