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The oxidative reaction pathway of organic nitrogen in the catalytic oxidative denitrogenation could be successfully elucidated.

The industrial use of biomass, e.g., for the production of platform chemicals such as levulinic acid, became increasingly important in recent years. However, the efficiency of these processes was reduced by the formation of insoluble solid waste products called humins. Herein, the formation of humins from various carbohydrates was investigated under different process conditions, in order to obtain information about the structure and the formation mechanism. During this process, new potential structural fragments of humins were identified. Subsequently, the produced humins were oxidatively converted to low-molecular-weight carboxylic acids with the use of polyoxometalate catalysts. The experiments showed that the use of sugars in acetic acid and ethanol only lead to the formation of a small amount of humins, which were also structurally most suitable for conversion to carboxylic acids. The main products of the oxidative valorisation of these humins were acetic acid, formic acid, and CO2, respectively, and our results indicate that certain functional groups were converted preferentially. These findings will help to improve processes for the valorisation of biomass by enabling an overall more efficient use of thermo-sensitive feedstock such as carbohydrates.

Simultaneous generation and activation of Raney-type periodic open cellular structures (POCS) is a highly promising approach for generating novel structured methanol synthesis catalysts. In detail, we produced stable and highly active POCS from a Cu50Al50 alloy by additive manufacturing via Powder Bed Fusion by Electron Beam (PBF-EB) and activated them via selective leaching of aluminum in a sodium hydroxide/sodium zincate solution. The Raney-type Cu structures possessed catalytic methanol productivities of up to 2.2 gMeOHgnp-Cu h−1 (PBF-EB sticks) and 1.9 gMeOHgnp-Cu h−1 (PBF-EB POCS), respectively. Moreover, it was found that besides the nanoporous layer thickness, an optimum Zn/Cu ratio of 0.3–0.4 can also by adjusted by the leaching conditions.

Alcoholic solvents, especially methanol, show an activating affect for heteropolyacids in homogenously catalysed glucose transformation reactions. In detail, they manipulate the polyoxometalate‐based catalyst in a way that thermodynamically favoured total oxidation to CO2 can be completely supressed. This allows a nearly 100 % carbon efficiency in the transformation reaction of glucose to methyl formate in methanolic solution at mild reaction conditions of 90 °C and 20 bar oxygen pressure. By using powerful spectroscopic tools like 51V‐NMR and continuous wave EPR we could unambiguously prove that the vanadate‐methanol‐complex[VO(OMe)3]n is responsible for the selectivity shift in methanolic solution compared to the aqueous reference system.

Adjusting the RedOx activity of polyoxometalate catalysts is a key challenge for the catalysis of selective oxidation reactions. For this purpose, the possibility of influencing the RedOx potential by the introduction of an additional RedOx-active element was investigated. Thereby, Keggin-type polyoxometalates (POMs) with up to three different elements in the metal framework were created. An advanced and reproducible synthetic procedure to incorporate Mn

The recently developed polyoxometalate (POM)–ionosolv concept offers an interesting strategy to generate two valuable product streams from lignocellulosic biomass, a solid cellulose-rich pulp and short-chain carboxylic acids like formic acid and acetic acid in a simple and cost-efficient manner. This study aimed to find optimum parameters for the two steps of the transformation by performing a sensitivity analysis on the initial ionosolv fractionation step as well as kinetic investigations of the following POM-catalyzed oxidation step. The results were transferred to the POM–ionosolv concept to find the overall process optimum. Beech wood was used as an industrially relevant substrate for ionosolv fractionation with the low-cost ionic liquid triethylammonium sulfate, [TEA][HSO4], and the HPA-5 [H8PV5Mo7O40] POM catalyst for the oxidation of the dissolved components in an oxygen atmosphere. As the most seminal finding, we defined optimum conditions of 125 °C, 1200 rpm, 30 bar oxygen, and 24 h reaction time in ionic liquid containing 70% water, achieving 72% xylose extraction from beech wood, which resulted in a 39% formic acid yield. We suggest that the fractionation and catalytic conversion are carried out at different water contents for maximum conversion efficiency for each step.

ACS omega 5(30), 19082-19091 (2020). doi:10.1021/acsomega.0c02430, Published by ACS Publications, Washington, DC

In this contribution, we successfully apply our recently developed extractive catalytic oxidative desulfurization technology (ECODS) for the removal of different nitrogen-containing compounds (ECOD...

In this contribution, we present for the first time a continuous production of formic acid under industrially relevant conditions using real biomass as a feedstock. A scale up to 2 L of reaction vo...

The triphasic aerobic extractive desulfurization of benzothiophene (BT) using an aqueous H8PV5Mo7O40 solution as catalyst and O2 as oxidant was investigated. A time-resolved analysis of all reaction products in the gas, organic and aqueous phase, is given. The organic sulfur in BT is mainly converted to sulfuric acid. Mass transport limitations can be excluded. The reaction orders are 1 with regard to BT, and 0.5 both for HPA-5 and O2. Calculated data derived from this mechanism with a power law kinetic approach show good agreement to the experimental data for conversions below 60 \%. At higher BT conversions, significant deviations are found, suggesting that acidic products formed in the BT oxidation affect the catalyst and therefore the initial kinetics of the BT oxidation.

Selective hydrogenation of glycerol to 1,2-propanediol (1,2-PD) is a promising route for sustainable production of platform chemicals. Herein, a bimetallic RuCu catalyst supported on multiwall carbon nanotubes (RuCu/MWCNT) is reported that shows superior catalytic performance leading to 93.4% 1,2-PD selectivity under mild reactions conditions.

Promising bifunctional catalyst systems composed of platinum and polyoxometalates (POMs) were applied successfully for the selective catalytic hydrogenation of 2,5‐dimethylfuran (DMF) to 2‐hexanol under mild conditions. Pt(acac)2 was found to be the most active Pt precursor for the ring opening of DMF, and the Keggin‐type POM K3[PW12O40] was identified as the most promoting acidic support for 2‐hexanol formation at 80 °C and 10 bar H2 pressure using n‐decane as a carrier liquid. It was revealed that modifications in the synthetic procedure of the Pt/K3[PW12O40] catalytic system allowed its catalytic performance to be enhanced. Thus, a higher yield of 2‐hexanol (72.5%) was achieved compared to that (49%) obtained using a commercial Pt/C catalyst with the same Pt loading. The Wells–Dawson‐type POM containing catalyst Pt/K6[α‐P2W18O62] was found to be selective for 2‐hexanon formation (56.4% yield) under identical reaction conditions. Furthermore, furan and 2‐methylfuran were also selectively hydrogenated to 1‐butanol (59.7% yield) and 1/2‐pentanol (44.3% yield), respectively, under the applied reaction conditions. Moreover, using analytical tools like N2‐physisorption, NH3‐TPD, inductively coupled plasma optical emission spectroscopy (ICP‐OES), CO chemisorption, and transmission electron microscopy (TEM), revealed that the higher total acid site density of the K3[PW12O40] enhances C=O hydrogenation and overcomes the rate‐limiting step of 2‐hexanone hydrogenation to 2‐hexanol. This demonstrates the high performance of the bi‐functional catalyst system Pt/K3[PW12O40] towards ring opening of various furans and the very high selectivity towards alcohol formation. This approach opens new interesting valorization pathways for several furanic compounds with respect to sustainable alcohol formation. © 2021 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

The selective oxidative conversion of seven representative fully characterized biomasses recovered as secondary feedstocks from the agroindustry is reported. The reaction system, known as the “OxFA process,” involves a homogeneous polyoxometalate catalyst (H8PV5Mo7O40), gaseous oxygen, p-toluene sulfonic acid, and water as solvent. It took place at 20 bar and 90 °C and transformed agro-industrial wastes, such as coffee husks, cocoa husks, palm rachis, fiber and nuts, sugarcane bagasse, and rice husks into biogenic formic acid, acetic acid, and CO2 as sole products. Even though all samples were transformed; remarkably, the reaction obtains up to 64, and 55% combined yield of formic and acetic acid for coffee and cocoa husks as raw material within 24 h, respectively. In addition to the role of the catalysts and additive for promoting the reaction, the influence of biomass components (hemicellulose, cellulose and lignin) into biogenic formic acid formation has been also demonstrated. Thus, these results are of major interest for the application of novel oxidation techniques under real recovered biomass for producing value-added products. Graphical abstract

In this study, the performance of an In2O3/ZrO2 catalyst for hydrogenation of CO2 to methanol is reported in the presence of typical impurities of industrial CO2 feed gas streams. Experiments were performed with defined amounts of SO2, H2S, NO2, NH3 and hydrocarbons purposely added to the reaction mixture under industrially relevant conditions (225–275 °C, 50 bar total pressure, H2 : CO2 = 3 : 1). Comparative studies – with and without added impurities – further relate the observed effects to the behaviour of the commercial Cu/ZnO/Al2O3 methanol catalyst under identical treatments. Elemental analysis was used to determine the amount of sulphur, nitrogen and carbon residing on the catalyst after poisoning and after methanol synthesis. Moreover, temperature programmed desorption (TPD), temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) allowed identifying potential catalyst poisons formed on the catalyst surface. This work discloses that H2S and SO2 impurities led to drastic deactivation of the In2O3/ZrO2 catalyst (due to indium sulfide and -sulphate formation), while NH3, NO2 and hydrocarbon impurities have no major effect on the methanol production.

We report the highly remarkable discovery that glucose oxidation catalysed by polyoxometalates (POMs) in methanolic solution enables formation of formic acid and methyl formate in close to 100% combined selectivity, thus with only negligible sugar oxidation to CO2. In detail, we report oxidation of a methanolic glucose solution using H8[PV5Mo7O40] (HPA-5) as catalyst at 90 °C and 20 bar O2 pressure. Experiments with 13C-labelled glucose confirm unambiguously that glucose is the only source of the observed formic acid and methyl formate formation under the applied oxidation conditions. Our results demonstrate a very astonishing solvent effect for the POM-catalysed glucose oxidation. In comparison to earlier work, a step-change in product yield and selectivity is achieved by applying an alcoholic reaction medium. The extremely high combined yields of formic acid and methyl formate greatly facilitate product isolation as low-boiling methyl formate (bp = 32 °C) can simply be isolated from the reaction mixture by distillation.

A liquid core waveguide membrane microreactor is a novel concept that allows in situ spectroscopy to be carried out in an optical microreactor, while enabling a very high gas-to-liquid mass transfer. The potential of this reactor concept to derive kinetics in gas/liquid reactions is demonstrated using the heteropoly acids catalyzed oxidation of biomass to formic acid (the ‘OxFA process’). For vanadium-substituted, Keggin-type heteropoly acids, the kinetics of the reduction and reoxidation step of the catalyst cycle was deduced using in situ UV/Vis spectroscopy. Reduction was studied from 40 to 80 °C: a strong dependency of the reduction kinetics was deduced. In combination with additional cyclic voltammetry and EPR characterization, it can be assumed that two active centers promote this reaction, while the existence and proportions of both types depends on the degree of vanadium substitution. The rapid mass transfer allowed transient response experiments to be carried out for the reoxidation step, which was studied up to 150 °C. Switching from anaerobic to aerobic conditions, an even stronger dependency of the reoxidation kinetics on the degree of vanadium substitution was revealed.

The main objective of this contribution was to optimize the process conditions for a fractionated oxidation of lignocellulosic biomass (e.g., wood) to produce formic acid and cellulose for further ...

Synthesis of bulk chemicals from biogenic resources is gaining increasing interest in industry and academia. In the present study, we demonstrate the continuous production of acrylic acid (AA) from...

Electric fuels (e-fuels) enable CO2-neutral mobility and are therefore an alternative to battery-powered electric vehicles. This paper compares the cost-effectiveness of Fischer-Tropsch diesel, methanol and Liquid Organic Hydrogen Carriers. The production costs of those fuels are to a large part driven by the energy-intensive electrolytic hydrogen production. In this paper, we apply a multi-level electricity market model to calculate future hourly electricity prices for various electricity market designs in Germany for the year 2035. We then assess the economic efficiency of the different fuels under various future market conditions. In particular, we use the electricity price vectors derived from an electricity market model calibrated for 2035 as an input for a mathematical model of the entire process chain from hydrogen production and chemical bonding to the energetic utilization of the fuels in a vehicle. Within this model, we perform a sensitivity analysis, which quantifies the impact of various parameters on the fuel production cost. Most importantly, we consider prices resulting from own model calculations for different energy market designs, the investment cost for the electrolysis systems and the carbon dioxide purchase price. The results suggest that the use of hydrogen, which is temporarily bound to Liquid Organic Hydrogen Carriers, is a favorable alternative to the more widely discussed synthetic diesel and methanol.

Renewable energy sources such as wind and solar power generate fluctuating electric energy. To bridge energy-lean times and to utilize the temporal surplus of electricity production large amounts of energy must be stored. One promising approach is the chemical storage in methanol that is formed from renewable H2 from water electrolysis and CO2. In our contribution we demonstrate a way to increase the methanol yields in CO2 hydrogenation significantly by in situ sorption of methanol and water in alkali salt-doped ionic liquids (ILs). The reaction and product sorption take place in a single reactor vessel which shifts the methanol yield from the thermodynamic equilibrium of 25.3% at 75 bar (H2 : CO2 = 3 : 1) and 250 °C up to 60%.

Our contribution investigates the formation of various catalytically active vanadium species for different glucose transformation reactions. By applying both 51V-NMR (nuclear magnetic resonance) and continuous wave EPR (electron paramagnetic resonance) spectroscopy, we were able to identify the different vanadium species that catalyse glucose transformation to several organic acids in aqueous solution depending on the reaction atmosphere and type of vanadium precursor. Under aerobic conditions (20 bar oxygen atmosphere) we could prove that only the higher-substituted vanadium containing polyoxometalate HPA-5 (H8PV5Mo7O40) catalyses the desired glucose oxidation to formic acid at 90 °C. Moreover, our results suggest that substituted V5+ species are the predominantly catalytic active species in the production of formic acid. Using anaerobic conditions (20 bar nitrogen atmosphere), we could show that different vanadium species are formed depending on the nature of the precursor. Hereby, paramagnetic acid-bound vanadyl species formed from the VOSO4 and NH4VO3 as well as the HPA-5 precursor seem to be predominantly responsible for lactic acid formation from glucose under anaerobic conditions.

A new reaction system for the highly selective, hydrobromic acid catalyzed conversion of lactide into acrylic acid under mild conditions is reported. The applied liquid reaction system consists of a temperature-stable bromide-containing ionic liquid and 2-bromopropionic acid as a source of dry HBr, with no volatile organic solvent being used. This allows for the in situ removal of the formed acrylic acid, leading to an unmatched acrylic acid selectivity of over 72 % at full lactide conversion. Accounting for leftover reaction intermediates on the way to acrylic acid, which could be recycled in an elaborate continuous process, the proposed reaction system shows potential for acrylic acid yields well above 85 % in the liquid phase. This opens new avenues for the effective conversion of biogenic lactic acid (e.g., obtained by fermentation from starch) to acrylic acid. The resulting bio-acrylic acid is a highly attractive product for, for example, the diaper industry, where we expect consumers to be especially sensitive to aspects of sustainability.

Our contribution describes the oxidative desulfurization of dibenzothiophene (DBT) from model oils using an aqueous H8PV5Mo7O40 (HPA-5) catalyst solution and molecular oxygen as the oxidant. In contrast to common oxidative desulfurization (ODS) protocols, the organic sulfur compound DBT is oxidized to water-soluble compounds, such as sulfuric acid (50–55%), sulfoacetic acid (20–25%), and sulfobenzoic acid (25–30%), which are extracted in situ into the aqueous catalyst phase. We describe the activating effect of oxalic acid on the ODS performance of the catalyst and propose a mechanism for the catalyst activation. Moreover, we report on the influence of various organic solvents, i.e., n-alkanes and aromatics, on the oxidative DBT removal. Remarkably, the rate of DBT oxidation and removal enhances with an increasing chain length of the alkane matrix, whereas aromatic compounds in the oil matrix inhibit the desulfurization rate. Moreover, we demonstrate that the aqueous catalyst phase can be reused at least ...

Sustainable production of alcohols from renewable sources represents a very important environmental and industrial technology. In this work, response surface methodology (RSM) was employed to study the influence of various process parameters, such as temperature, pressure and substrate to catalyst ratio on the selective hydrogenation of dimethylfuran (DMF) as a model compound for bio-derived furans. The aim was to maximize the yield of the alcoholic product (2-hexanol) using a bifunctional catalyst system composed of platinum supported on a Keggin-polyoxometalate under mild hydrogenation conditions. Hereby, the RSM was used in order to build four predictive models capable of estimating the yield of each product resulting from the hydrogenation reaction. The performance of the prediction models was examined both statistically and experimentally confirming that the predictions are in an excellent agreement with the experimental data. Numerical optimization was performed to reveal the optimal operating conditions to achieve maximum yield of the alcoholic product. With the help of Design of Experiments (DoE) and desirability function approach for optimization, we were able to achieve 78% 2-hexanol yield at complete DMF conversion using a Pt/K3PW12O40 catalyst under mild hydrogenation conditions of 80°C and 5-15 bar hydrogen pressure.

For the first time, a selective catalytic conversion of thermally induced side products (humins) from biomass valorization to short-chain carboxylic acids like formic acid and acetic acid is reported. Very interestingly, we found that homogeneous polyoxometalate catalysts could selectively oxidize humins from sugar-derived levulinic acid production to formic acid and acetic acid under very mild conditions in a simple monophasic aqueous approach. This green and sustainable process offers a very cost-effective and sustainable way for the conversion of undesired humins and benefits from its low reaction temperature (90-120 °C) and its tunable product distribution. By variation of process parameters and chemical composition of the POM structures, we could control both product selectivity and humin conversion. Furthermore, catalyst recycling over three batches has been successfully carried out.

A detailed kinetic analysis of the selective catalytic oxidation of different biogenic model substrates to formic acid (OxFA process) is presented using two different polyoxometalate catalysts, HPA-2 (H5PV2Mo10O40) and HPA-5 (H8PV5Mo7O40). By using high oxygen pressures (30–60 bar) and temperatures of 80–90 °C in aqueous solution, we were able to investigate the rate-determining substrate oxidation step catalyzed by the oxidized form of the polyoxometalates (POMs) by keeping the concentration of the catalytic active species constant. Under these conditions, kinetic parameters like effective reaction order and reaction rate constants could be determined by the differential method for model substrates like glucose, fructose, sorbitol, and gluconic acid. Furthermore, kinetic experiments using the two different catalysts showed a different behavior for various functionalities within the carbon framework of the substrate with the tendency of higher reaction rates with the HPA-5 catalyst. This effect was more p...

Our contribution demonstrates a new way of fuel desulfurization, namely selective oxidation of organic S-compounds present in fuels to water-soluble sulfur compounds followed by in situ extraction of the latter into an aqueous phase. Different from common oxidative desulfurization (ODS) processes, we demonstrate a technique that converts sulfur compounds in fuel to a large extent to sulfate (60–70%) using oxygen as the oxidant and an aqueous H8PV5Mo7O40 (HPA-5) solution as the catalyst phase. Other water-soluble desulfurization products are sulfoacetic acid (SAA) with a share of 10–20%, 2-sulfobenzoic acid (2-SBA), and 2-(sulfooxy)benzoic acid (2-SOBA), the latter two with a share of

Full cost‐effective exploitation of all wood components is key to growing a commercially successful biorefining industry. An innovative process is reported that combines fractionation of lignocellulosic biomass using a low‐cost ionic liquid (Ionosolv) and production of bio‐derived formic acid using polyoxometalates and molecular oxygen (OxFA process). We show that the hemicellulose and part of the lignin were selectively dissolved into the ionic liquid triethylammonium hydrogen sulfate and oxidised in situ to short‐chain, distillable carboxylic acids by a Keggin‐type polyoxometalate with high yields and selectivities. Characterization by several techniques, including ICP‐OES, FTIR, GC, HPLC and NMR spectroscopy confirmed stability of the catalyst over three consecutive POM‐Ionosolv recycles and stable formic acid yields.High formic acid yields of 26 % (pine chips), 23 % (beech chips), and 18 % (Miscanthus ) were obtained with respect to the initial carbon content of the biomass, with unprecedented oxidation selectivities for formic acid of 54–62 % depending on vanadium substitution in the polyoxometalate, the processing temperature and the water content in the reaction mixture.. We also demonstrate that the cellulose rich pulp is a suitable source of glucose via enzymatic saccharification. We report cellulose yields of 37% for Miscanthus (from originally 48% glucan content), 33% for pine (from originally 49%) and 31% for beech (from originally 41%) were achieved, and a saccharification yield of up to 25% without optimisation. With further optimisation, this concept has the potential to generate two chemical products directly from lignocellulose in high yields and selectivities and hence a novel avenue for full utilisation of cellulose, hemicellulose and lignin.

Supported vanadium-substituted Keggin polyoxometalates (POMs) were applied as catalysts for the selective catalytic reduction of NO using NH3 as reductant (NH3-SCR). Interestingly, HPA-3 (H6PV3Mo9O40) was found to be the most active catalytic species, and TiO2 (anatase) the most promoting support for the SCR reaction in the temperature range 200-350 C. Moreover, 10 wt.% HPA 3 loading was found to be optimum resulting in nearly complete NO conversion at 350 °C. Characterization by several techniques, including N2-physisorption, NH3-TPD, FTIR, XPS and TEM showed distinctive structural HPA-3 support interactions explaining the beneficial interplay between both parts for the SCR reaction. Furthermore, different catalytically active surface species were identified at various reaction temperatures and SCR conditions by in-situ EPR spectroscopy. The study introduces a novel type of heterogeneous supported vanadium-based NH3-SCR catalysts comprising redox-active POMs, which so far mainly have been applied for homogeneously catalyzed reactions.

The use of electric fuels (e-fuels) enables CO2-neutral mobility and opens therefore an alternative to fossil-fuel-fired engines or battery-powered electric motors. This paper compares the cost-effectiveness of Fischer-Tropsch diesel, methanol, and hydrogen stored as cryogenic liquid (LH2) or in form of liquid organic hydrogen carriers (LOHCs). The production cost of those fuels are to a large extent driven by the energy-intensive electrolytic water splitting. The option of producing e-fuels in Germany competes with international locations with excellent conditions for renewable energy harvesting and thus very low levelized cost of electricity. We developed a mathematical model that covers the entire process chain. Starting with the production of the required resources such as fresh water, hydrogen, carbon dioxide, carbon monoxide, electrical and thermal energy, the subsequent chemical synthesis, the transport to filling stations in Germany and finally the energetic utilization of the fuels in the vehicle. We found that the choice of production site can have a major impact on the mobility cost using the respective fuels. Especially in case of diesel production, the levelized cost of electricity driven by the full load hours of the applied renewable energy source have a huge impact. An LOHC-based system is shown to be less dependent on the kind of electricity source compared to other technologies due to its comparatively low electricity consumption and the low cost for the hydrogenation units. The length of the transportation route and the price of the filling station infrastructure, on the other hand, clearly increase mobility cost for LOHC and LH2.

Herein, the possibility of generating Raney‐Copper catalysts with high geometric complexity is demonstrated. For this, periodic open cellular structures (POCS) composed of a highly brittle Al–Cu alloy containing 29.4 at% copper are fabricated by selective electron beam melting (SEBM) for application in chemical reaction engineering. After selective leaching of aluminum in an NaOH solution, the POCS show a core–shell structure with a nanoporous copper surface layer and a solid core. The fabrication and dealloying processes as well as the microstructure are studied. Moreover, the SEBM‐processed Raney‐type copper catalysts show a high catalytic activity in methanol synthesis.

In this work we combined kinetic studies for aqueous-phase glucose oxidation in a high-pressure autoclave setup with catalyst reoxidation studies in a liquid-core waveguide membrane reactor. Hereby, we investigated the influence of Nb- and Ta-doping on Mo-based Keggin-polyoxometalates for both reaction steps independently. Most importantly, we could demonstrate a significant increase of glucose oxidation kinetics by Ta- and especially Nb-doping by factors of 1.1 and 1.5 compared to the classical HPA-Mo. Moreover, activation energies for the substrate oxidation step could be significantly reduced from around 80 kJ mol−1 for the classical HPA-Mo to 61 kJ mol−1 for the Ta- and 55 kJ mol−1 for the Nb-doped species, respectively. Regarding catalyst reoxidation kinetics, the doping did not show significant differences between the different catalysts.

A Ru-doped phospho-tungstic Wells&ndash, Dawson polyoxometalate (POM) was successfully applied as homogeneous catalyst for glycerol hydrogenolysis in aqueous media. The synthesized compound showed superior catalytic activity compared to classical homogeneous/heterogeneous Ru catalysts like RuCl3 and Ru/C under identical reaction conditions, whereas the analogous POM doped with Pd or Pt proved far less activity. Detailed characterization of the POMs was performed using 31P-NMR to identify characteristic phosphorous peaks of the heteroatoms, infrared spectroscopy (ATR-FTIR) to confirm characteristic P-O and W-O-W vibrations, powder XRD for comparison of crystal structures, and X-ray fluorescence (XRF) and inductive-coupled plasma (ICP) analysis to determine elemental composition. Variation of the reaction parameters for the best performing Ru-doped POM catalyst showed that substrate concentration played an important role for both product selectivity and conversion. Moreover, medium hydrogen pressure and high stirring speed were key factors to obtain highly selective conversion of glycerol to 1,2-propanediol.