Catalytic functionalities of nano Ru catalysts supported on TiO2-ZrO2 mixed oxide for vapor phase hydrogenolysis of glycerol to propanediols

Vapor phase hydrogenolysis of glycerol was studied over Ru catalysts supported on TiO2-ZrO2 binary oxide. Ru catalysts with various ruthenium loadings from 1.0 to 6.0 wt% were prepared by deposition-precipitation method on the TiO2-ZrO2 mixed oxide support. These catalysts were characterized by X-ray diffraction, H-2 temperature-programmed reduction, NH3 temperature-programmed desorption, transmission electron microscopy, BET surface area, XPS and CO chemisorption measurements. The catalysts exhibited superior performance for the vapor phase hydrogenolysis of glycerol at moderate temperature and atmospheric pressure. The mixed oxide support plays a significant role in improving the catalytic activity for the production of propanediols. The glycerol conversion and the selectivity of various products depend on the catalyst preparation method and also on the Ru content. The influence of acidity of the catalyst and its correlation to the catalytic performance (selectivity and conversion) has been studied. The weak and strong acidic sites of the catalysts measured by NH3-TPD play a key role in selective formation of 1,2-propanediol and 1,3-propanediol. XRD, TEM, XPS and CO chemisorption studies revealed that ruthenium was well dispersed on TiO2-ZrO2 which further contributed to the superior catalytic activity for glycerol hydrogenolysis

Activity and Selectivity of Platinum–Copper Bimetallic Catalysts Supported on Mordenite for Glycerol Hydrogenolysis to 1,3-Propanediol

Biomass derived glycerol is considered an ideal feedstock with a prospective to be converted into a number of valuable compounds. Catalytic glycerol hydrogenolysis to produce 1,3-propanediol is one of the pioneering biosustainable pathways. Bimetallic Pt–Cu catalysts supported on H-mordenite were synthesized with various copper loadings and applied in the selective glycerol hyrogenolysis to 1,3-propanediol in a continuous fixed bed reactor performed in vapor phase under atmospheric pressure. Several techniques such as XRD, ICP-AES, NH₃-TPD, Pyr FTIR, BET, TPR, HR-TEM, XPS, and solid state NMR were employed to characterize the physical and chemical properties of Pt–Cu/Mor catalysts. A detailed reaction parametric study has been carried out. The results designated that well dispersed Pt–Cu catalysts with small particle size, supported on a Brønsted acidic H-mordenite with a multiple pore system and strong bimetallic phase-support interaction, promote the selectivity to 1,3-propanediol. Over the Pt–Cu/Mor catalyst of optimum composition (2% Pt and 5% Cu by weight) and under the optimum reaction conditions (210 °C, H₂ flow rate of 80 mL min^–1, and gly concentration of 10 wt %), the glycerol conversion and 1,3-PD selectivity reached 90% and 58.5%, respectively. Structural characterizations and reusability of the Pt-5Cu/Mor catalyst were also performed. With evident advantages of selective C–O hydrogenolysis with low C–C cleavages, the bimetallic Pt–Cu/Mor catalysts hold great potential as high-performance catalysts for glycerol conversion to 1,3-propanediol

Lanthanum phosphate:an efficient catalyst for acrylic acid production through lactic acid dehydration

Abstract In this work, biomass-based platform molecule lactic acid conversion to acrylic acid has been studied. A series of lanthanum phosphate (LaP) catalysts prepared by varying the lanthanum to phosphorus (La/P) mole ratio (i.e., 0.2, 0.35, 0.5, 1.0, and 2.0) and also prepared at different calcination temperatures (i.e., 400, 500, 600, and 800 °C) were investigated. The catalysts were characterized by using different techniques and tested in the dehydration of lactic acid (LA) to acrylic acid (AA) production. All the synthesized catalysts were characterized to analyze the physicochemical properties such as degree of crystallinity, total surface acidity, specific surface area, and morphology. The La/P mole ratio was found to be significant in designing the optimized catalytic system. The NH₃-TPD results imply that all the catalysts exhibited varied amount of total acidity with phosphate loadings, which are mostly weak acid sites. The weak acid sites which are mainly Lewis acidity type played an important role in producing AA selectively and efficiently from the LA conversion. The most optimized reaction conditions were determined to obtain the highest LA conversion, selectivity, and AA yield. The catalyst with an La/P mole ratio of 0.35 and calcined at 500 °C exhibited the best performance with complete LA conversion, AA selectivity of ~ 74%, and a maximum yield of AA of ~ 74%. Furthermore, the LaP(0.35)[500] catalyst was successfully tested at three different time on streams and found to be stable

Synergistic effects of graphene oxide grafted chitosan & decorated MnO2 nanorods composite materials application in efficient removal of toxic industrial dyes

Abstract In this study, we designed a heterogeneous graphene oxide (GO) grafted on chitosan decorated with MnO2 nanorods (α-MnO2NRs/GO-Chit) composite materials and its ability to remove the cationic and anionic toxic dyes from wastewaters were analysed. The synthesised materials presented an effective stabilization of active MnO2 nanorods (NRs) on the GO-Chit surface. The synthesised materials were detailed characterised by several spectroscopic and microscopic techniques such as, FT-IR, P-XRD, SEM, TEM, Raman, TGA, XPS, BET, CO2-TPD and UV–Visible analysis. In addition, α-MnO2NRs/GO-Chit material is successfully applied in removal of industrial ionic dyes such as amido black 10B (AB) and methylene blue (MB), respectively. The dye adsorption experiments confirmed that the GO-Chit/α-MnO2 NRs material exhibited remarkably high adsorption capacity in efficient removal of cationic dye methylene blue (MB) and anionic dye amido black 10B (AB). The maximum MB dye removal (97%) process completed in 24 min at C0 = 30 mg·L-1, but in the case of AB the maximum dye removal (80%) process was reached in 700 min. Over GO-Chit/α-MnO2 NRs hybrid material, a maximum theoretical monolayer adsorption (qmax values is 328.9 mg g-1) of MB was calculated from the Langmuir isotherm equation. In case MB, a faster adsorption and 2.18 times maximum adsorption capacity was achieved than that of AB10 dye. The enhanced adsorption over α-MnO2NRs/GO-Chit is due to the increased surface functionalities (i.e., oxygen-containing groups), high basicity and strong electrostatic forces between MnO2 nanorods and GO-Chit. Furthermore, α-MnO2NRs/GO-Chit hybrid material displayed good stability after 10 successive adsorption tests

Selective hydrogenolysis of biodiesel waste bioglycerol over titanium phosphate (TiP) catalysts:the effect of Pt & WO₃ loadings

Abstract Glycerol is an important by-product (biowaste) from biodiesel production. Transformation of glycerol into value-added compounds is critical in improving the overall efficiency of the biodiesel production. In this work, a sustainable and cleaner production of 1,3-propanediol (1,3-PDO) by vapor phase hydrogenolysis of glycerol was performed over titanium phosphate (TiP) supported catalysts by varying the Pt and WO₃ loadings (5–20 wt.%). The WO₃ promoted Pt modified TiP catalysts were prepared by a simple wet impregnation method and characterized by various analytical techniques in determining the key properties. Furthermore, the catalyst activity and stability were studied under different reaction conditions. The synergistic effects of Pt and WO₃ loadings on the final performance of the catalyst has been significant in improving the hydrogen transfer rate. Both Pt and WO₃ promotional effects is envisaged the enhanced catalytic properties in conjunction with TiP support acidity. WO₃ incorporation increased Brønsted acidity and formed strong interactions with Pt over TiP support. Both Lewis and Brønsted acid sites presented but BAS played a key role in enhancing the 1,3-PDO selectivity in a bifunctional dehydration-hydrogenation reaction mechanism of glycerol. The effect of reaction temperature, contact times and the weight hour space velocity were evaluated. Overall, under optimized reaction conditions, 2 wt.% Pt-10 wt.% WO₃/TiP catalyst displayed superior activity with a maximum glycerol conversion of ~ 85% and ~ 51% of 1,3-PDO selectivity achieved at time on stream of 4 h

Platinum Supported on H‑Mordenite: A Highly Efficient Catalyst for Selective Hydrogenolysis of Glycerol to 1,3-Propanediol

The selective production of 1,3-propanediol from glycerol under mild reaction conditions is of high interest. The current work describes the use of a highly selective catalyst consisting of platinum supported on mordenite zeolite employed for the first time for vapor phase hydrogenolysis of glycerol to 1,3-propanediol under atmospheric pressure. The catalysts with varying Pt content (0.5–3 wt %) were prepared and thoroughly characterized by X-ray diffraction, temperature-programmed desorption of ammonia, FT-IR of adsorbed pyridine, CO chemisorptions, transmission electron microscopy, X-ray photoelectron spectroscopy, and BET surface area. The influence of reaction parameters has been studied to unveil the optimized reaction conditions. A high 1,3-propanediol selectivity (48.6%) was obtained over a 2 wt % Pt/H–mordenite catalyst at 94.9% glycerol conversion. According to the results obtained, the selectivity to 1,3-propanediol is better influenced by Pt dispersion and Brønsted acidity of the support. A plausible reaction mechanism has been presented. The spent catalyst exhibited consistent activity and selectivity toward the desired product during the glycerol hydrogenolysis reaction