Efficient Dual-Function Catalyst: Palladium–Copper Nanoparticles Immobilized on Co-Cr LDH for Seamless Aerobic Oxidation of Benzyl Alcohol and Nitrobenzene Reduction

Abstract

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 NaBH4 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−1). 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.

Keywords

• layered double hydroxides
• benzyl alcohol oxidation
• sol-immobilization method
• nitrobenzene reduction
• Pd-Cu NPs