Alzarea Linah A, Alhumaimess Mosaed S, Alsohaimi Ibrahim Hotan, Hassan Hassan M A, El-Aassar M R, Essawy Amr A, Kalil Haitham
Department of Chemistry, College of Science, Jouf University, Sakaka 2014, Saudi Arabia.
Chemistry Department, Cleveland State University, Cleveland, OH 44115, USA.
Nanomaterials (Basel). 2023 Jun 27;13(13):1956. doi: 10.3390/nano13131956.
Layered double hydroxides (LDHs) present exciting possibilities across various industries, ranging from catalytic applications to water remediation. By immobilizing nanoparticles, LDHs' characteristics and functionality can be enhanced, allowing for synergetic interactions that further expand their potential uses. A simple chemical method was developed to produce well-dispersed Pd-Cu NPs on a Co-Cr LDH support using a combination of in situ coprecipitation/hydrothermal and sol-immobilization techniques. The Pd-Cu@Co-Cr LDH catalysts was obtained, showing its catalytic activity in promoting the aerobic oxidation of alcohols and enabling the reduction of nitro-compounds through NaBH mediation. The physicochemical properties of the prepared catalyst were comprehensively investigated utilizing a range of analytical techniques, comprising FTIR, XRD, XPS, TGA, nitrogen adsorption isotherm, FESEM, and HRTEM-EDX. The findings showed the significance of immobilizing the bimetallic Pd-Cu nanoparticles on the Co-Cr LDH via an exceptional performance in the aerobic oxidation of benzyl alcohol (16% conversion, 99.9% selectivity to benzaldehyde) and the reduction of nitrobenzene (98.2% conversion, rate constant of 0.0921 min). The improved catalytic efficacy in benzyl alcohol oxidation and nitrobenzene reduction on the Pd-Cu@Co-Cr LDH catalyst is attributed to the uniform distribution and small size of the Pd-Cu NPs as active sites on the Co-Cr LDH surface. The prepared catalyst demonstrated exceptional stability during repeated runs. This study paves the way for multiple opportunities in tailoring, producing, and precisely controlling catalysts for various organic transformation reactions.
层状双氢氧化物(LDHs)在从催化应用到水修复等各个行业展现出令人兴奋的可能性。通过固定纳米颗粒,可以增强LDHs的特性和功能,从而实现协同相互作用,进一步扩大其潜在用途。开发了一种简单的化学方法,使用原位共沉淀/水热法和溶胶固定技术相结合,在Co-Cr LDH载体上制备出分散良好的Pd-Cu纳米颗粒。获得了Pd-Cu@Co-Cr LDH催化剂,该催化剂在促进醇的有氧氧化以及通过硼氢化钠介导实现硝基化合物还原方面表现出催化活性。利用一系列分析技术,包括傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、X射线光电子能谱(XPS)、热重分析(TGA)、氮吸附等温线、场发射扫描电子显微镜(FESEM)和高分辨率透射电子显微镜-能谱分析(HRTEM-EDX),对制备的催化剂的物理化学性质进行了全面研究。研究结果表明,通过在苯甲醇的有氧氧化(转化率16%,对苯甲醛的选择性99.9%)和硝基苯的还原(转化率98.2%,速率常数0.0921 min)方面的优异性能,将双金属Pd-Cu纳米颗粒固定在Co-Cr LDH上具有重要意义。Pd-Cu@Co-Cr LDH催化剂在苯甲醇氧化和硝基苯还原方面提高的催化效率归因于Co-Cr LDH表面作为活性位点的Pd-Cu纳米颗粒的均匀分布和小尺寸。制备的催化剂在重复运行过程中表现出优异的稳定性。这项研究为定制、生产和精确控制用于各种有机转化反应的催化剂创造了多种机会。