Synthesis of gold and palladium nanoparticles supported on CuO/rGO using imidazolium ionic liquid for CO oxidation

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

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.

Mn(III) Schiff base complexes containing crown ether rings immobilized onto MCM-41 matrix as heterogeneous catalysts for oxidation of alkenes

Six catalysts MnL¹-MnL⁶, containing two crown ether rings and their analogs supported on the MCM-41 heterogeneous substrate (MnL¹@MCM41-MnL⁵@MCM41) were synthesized and characterized. A mixture of molecular oxygen, as an oxidant, and these catalysts were used for the epoxidation of styrene. As a general result, the supported catalysts showed better performance compared with the unsupported analogs. On the other hand, the supported species, in addition to recyclability, did not require an axial base and reducing agent.

Neighboring sp-Hybridized Carbon Participated Molecular Oxygen Activation on the Interface of Sub-nanocluster CuO/Graphdiyne

Activation of O₂ is a crucial step in oxidation processes. Here, the concept of sp-hybridized C≡C triple bonds as an electron donor is adopted to develop highly active and stable catalysts for molecular oxygen activation. We demonstrate that the neighboring sp-hybridized C and Cu sites on the interface of the sub-nanocluster CuO/graphdiyne are the key structures to effectively modulate the O₂ activation process in the bridging adsorption mode. The as-prepared sub-nanocluster CuO/graphdiyne catalyst exhibited the highest CO oxidation activity and readily converted 50% CO at around 133 °C, which is 34 and 94 °C lower than that for CuO/graphene and CuO/active carbon catalysts, respectively. In situ diffused reflectance infrared Fourier transform spectroscopy and density functional theory calculation results proved that the neighboring sp-hybridized C is more favorable to promote the rapid dissociation of carbonate than sp²-hybridized C without overcoming any energy barrier. The gaseous CO directly reacts with the active molecular oxygen and tends to proceed through the E-R mechanism with a relatively low energy barrier (0.20 eV). This work revealed that sp-hybridized C of graphdiyne-based materials could effectively improve the O₂ activation efficiency, which could facilitate the low-temperature oxidation processes.

Facile design of a WO3 nanorod-decorated graphene oxide 1D–2D nanocatalyst for the synthesis of quinoline and its derivatives

Graphene oxide supported WO3 nanorod as an efficient and recyclable catalyst for synthesis of Quinoline and its derivatives under solventless condition.

Graphene-Based Composites as Catalysts for the Degradation of Pharmaceuticals

The incessant release of pharmaceuticals into the aquatic environment continues to be a subject of increasing concern. This is because of the growing demand for potable water sources and the potential health hazards which these pollutants pose to aquatic animals and humans. The inability of conventional water treatment systems to remove these compounds creates the need for new treatment systems in order to deal with these class of compounds. This review focuses on advanced oxidation processes that employ graphene-based composites as catalysts for the degradation of pharmaceuticals. These composites have been identified to possess enhanced catalytic activity due to increased surface area and reduced charge carrier recombination. The techniques employed in synthesizing these composites have been explored and five different advanced oxidation processes-direct degradation process, chemical oxidation process, photocatalysis, electrocatalyis processes and sonocatalytic/sono-photocatalytic processes-have been studied in terms of their enhanced catalytic activity. Finally, a comparative analysis of the processes that employ graphene-based composites was done in terms of process efficiency, reaction rate, mineralization efficiency and time required to achieve 90% degradation.