Effects of chemical etching and reduction activation of CeO2 nanorods supported ruthenium catalysts on CO oxidation

Ultrasonically assisted surface modified CeO2 nanospindle catalysts for conversion of CO2 and methanol to DMC

This study developed a facile and effective approach to engineer the surface properties of cerium oxide (CeO₂) nanospindle catalysts for the direct synthesis of dimethyl carbonate (DMC) from CO₂ and methanol. CeO₂ nanospindles were first prepared by a simple precipitation method followed by wet chemical redox etching with sodium borohydride (NaBH₄) under high intensity ultrasonication (ultrasonic horn, 20 kHz, 150 W/cm²). The ultrasonically assisted surface modification of the CeO₂ nanospindles in NaBH₄ led to particle collisions and surface reduction that resulted in an increase in the number of surface-active sites of exposed Ce³⁺ and oxygen vacancies. The surface modified CeO₂ nanospindles showed an improvement of catalytic activity for DMC formation, yielding 17.90 mmol·g_cat^-1 with 100 % DMC selectivity. This study offers a simple and effective method to modify a CeO₂ surface, and it can further be applied for other chemical activities.

Review of the Design of Ruthenium-Based Nanomaterials and Their Sensing Applications in Electrochemistry

In this review, ruthenium nanoparticles (Ru NPs)-based functional nanomaterials have attractive electrocatalytic characteristics and they offer considerable potential in a number of fields. Ru-based binary or multimetallic NPs are widely utilized for electrode modification because of their unique electrocatalytic properties, enhanced surface-area-to-volume ratio, and synergistic effect between two metals provides as an effective improved electrode sensor. This perspective review suggests the current research and development of Ru-based nanomaterials as a platform for electrochemical (EC) sensing of harmful substances, biomolecules, insecticides, pharmaceuticals, and environmental pollutants. The advantages and limitations of mono-, bi-, and multimetallic Ru-based nanocomposites for EC sensors are discussed. Besides, the relevant EC properties and analyte sensing approaches are also presented. On the basis of these insights, we highlighted recent results for synthesizing techniques and EC environmental pollutant sensors from the perspectives of diverse supports, including graphene, carbon nanotubes, silica, semiconductors, metal sulfides, and polymers. Finally, this work overviews the modern improvements in the utilization of Ru-based nanocomposites on the basis for electroanalytical sensors as well as suggestions for the field's future development.