Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative 13C nuclear magnetic resonance (13C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. 13C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cake-based bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil.

The electrocatalytic oxygen evolution reaction (OER) presents the key transformation in electrochemical water‐splitting majorly determining energy efficiency and economics of hydrogen generation. In this study, the kinetics of the OER over Ni−Co oxide structured by KIT‐6 templating and non‐structured Ni−Co oxide catalysts in alkaline solution have been investigated aiming for insight with regard to the respective kinetically relevant surface reactions. Steady‐state Tafel plot analysis and electrochemical impedance spectroscopy (EIS) were used to determine kinetic parameters, Tafel slopes and the order of reaction. A dual Tafel slope behavior was observed for both catalysts. Tafel slopes of ca. 40 and 120 mV dec−1 and 90 and 180 mV dec−1 at low and high overpotentials appear for structured and non‐structured Ni−Co oxide, respectively. A reaction order of unity was observed for structured Ni−Co oxide, while non‐structured Ni−Co oxide possessed a fractional reaction order in the high overpotential region. The kinetics of OER over structured Ni−Co oxide were governed by Langmuir adsorption with the rate‐limiting step after primary adsorption of surface intermediates. In contrast, non‐structured Ni−Co oxide obeyed the Temkin adsorption isotherm condition with the primary adsorption step being rate‐limiting.

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The aqueous Ru/C-catalyzed hydrogenolysis of biomass-based polyols such as erythritol, xylitol, sorbitol, and cellobitol is studied under neutral and acidic conditions. For the first time, the complete product spectrum of C2 C6 polyols is identified and, based on a thorough analysis of the reaction mixtures, a comprehensive reaction mechanism is proposed, which consists of (de)hydrogenation, epimerization, decarbonylation, and deoxygenation reactions. The data reveal that the Ru-catalyzed deoxygenation reaction is highly selective for the cleavage of terminal hydroxyl groups. Changing from neutral to acidic conditions suppresses decarbonylation, consequently increasing the selectivity towards deoxygenation.

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Many industrially important chemical transformations occur at the interface between a solid catalyst and liquid reactants. In situ and operando spectroscopies offer unique insight into the reactivity of such catalytically active solid–liquid interfaces.

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