Effect of NaBH4 on properties of nanoscale zero-valent iron and its catalytic activity for reduction of p-nitrophenol
Effect of NaBH4 on properties of nanoscale zero-valent iron and its catalytic activity for reduction of p-nitrophenol
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DOI：
10.1016/j.apcatb.2015.10.006
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发表时间：
2016-03-01
影响因子：
22.1
通讯作者：
Hanna, Khalil
中科院分区：
文献类型：
--
作者：
Bae, Sungjun;Gim, Suji;Hanna, Khalil
采用液相色谱、光谱（振动光谱和X射线光电子能谱）、固体分析（透射电镜和X射线衍射）和密度泛函理论（DFT）研究了纳米零价铁（NZVI）/NaBH 4体系在氧气环境中还原对硝基苯酚（p-NP）生成对氨基苯酚（p-AP）的反应.向NZVI悬浮液中加入NaBH 4显示NZVI（60-100 nm）的分解，由于最外表面的化学蚀刻（即，磁铁矿）。NZVI/NaBH_4催化剂循环使用4次后，p-NP完全还原，p-AP转化率高达98%以上，与贵金属催化剂相当。表面分析证实，NaBH 4可以阻止NZVI表面的氧化，导致p-NP在氧气环境中的持续还原。实验结果和DFT计算表明，不仅形成较小的NZVI，而且在NZVI的最外表面上还原p-NP的热力学偏好（即，磁铁矿）可能会显着影响NZVI/NaBH 4体系中p-NP的还原过程。这些新的发现可以促进新的NZVI技术的发展，可用于在氧气环境中的废水还原处理。(C)2015 Elsevier B. V.版权所有。
The reduction of p-nitrophenol (p-NP) to p-aminophenol (p-AP) by nanoscale zero-valent iron (NZVI)/NaBH4 system in an oxygen environment was studied by means of liquid chromatography, spectroscopy (vibration and X-ray photoelectron), solid analyses (transmission electron microscopy and X-ray diffraction) and density functional theory (DFT) calculations. Addition of NaBH4 into NZVI suspension showed the disintegration of NZVI (60-100 nm), resulting in the formation of much smaller particles (15-40 nm) due to the chemical etching of outermost surfaces (i.e., magnetite). Interestingly, complete reduction of p-NP and high conversion efficiency of p-AP (>98%) were observed in NZVI/NaBH4 system even after four recycling which is quite comparable with widely used noble metallic catalysts. Surface analysis confirmed that NaBH4 can prevent the oxidation of NZVI surface, leading to the continuous reduction of p-NP in oxygen environments. Experimental results and DFT calculations suggested that not only the formation of smaller NZVI but also thermodynamic preferences for reduction of p-NP on outermost surfaces of NZVI (i.e., magnetite) may significantly affect the reduction process of p-NP in NZVI/NaBH4 system. These novel findings can promote the development of new NZVI technologies which can be used for wastewater reductive treatment in oxygen environments. (C) 2015 Elsevier B.V. All rights reserved.