Hydrodeoxygenation of phenol on bifunctional Ni-based catalysts: Effects of Mo promotion and support

Hydrodeoxygenation (HDO) of phenol dissolved in decalin was studied over H-activated Ni and Mo-Ni catalysts supported on alumina and amorphous silica alumina (ASA) in the context of the O-removal from bio-liquids. The activity test was carried out in a flow reactor at 310 °C and total hydrogen pressure of 3 MPa. The catalyst samples were characterized by several physico-chemical techniques (S, H-TPR, HRTEM, DRIFT spectroscopy of adsorbed CO and NH, Raman spectroscopy, XPS, SEM-EDS and HRTEM) in order to obtain catalyst activity-structure correlation. After 4 h on stream, the Mo-Ni/ASA catalyst displayed the highest activity in the HDO of phenol, which was linked with its highest Ni dispersion, the Mo promoting action and largest acidity. The Mo-Ni/ASA catalyst displayed 2 times higher yield of O-free products than a commercial NiMoP(S)/AlO catalyst activated by sulfidation. The role of metals and metal oxides species in HDO reaction has been discussed.The authors express their gratitude to Drs. P. Castaño and R. Palos Urrutia (University of the Basque Country UPV/EHU, Spain) for their contribution to the GC/MS analysis and to Drs. L. Pascual and M. Capel(ICP-CSIC, Spain, for their HRTEM measurements. Economic supportfrom Comunidad de Madrid (Project CAM S2013/MAE-2882) is grate-fully acknowledge

Solar and visible light photocatalytic enhancement of halloysite nanotubes/g-C3N4 heteroarchitectures

Novel heteroarchitectures made of graphitic carbon nitride (g-C3N4) and halloysite nanotubes (HNTs) were prepared by a facile and soft self-assembly strategy. The morphological, structural and electronic properties of the HNTs/g-C3N4 nanocomposites were determined by means of a plethora of techniques including N-2 physisorption, XRD, FT-IR, TEM, UV-Vis absorption, XPS, zeta potential and photoluminescence (PL). Their photocatalytic activity was evaluated under both simulated solar light and pure visible light irradiation against the photodegradation of neutral, positively and negatively charged pollutants, namely phenol, methylene blue (MB) and methyl orange (MO), respectively. The prepared HNTs/g-C3N4 nanocomposites were proven to be durable and significantly more efficient than the pure g-C3N4 reference for the degradation of positively charged and neutral organics. The nanocomposites presented increased charge carrier formation and reduced recombination rates due to the tight contact between the two components. The enhanced photoactivity was attributed to the dual function of HNTs enhancing (a) the abundance and stability of the photogenerated e(-) and h(+) pairs and (b) the adsorption of positively charged organics on the nanocomposite. Both functions originate from the charged surface of HNTs