Flexibilization of Biorefineries: Tuning Lignin Hydrogenation by Hydrogen Partial Pressure

Significant Roles of Surface Hydrides in Enhancing the Performance of Cu/BaTiO2.8 H0.2 Catalyst for CO2 Hydrogenation to Methanol

Tuning the anionic site of catalyst supports can impact reaction pathways by creating active sites on the support or influencing metal-support interactions when using supported metal nanoparticles. This study focuses on CO2 hydrogenation over supported Cu nanoparticles, revealing a 3-fold increase in methanol yield when replacing oxygen anions with hydrides in the perovskite support (Cu/BaTiO2.8 H0.2 yields ~146 mg/h/gCu vs. Cu/BaTiO3 yields ~50 mg/h/gCu). The contrast suggests that significant roles are played by the support hydrides in the reaction. Temperature programmed reaction and isotopic labelling studies indicate that BaTiO2.8 H0.2 surface hydride species follow a Mars van Krevelen mechanism in CO2 hydrogenation, promoting methanol production. High-pressure steady-state isotopic transient kinetic analysis (SSITKA) studies suggest that Cu/BaTiO2.8 H0.2 possesses both a higher density and more active and selective sites for methanol production compared to Cu/BaTiO3 . An operando high-pressure diffuse reflectance infrared spectroscopy (DRIFTS)-SSITKA study shows that formate species are the major surface intermediates over both catalysts, and the subsequent hydrogenation steps of formate are likely rate-limiting. However, the catalytic reactivity of Cu/BaTiO2.8 H0.2 towards the formate species is much higher than Cu/BaTiO3 , likely due to the altered electronic structure of interface Cu sites by the hydrides in the support as validated by density functional theory (DFT) calculations.

Trash-to-fuel: Converting municipal waste into transportation fuels by pyrolysis

In daily life humankind is producing a significant amount of garbage, creating a great environmental concern. However, garbage consists of high amounts of carbon based materials, making it a very useful resource. An easy way to use it is to produce transport fuels obtained through pyrolysis. Multiple plastic waste materials were investigated here. Thermogravimetric analysis (TGA) of individual polymers shows that almost complete conversion could be achieved. More than 70% liquid fuels were derived from pyrolysis of polypropylene, polystyrene at 450°C, and low-/high-density polyethylene at 500°C. Using gas chromatography/high-resolution mass spectrometry (GC/HR-MS) allows studying the thermal transformation and proposing a mechanism. An examination of carbon number distribution reveals the potential of plastic liquid fuels, which can be used as an alternative to partial substitution of fossil-fuel-derived gasoline and diesel fuel and also provides a final use of polymer materials, which otherwise would be deposited on waste dumps.

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Development of pyrolysis reactor to convert municipal waste to transportation fuels

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Studying the reaction parameters of a set of different individual polymer materials

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Development of a reaction and degradation mechanism

Studying the Complexity of Biomass Derived Biofuels

Biofuel produced from biomass pyrolysis is a good example of a highly complex mixture. Detailed understanding of its composition is a prerequisite for optimizing transformation processes and further upgrading conditions. The major challenge in understanding the composition of biofuel derived from biomass is the wide range of compounds with high diversity in polarity and abundance that can be present. In this work, a comprehensive analysis using mass spectrometry is reported. Different operation conditions are studied by utilizing multiple ionization methods (positive mode atmospheric pressure photo ionization (APPI), atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) and negative mode ESI) and applying different resolving power set-ups (120 k, 240 k, 480 k and 960 k) and scan techniques (full scan and spectral stitching method) to study the complexity of a pyrolysis biofuel. Using a mass resolution of 960 k and the spectral stitching scan technique gives a total of 21,703 assigned compositions for one ionization technique alone. The number of total compositions is significantly expanded by the combination of different ionization methods.