Effects of Heterogeneous Catalyst Preparation Methods on
Steven Zhou and Jason Yang
Journal of X-Catalysis Group, 2017, 1(12), pp 22-30
The molecules extracted from bio-based resources already contain functional groups, so that the synthesis of chemicals generally requires a lower number of steps than from alkanes, while heterogeneous catalysts are still required to convert these molecules to valuable chemicals and/or biofuels. Catalyst preparation method plays an important role in its performance for biomass conversion. In the present work, effects of heterogeneous catalyst preparation methods on biomass conversion are compared and discussed. For certain biomass molecules, specific catalyst preparation method is proposed.
Biomass is first converted by gasification to synthesis gas, or by pyrolysis to a mixture of small molecules. Synthesis gas may then be converted to hydrocarbons which are subsequently converted to intermediates, using the classical synthesis routes developed for petroleum feedstock. Similarly, small molecules obtained by biomass pyrolysis may, after separation, be converted to valuable chemicals via the existing flow sheets of chemical synthesis. [1, 2, 3, 4, 5, 6, 7] This is not a cost-effective and environmentally sustainable route for chemical production, as highly functionalized molecules from biomass are first degraded to C1 molecules or hydrocarbons which are then subjected to the traditional chemical synthesis steps in order to be functionalized again. [8, 9, 10, 11, 12, 13]
A biorefinery is a facility that integrates biomass conversion processes to produce fuels and chemicals. According to this scheme, part of the biomass is converted to fuels via pyrolysis and gasification, and the other part is converted by fermentation or chemocatalytic routes to well-identified platform molecules, that can be employed as building blocks in chemical synthesis. The fermentation processes are continuously improved with new, genetically modified bacteria or yeasts. [14, 15, 16, 17]
Vegetables oils, and most of the carbohydrates used to produce chemicals, are issued from grains harvested primarily for food and feed, and their productivity is rather low, for example between 3 and 8 tons of dry matter per hectare of cultivated land. [18, 19, 20, 21, 22, 23] In contrast, the non-grain portion of biomass - that is, the agricultural wastes (cobs, stalk, stovers) and vegetative biomass (trees, leaves, etc.) - are barely used to produce chemicals, in spite of their much greater availability. Lignocellulosic materials are built on the intimate mixture of cellulose, hemicellulose and lignin that is difficult to separate and to process.Cellulose polymers are glucoside units connected via 1,4-glycosidic linkages instead of -linkages in the case of starch; they are therefore more stable and difficult to hydrolyze by chemical or enzymatic means. Hemicelluloses are more easily hydrolyzed than celluloses, and yield valuable pentoses such as xylose and arabinose. [24, 4, 25, 26, 27] They are, potentially, a very important and as-yet largely untapped renewable source of chemicals. Lignins have a very complex polymeric structure based on interconnected aromatic derivatives, and they are very recalcitrant materials to process. Nonetheless, chemicals such as vanillin can be obtained via the catalytic oxidation of lignosulfonate.
The activity of solid catalysts is usually proportional to the active surface area per unit volume of catalyst, provided that transport limitations are not present. [28, 7, 29, 30] A high activity per unit volume calls for small particles.  As most active species sinter rapidly at the temperatures at which the thermal pretreatment and the catalytic reaction proceed, small particles of the active species alone generally do not provide thermostable, highly active catalysts. To arrive at solid catalysts of the desired shape, mechanical strength, porous structure, activity, and thermal stability, two different materials, the support and the active material - provide the different functions that the catalyst must fulfill.  The support, which is usually highly thermostable, furnishes the shape, mechanical strength and porous structure, while the catalytic activity and selectivity are due to the active component(s). As indicated in Figure 1, the sintering of small particles alone leads to a low active surface area, whereas application of the active component on a support can stabilize the active surface area.
The most favorable size for supported active particles has only seldom been established, the reason being that it is difficult to vary systematically the size of the active particles deposited onto a support while maintaining a narrow particle size distribution.  It is, consequently, desirable to apply the active component(s) uniformly and densely distributed over the surface of the support as particles the size of which can be controlled. This is one of the main goals when preparing supported catalysts by deposition-precipitation.
The methods most frequently used to achieve the deposition of the active component precursor are impregnation, ion exchange, anchoring, grafting, spreading and wetting, heterogenization of complexes, deposition-precipitation (homogeneous and redox), and adapted methods in the case of supported bimetallic catalysts. [34, 35] In some cases, the active component (not its precursor form) can be deposited directly onto the support. In the following sections only the case of a single active component will be discussed. When several active components are required, they can be deposited consecutively or simultaneously. Although the problem becomes more complicated because of possible interferences, it can be treated with the same basic concepts presented here. [36, 37, 38]
Ion exchange is an operation which consists of replacing an ion in an electrostatic interaction with the surface of a support by another ion species. The support containing ion A is plunged into an excess volume (much larger than the pore volume) of a solution containing ion B that is to be introduced. Ion B gradually penetrates into the pore space of the support and takes the place of ion A, which passes into the solution, until an equilibrium is established corresponding to a given distribution of the two ions between the solid and the solution. The solid is then washed, and finally separated by filtration or centrifugation. [39, 40]
When the pore space of the support has first been filled up with pure solvent of the impregnation solution prior to being placed in contact with the latter, the characteristics defined above are valid only for the first step of saturation by the solvent. The second step is generally an immersion that consists of plunging the solvent-saturated support into the impregnation solution. This step is no longer exothermic and does not cause the development of high pressure inside the pore space. The driving force of the progressive migration of the salt into the heart of the grains is the concentration gradient between the extragranular solution and the moving front of the soluble precursor in the intergranular solution.  The migration time is obviously much longer than for capillary impregnation.
Precipitation of an active precursor onto a support suspended in a solution of the precursor can provide high loadings, as the compound(s) dissolved in a liquid volume that is large compared to the support pore-volume, are concentrated onto the support. [42, 43] Besides coprecipitation of the precursors of the support and the active material and subsequent selective removal of some components, precipitation in the presence of a suspended support is also often carried out to achieve high loadings of the support. The apparatus and procedures do not differ significantly, but the precipitation usually proceeds where the precipitating liquid enters the suspension, and the precipitant necessarily does not enter the liquid present in the porous conglomerates of the support. When nucleation and growth of the precipitate of the precursor are rapid, large crystallites of the precursor result. With a rapid nucleation and slow growth (which is usually encountered with poorly soluble compounds), clusters of small particles of the active precursor outside the pore system of the support are often obtained. [44, 45] At high concentrations, at a point where the precipitant enters the suspension, the small particles rapidly and irreversibly flocculate, which leads to the clustering of small particles. Catalysts prepared in this way are liable to rapid deactivation during pretreatment or use at elevated temperatures, as the small elementary particles of the precursor are intimately connected and therefore sinter readily.
The chemical interaction of metal ions precipitating from a homogeneous solution with silica at higher temperatures has been widely confirmed. With finely divided silica, reaction to synthetic clay minerals has been established. Consequently, the reaction is not confined to the surface of silica, but also involves the bulk of small silica particles. Reaction to another solid phase was already concluded from the maximum through which the pH curve often passes during the deposition-precipitation of nickel at a temperature of about 350 K, or higher. The complete reaction of the silica particles is also evident from electronmicrographs, which show a complete disappearance of the silica particles initially present. When the amount of bivalent metal ions is insufficient to convert the silica completely, the growth of platelets of clay minerals from the silica particles can easily be seen. [15, 46]
In the present work, effects of heterogeneous catalyst preparation methods on biomass conversion are compared and discussed. It is concluded that for certain biomass molecules, specific catalyst preparation method is proposed.
This work was supported X-Catalysis Group (x-catalysis.com).
 Geus, Eduard R., van Bekkum, Herman, Bakker, Wridzer J.W., and Moulijn, Jacob A., “High-temperature Stainless Steel Supported Zeolite (MFI) Membranes: Preparation, Module Construction, and Permeation Experiments,” Microporous Materials, volume 1, no. 2, pp. 131 – 147, 1993
 Xiao, Yang, Xiao, Guomin, and Varma, Arvind, “A Universal Procedure for Crude Glycerol Purification from Different Feedstocks in Biodiesel Production Experimental and Simulation Study,” Industrial Engineering Chemistry Research, volume 52, no. 39, pp. 14291–14296, 2013
 Hong, Seok-Min, Lim, Geunsik, Kim, Sung Hyun, Kim, Jong Hak, Lee, Ki Bong, and Ham, Hyung Chul, “Preparation of Porous Carbons Based on Polyvinylidene Fluoride for CO2 Adsorption: a Combined Experimental and Computational Study,” Microporous and Mesoporous Materials, volume 219, pp. 59 – 65, 2016
 Golinska-Mazwa, Hanna, Decyk, Piotr, and Ziolek, Maria, “Sb, V, Nb Containing Catalysts in Low Temperature Oxidation of Methanol - the Effect of Preparation Method on Activity and Selectivity,” Journal of Catalysis, volume 284, no. 1, pp. 109 – 123, 2011
 Saucedo, Jose A., Xiao, Yang, and Varma, Arvind, “Platinum-Bismuth Bimetallic Catalysts: Synthesis, Characterization and Applications,” The Summer Undergraduate Research Fellowship SURF Symposium, 2015
 Maksimov, A. L., Nekhaev, A. I., Ramazanov, D. N., Arinicheva, Yu. A., Dzyubenko, A. A., and Khadzhiev, S. N., “Preparation of High-Octane Oxygenate Fuel Components from Plant-Derived Polyols,” Petroleum Chemistry, volume 51, no. 1, pp. 61–69, 2011
 Kampers, F. W. H., Engelen, C. W. R., van Hooff, J. H. C., and Koningsberger, D. C., “Influence of Preparation Method on the Metal Cluster Size of Pt/ZSM-5 Catalysts as Studied with Extended X-ray Absorption Fine Structure Spectroscopy,” J Phys Chem, volume 94, pp. 8574–8578, 1990
 Gao, Danni, Xiao, Yang, and Varma, Arvind, “Guaiacol Hydrodeoxygenation over Platinum Catalyst: Reaction Pathways and Kinetics,” Industrial Engineering Chemistry Research, volume 54, no. 43, pp. 10638–10644, 2015
 Qian, Guang, Luo, Xu, and Wang, Jianmin, “High Bismuth Content Bi-MCM-41: Synthesis, Characterization and Investigation on the Distribution of Bismuth Atoms,” Microporous and Mesoporous Materials, volume 112, no. 1-3, pp. 632 – 636, 2008
 Qian, Guang, Ji, Dong, Lu, Gaomeng, Zhao, Rui, Qi, Yanxing, and Suo, Jishuan, “Bismuth-containing MCM-41: Synthesis, Characterization, and Catalytic Behavior in Liquid-Phase Oxidation of Cyclohexane,” Journal of Catalysis, volume 232, no. 2, pp. 378 – 385, 2005
 Zhang, Hongli, Liu, Seng, Hu, Bin, Zhang, Fang, Sun, Peiyong, Zhang, Shenghong, and Yao, Zhilong, “Kinetics of Biodiesel Preparation by Transesterification of Soybean Oil Catalyzed with K/MgO-Al2O3,” China Oils, volume 41, no. 11, pp. 57–61, 2016
 Ameur, Nawel, Berrichi, Amina, Bedrane, Sumeya, and Bachir, Redouane, “Preparation and Characterization of Au/Al2O3 and Au-Fe/Al2O3 Materials, Active and Selective Catalysts in Oxidation of Cyclohexene,” Advanced Materials Research, volume 856, pp. 48–52, 2014
 Xiao, Yang, Greeley, Jeffrey, Varma, Arvind, Zhao, Zhi-Jian, and Xiao, Guomin, “An Experimental and Theoretical Study of Glycerol Oxidation to 1,3-Dihydroxyacetone over Bimetallic Pt-Bi Catalysts,” AIChE Journal, volume 63, no. 2, pp. 705–715, 2017
 Beznis, Nadzeya V., Weckhuysen, Bert M., and Bitter, Johannes H., “Partial Oxidation of Methane over Co-ZSM-5: Tuning the Oxygenate Selectivity by Altering the Preparation Route,” Catalysis Letters, volume 136, no. 1, pp. 52–56, 2010
 Xiao, Yang, Gao, Lijing, Xiao, Guomin, and Lv, Jianhua, “Kinetics of the Transesterification Reaction Catalyzed by Solid Base in a Fixed-Bed Reactor,” Energy Fuels, volume 24, no. 11, pp. 5829–5833, 2010
 Eswaramoorthy, M., Niwa, S., Toba, M., Shimada, H., Raj, A., and Mizukami, F., “The Conversion of Methane with Silica-Supported Platinum Catalysts: the Effect of Catalyst Preparation Method and Platinum Particle Size,” Catalysis Letters, volume 71, no. 1, pp. 55–61, 2001
 Du, Yongling and Wang, Chunming, “Preparation Ru, Bi Monolayer Modified Pt Nanoparticles as the Anode Catalyst for Methanol Oxidation,” Materials Chemistry and Physics, volume 113, no. 2, pp. 927 – 932, 2009
 Choudhary, V.R., Rane, V.H., and Gadre, R.V., “Influence of Precursors Used in Preparation of MgO on Its Surface Properties and Catalytic Activity in Oxidative Coupling of Methane,” Journal of Catalysis, volume 145, no. 2, pp. 300 – 311, 1994
 Xiao, Yang, Gao, Lijing, Xiao, Guomin, Fu, Baosong, and Niu, Lei, “Experimental and Modeling Study of Continuous Catalytic Transesterification to Biodiesel in a Bench-Scale Fixed-Bed Reactor,” Industrial Engineering Chemistry Research, volume 51, no. 37, pp. 11860–11865, 2012
 Hermans, Sophie, Deffernez, Aurore, and Devillers, Michel, “Preparation of Au-Pd/C Catalysts by Adsorption of Metallic Species in Aqueous Phase for Selective Oxidation,” Catalysis Today, volume 157, no. 1-4, pp. 77 – 82, 2010
 Han, Zhansheng, Pan, Wei, Pan, Weixiong, Li, JinIu, Zhu, Qiming, Tin, Kamchung, and Wong, Ningbew, “Preparation and Effect of Mo-V-Cr-Bi-Si Oxide Catalysts on Controlled Oxidation of Methane to Methanol and Formaldehyde,” Korean Journal of Chemical Engineering, volume 15, no. 5, pp. 496–499, 1998
 Isahak, W. N R W, Ismail, M., Yarmo, M. A., Jahim, J. M., and Salimon, J., “Purification of Crude Glycerol from Transesterification Rbd Palm Oil over Homogeneous and Heterogeneous Catalysts for the Biolubricant Preparation,” Journal of Applied Sciences, volume 10, no. 21, pp. 2590–2595, 2010
 Xiao, Yang and Varma, Arvind, “Experimental and simulation study of crude glycerol purification from different feed stocks in biodiesel production,” Abstract of Papers of the American Chemical Society, volume 246, 2013
 Kirichenko, O.A., Redina, E.A., Davshan, N.A., Mishin, I.V., Kapustin, G.I., Brueva, T.R., Kustov, L.M., Li, Wei, and Kim, Chang Hwan, “Preparation of Alumina-Supported Gold-Ruthenium Bimetallic Catalysts by Redox Reactions and Their Activity in Preferential CO Oxidation,” Applied Catalysis B Environmental, volume 134-135, pp. 123 – 129, 2013
 Menchavez, Russel N., Morra, Matthew J., and He, B. Brian, “Co-Production of Ethanol and 1,2-Propanediol via Glycerol Hydrogenolysis Using Ni/Ce-Mg Catalysts: Effects of Catalyst Preparation and Reaction Conditions,” Catalysts, volume 7, no. 290, p. doi:10.3390/catal7100290, 2017
 Papageorgiou, Panayiotis, Price, Douglas M., Gavriilidis, Asterios, and Varma, Arvind, “Preparation of Pt/γ-Al2O3 Pellets with Internal Step-Distribution of Catalyst: Experiments and Theory,” Journal of Catalysis, volume 158, no. 2, pp. 439 – 451, 1996
 Ohman, L.O., Ganemi, B., Bjornbom, E., Rahkamaa, K., Keiski, R.L., and Paul, J., “Catalyst Preparation through Ion-Exchange of Zeolite Cu-, Ni-, Pd-, CuNi- and CuPd-ZSM-5,” Materials Chemistry and Physics, volume 73, no. 2-3, pp. 263 – 267, 2002
 Li, Haoyang, Pan, Xiaomei, Xiao, Yang, Xiao, Guomin, and Huang, Jinjin, “Simulation of Biodiesel Industrial Production via Solid Base Catalyst in a Fixed-Bed Reactor,” Journal of Southeast University English version, volume 30, no. 3, pp. 380–386, 2014
 Reddy, Jakkidi Krishna, Lalitha, Kannekanti, Durga Kumari, Valluri, and Subrahmanyam, Machiraju, “Photocatalytic Study of Bi-ZSM-5 and Bi2O3/HZSM-5 for the Treatment of Phenolic Wastes,” Catalysis Letters, volume 121, no. 1, pp. 131–136, 2008
 Popov, T.S., Klissurski, D.G., Ivanov, K.I., and Pesheva, J., “Effect of Ultrasonic Treatment on the Physicochemical Properties of Cr-Mo-O Catalysts for Methanol Oxidation,” volume 31, pp. 191 – 197, 1987
 Ryoo, Ryong, Ko, Chang Hyun, Kim, Ji Man, and Howe, Russell, “Preparation of Nanosize Pt Clusters Using Ion Exchange of Pt(NH3)2+inside Mesoporous Channel of MCM-41,” Catalysis Letters, volume 37, no. 1, pp. 29–33, 1996
 Wang, Yun, Hu, Sheng-yang, Guan, Yan-ping, Wen, Li-bai, and Han, He-you, “Preparation of Mesoporous Nanosized KF/CaO–MgO Catalyst and Its Application for Biodiesel Production by Transesterification,” Catalysis Letters, volume 131, no. 3, pp. 574–578, 2009
 Tshabalala, Themba E., Coville, Neil J., Anderson, James A., and Scurrell, Michael S., “Dehydroaromatization of Methane over Sn-Pt Modified Mo/H-ZSM-5 Zeolite Catalysts: Effect of Preparation Method,” Applied Catalysis A General, volume 503, pp. 218 – 226, 2015
 Xin, Mei, Hwang, In Chul, Kim, Do Heui, Cho, Se In, and Woo, Seong Ihl, “The Effect of the Preparation Conditions of Pt/ZSM-5 Upon Its Activity and Selectivity for the Reduction of Nitric Oxide,” Applied Catalysis B Environmental, volume 21, no. 3, pp. 183 – 190, 1999
 Wang, Weiyan, Yang, Sijun, Qiao, Zhiqiang, Liu, Pengli, Wu, Kui, and Yang, Yunquan, “Preparation of Ni-W-P-B Amorphous Catalyst for the Hydrodeoxygenation of p-Cresol,” Catalysis Communications, volume 60, pp. 50 – 54, 2015
Effects of Heterogeneous Catalyst Preparation Methods on
Steven Zhou and Jason Yang
Journal of X-Catalysis Group, 2017, 1 (12), pp 22-30
Catalog: Catalyst Preparation
X-Catalysis Group Thank you for visiting our website. This is X-Catalysis Group, a non-profit professional organization dedicated to assisting catalysis students and young professionals in fully realizing their potential in academic, professional, and entrepreneurial pursuits in chemistry, chemical engineering, and allied fields. We invite you to browse our website, engage with us on social media, talk to our members, attend our annual conference and discover the X-Catalysis Group spirit for yourself.
See discussions, stats, and author profiles for this publication at x-catalysis.com