Hydroxymethylfurfural oxidation over unsupported Pd-Au alloy catalysts prepared by pulsed laser ablation: Synergistic and compositional effects

Bimetallic nanoparticles are of high interest for electronics, photonics, biomedicine, and heterogeneous catalysis. To reveal the effects of structure and composition of bimetallic nanoparticles on catalytic properties, unsupported particles with clean surfaces and well-defined characteristics should be considered. Herein, colloidal Au, Pd, and Au-Pd catalysts prepared by pulsed laser ablation in liquid are studied in 5-hydroxymethylfurfural (HMF) oxidation. The catalysts are characterized by ELS, UV–vis spectroscopy, XRD, TEM, and SAED methods. The results show the formation of Au1−yPdy alloy particles that remain stable in pure water without the presence of any surfactant and feature higher performance towards formylfuran carboxylic and furandicarboxylic acids as compared with monometallic samples. The results indicate the combined benefits of Pd1−yAuy alloys in aerobic catalytic HMF oxidation due to a synergistic effect comprising the formation of Au-Pd interface in alloy nanoparticles, where the metals activate different moieties of HMF molecule

Ag/CeO2 Composites for Catalytic Abatement of CO, Soot and VOCs

Nowadays catalytic technologies are widely used to purify indoor and outdoor air from harmful compounds. Recently, Ag–CeO2 composites have found various applications in catalysis due to distinctive physical-chemical properties and relatively low costs as compared to those based on other noble metals. Currently, metal–support interaction is considered the key factor that determines high catalytic performance of silver–ceria composites. Despite thorough investigations, several questions remain debating. Among such issues, there are (1) morphology and size effects of both Ag and CeO2 particles, including their defective structure, (2) chemical and charge state of silver, (3) charge transfer between silver and ceria, (4) role of oxygen vacancies, (5) reducibility of support and the catalyst on the basis thereof. In this review, we consider recent advances and trends on the role of silver–ceria interactions in catalytic performance of Ag/CeO2 composites in low-temperature CO oxidation, soot oxidation, and volatile organic compounds (VOCs) abatement. Promising photo- and electrocatalytic applications of Ag/CeO2 composites are also discussed