Role of Mo in catalysts based on noble metals in hydrodeoxygenation reactions

Oviedo, 26 – 28 Junio 2017 Role of Mo in catalysts based on noble metals in hydrodeoxygenation reactions D. Ballesteros-Plata, A. Infantes Castellón Departamento de Química Inorgánica, Cristalografía y Mineralogía (Unidad Asociada al ICP Universidad de Málaga, Campus de Teatinos, 29071 Málaga (Spain) Corresponding author: * ainfantes@uma 1. Introduction The use of bioenergy as a renewable alternative to fossil fuels is nowadays attracting more and more attention. The biofuel from biomass seem renewable resource that could contribute to sustainable development and glo preservation and it appears to have si which gives undesirable properties for combustion. To remove oxygen, catalytic hydrodeoxygenation (HDO) reactions are carried out. Mon ometallic Mo/Si, Pt/Si as well as bimetallic PtMo/Si catalysts were prepared and evaluated in the hydrodeoxygenation (HDO) biomass derived bio-oil. 2. Experimental In this study, a bimetallic PtMo catalyst ratio equal to 1 was prepared by incipient wetness impregnation monometallic samples, with a total metallic loading of 1%wt synergism between both phases . techniques (XRD; H 2 -TPR, N 2 physisorption, NH texture and acidic properties , as well as tests, 0.25 g of fresh catalysts (particle size 0.85 activity was measured on DBF at 275 °C organic feed flow 0.18 mL·min -1 . 3. Results and discussion The BET surface area values of the monometallic samples do not differ considerably compared to the bimetallic one (Table 1). Th e bare support isotherm is of macroporosity. The supported catalysts underwent an increase of N than 0.8, indicating the presence of pores of larger diameter. The increase in volume is due to the fact that the active phase is mainly deposited in the interparticular voids of fume silica MoO 3 diffraction peaks in the case of monometallic Mo/Si sample while no peak of Pt/Si one. For PtMo/Si, the presence of tiny diffraction peaks due to the presence of observed. These results show that in the bimetallic sample Mo is agglomerated if com pared to monometallic sample. If Mo noticeably changes under the presence of Pt. Thus, the TPR profile of Mo/Si sample shows a broad reduction profile with a hydrogen consumption Catálisis para un mundo más sosten Role of Mo in catalysts based on noble metals in hydrodeoxygenation reactions A. Infantes -Molina*, E. Rodríguez-Aguado, P. Braos - Departamento de Química Inorgánica, Cristalografía y Mineralogía (Unidad Asociada al ICP - Universidad de Málaga, Campus de Teatinos, 29071 Málaga (Spain) . ainfantes@uma .es energy as a renewable alternative to fossil fuels is nowadays attracting more and more fuel from biomass seem s to be a potential energy substitute for fossil fuels since it is a renewable resource that could contribute to sustainable development and glo and it appears to have si gnificant economic potential 1 . The problem is its high oxygen content, properties for combustion. To remove oxygen, catalytic hydrodeoxygenation (HDO) ometallic Mo/Si, Pt/Si as well as bimetallic PtMo/Si catalysts were prepared evaluated in the hydrodeoxygenation (HDO) reaction of dibenzofurane (DBF) In this study, a bimetallic PtMo catalyst supported on silica containing 2 wt% of metal by incipient wetness impregnation method . Moreover, with a total metallic loading of 1%wt , were also synthesized in order to evaluate the . The prepared catalysts were characterized by different experimental physisorption, NH 3 -TPD, TEM and XPS) in order to understand its structure, , as well as , to correlate catalyst structurecatalytic activity. tests, 0.25 g of fresh catalysts (particle size 0.85 –1.00 mm ) were used, diluted with SiC to 3 cm activity was measured on DBF at 275 °C and 1.5 MPa of H 2 ; the H 2 flow rate was 30 mL·min of the monometallic samples do not differ considerably compared to the e bare support isotherm is of type II , characteristic of materials with meso and macroporosity. The supported catalysts underwent an increase of N 2 adsorbed at relative pressures higher than 0.8, indicating the presence of pores of larger diameter. The increase in volume is due to the fact that the active phase is mainly deposited in the interparticular voids of fume silica 2 . XRD diffraction peaks in the case of monometallic Mo/Si sample while no peak was evidenced in the case the presence of tiny diffraction peaks due to the presence of These results show that in the bimetallic sample Mo is dispersed and instead Pt is more pared to monometallic sample. If TPR and TPD data are considered, the behavior of Mo noticeably changes under the presence of Pt. Thus, the TPR profile of Mo/Si sample shows a broad reduction profile with a hydrogen consumption H 2 /Mo equal to 1.01, due to the reduction of Mo(VI) into Catálisis para un mundo más sosten ible O/P ## Role of Mo in catalysts based on noble metals in hydrodeoxygenation reactions - García, E. Rodríguez- - CSIC), Facultad de Ciencias, energy as a renewable alternative to fossil fuels is nowadays attracting more and more to be a potential energy substitute for fossil fuels since it is a renewable resource that could contribute to sustainable development and glo bal environmental . The problem is its high oxygen content, properties for combustion. To remove oxygen, catalytic hydrodeoxygenation (HDO) ometallic Mo/Si, Pt/Si as well as bimetallic PtMo/Si catalysts were prepared (DBF) as a model molecule in containing 2 wt% of metal and a Pt/Mo molar . Moreover, Pt and Mo , were also synthesized in order to evaluate the were characterized by different experimental to understand its structure, catalytic activity. For the activity ) were used, diluted with SiC to 3 cm 3 . Catalytic flow rate was 30 mL·min -1 and the of the monometallic samples do not differ considerably compared to the , characteristic of materials with meso and at relative pressures higher than 0.8, indicating the presence of pores of larger diameter. The increase in volume is due to the fact that showed the presence of was evidenced in the case the presence of tiny diffraction peaks due to the presence of Pt 0 was only dispersed and instead Pt is more TPR and TPD data are considered, the behavior of Mo noticeably changes under the presence of Pt. Thus, the TPR profile of Mo/Si sample shows a broad due to the reduction of Mo(VI) into Oviedo, June 26 – 28, 2017 Mo(IV). Instead, in the bimeta llic sample the hydrogen consumption is very low. In line with this, a similar behavior is observed from NH 3 - TPD data (Table 1). Mo/Si sample desorbs a large amount of ammonia mainly in the range of weak strength acidity. Neverth of monometallic Pt and bimetallic PtMo samples. These data point to a kind of interaction between Pt and Mo that modulates the reducibility and acidity of the bimetallic catalysts. Monometallic catalysts were evaluated in the HDO reaction of d pressure (Figure 1) . These catalysts fail to achieve the conversion values obtained with the bimetallic catalysts, the best conversion being that of the monometall value of 55%. Monometallic m olybdenum oxide catalyst did not showed acti While, bimetallic catalyst showed a HDO conversion value near 80% at 15 bar. be extracted from this graph: a lthough molybdenum oxide alone did not presented catalytic activity, it plays an important role when added to a nobl capability improved if compared to the monometallic ones. Therefore it can be thought that Mo promotes the hydrogenolysis reaction. Pt/Si PtMo/Si 0 20 40 60 80 100 Conversion (%) HDO Total Figure 1. C onversion values after 6 hours on stream for mono and bimetallic catalysts.. Reaction conditions: T = 275 ºC, P: 15 bar, LHSV = 3.6 h −1 , GHSV = 7200 Ncc/g cat h, H H 2 /DBF=69.1. 4. Conclusions Experimental results showed that the active phase had much influence on the activity and selectivity to the different reaction products, although, in all c bimetallic catalyst . Molybdenum species improved the selectivity to capacity to break the CO bond. However, References 1. Demirbaş, A., Biomass resource facilities and biomass conversion processing for fuels and chemicals. Conversion and Management 2001, 42 2. InfantesMolina, A.; Moretti, E.; Segovia, E.; Lenarda, A.; Rodríguez catalysts supported on silica and zirconium phosphate heterostructures for O Today 2016, 277, 143-151. Catalysis for a more sustainable world llic sample the hydrogen consumption is very low. In line with this, a similar TPD data (Table 1). Mo/Si sample desorbs a large amount of ammonia the range of weak strength acidity. Neverth eless, the acidity is much m ore and bimetallic PtMo samples. These data point to a kind of interaction between Pt and that modulates the reducibility and acidity of the bimetallic catalysts. evaluated in the HDO reaction of d ibenzofuran, at 275 °C and . These catalysts fail to achieve the conversion values obtained with the bimetallic catalysts, the best conversion being that of the monometall ic Pt catalyst, which showed a HDO conversion olybdenum oxide catalyst did not showed acti vity under the same conditions. a HDO conversion value near 80% at 15 bar. Important conclusions can lthough molybdenum oxide alone did not presented catalytic activity, it plays an important role when added to a nobl e metal catalyst. Thus, in bimetallic catalyst capability improved if compared to the monometallic ones. Therefore it can be thought that Mo promotes PtMo/Si Total Sample S BET (m 2 g −1 ) Acidity (µmol NH Weak SiO 2 217 - Mo/SiO 2 161 434 Pt/SiO 2 188 30 PtMo/SiO 2 192 61 onversion values after 6 hours on stream for mono and bimetallic catalysts.. Reaction conditions: T = 275 ºC, P: 15 bar, H 2 contact time = 6 s, Table 1. T extural and acidic properties of the different samples prepared. that the active phase had much influence on the activity and selectivity to the different reaction products, although, in all c ases . Molybdenum played a very important role in t . Molybdenum species improved the selectivity to Ofree products and related to its O bond. However, molybdenum activity was nil in absence of noble metal. Demirbaş, A., Biomass resource facilities and biomass conversion processing for fuels and chemicals. (11), 1357-1378. Molina, A.; Moretti, E.; Segovia, E.; Lenarda, A.; Rodríguez - Castellón, E., Pd catalysts supported on silica and zirconium phosphate heterostructures for O - removal of dibenzofurane. Catalysis for a more sustainable world O/P ## llic sample the hydrogen consumption is very low. In line with this, a similar TPD data (Table 1). Mo/Si sample desorbs a large amount of ammonia ore moderate in the case and bimetallic PtMo samples. These data point to a kind of interaction between Pt and ibenzofuran, at 275 °C and 15 bar of . These catalysts fail to achieve the conversion values obtained with the bimetallic showed a HDO conversion vity under the same conditions. Important conclusions can lthough molybdenum oxide alone did not presented catalytic activity, it Thus, in bimetallic catalyst the HDO capability improved if compared to the monometallic ones. Therefore it can be thought that Mo promotes Acidity (µmol NH 3 g − 1 ) Medium Strong Total - - - 78 0 512 33 4 67 35 19 115 extural and acidic properties of the different samples prepared. that the active phase had much influence on the activity and selectivity to the . Molybdenum played a very important role in t he case of free products and related to its molybdenum activity was nil in absence of noble metal. Demirbaş, A., Biomass resource facilities and biomass conversion processing for fuels and chemicals. Energy Castellón, E., Pd -Nb binfunctional removal of dibenzofurane. Catalysis