Novel hybrid materials with integrated catalytic properties and hydrophobic response, C@Fe–Al2O3 hybrid samples, were presented and tested as catalysts for phenol reaction in aqueous solutions at atmospheric pressure and mild temperature conditions, using CO2 as a feedstock. A series of carbon-coated γ-alumina pellets (C@Fe–Al2O3) were synthesized and characterized by TGA, Brunauer–Emmett–Teller (BET) method, Raman spectroscopy, SEM, TEM, and XPS in order to get comprehensive knowledge of their properties at the nanoscale and relate them with their catalytic behavior. The results obtained correlated their catalytic activities with their carbon surface compositions. The application of these materials as active catalysts in the Kolbe–Schmitt reaction for CO2 conversion in aqueous media was proposed as an alternative reaction for the valorization of exhausts industrial effluents. In these early tests, the highest conversion of phenol was observed for the hybrid samples with the highest graphitic characteristic and the most hydrophobic behavior. Carboxylation products such as benzoic acid, p-hydroxybenzoic acid, and salicylic acid, have been identified under these experimental conditions.

No abstract

Powder metallurgy technique has been extended in automobile industry and other engineering applications. Competitive manufacturing costs have led to important innovations in different fields of powder metallurgy. Recently, research has been focused on reaching higher performance at a lower cost. Carbon nanostructures as carbon nanofibres (CNF) have also entered in the material science as reinforcing composites. In this study, different materials formed by low alloy steel Fe-Ni-Mo powder (Distaloy AQ) with 0.4% of graphite and 0.5% CNFs (carbon nanofibres) synthesised at 723, 773, 823 and 873 K have been studied. All the materials were compacted at 700 MPa and sintered at 1393 K and 90N 2 -10H 2 atmosphere. The influence of CNFs synthesis temperature has been analysed for its application in powder metallurgy. The microstructure, mechanical properties such as tensile strength, elongation, hardness, density and wear behaviour were investigated. The CNFs synthesised at 873 K promoted better mechanical properties.