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Exploitation of hydrogen as an energy carrier requires the development of systems for its storage and delivery. Formic acid has been proposed as valuable hydrogen carrier compound, due to its relatively high hydrogen content (53 g L−1), the latter being easily and cleanly released in catalytic reactions under mild conditions (HCOOH → H2+ CO2). Ionic liquids are interesting solvents for homogeneous catalyzed formic acid decomposition systems as their extremely low volatility avoids solvent contamination of the produced hydrogen stream. In this paper an outstandingly simple, robust and active catalyst system is presented, namely RuCl3dissolved in 1-ethyl-2,3-dimethylimidazolium acetate (RuCl3/[EMMIM][OAc]). This system proved to be fully recyclable over 10 times. Turnover frequencies (TOF) of 150 h−1and 850 h−1were obtained at 80 °C and 120 °C, respectively. [ABSTRACT FROM AUTHOR]

A new vision of using carbon dioxide (CO2) catalytic processing of oleic acid into C8–C15 alkanes over a nano-nickel/zeolite catalyst is reported in this paper. The inherent and essential reasons which make this achievable are clearly resolved by using totally new catalytic reaction pathways of oleic acid transformation in a CO2 atmosphere. The yield of C8–C15 ingredients reaches 73.10 mol% in a CO2 atmosphere, which is much higher than the 49.67 mol% yield obtained in a hydrogen (H2) atmosphere. In the absence of an external H2 source, products which are similar to aviation fuel are generated where aromatization of propene (C3H6) oxidative dehydrogenation (ODH) involving CO2 and propane (C3H8) and hydrogen transfer reactions are found to account for hydrogen liberation in oleic acid and achieve its re-arrangement in the final alkane products. The reaction pathway in the CO2 atmosphere is significantly different from that in the H2 atmosphere, as shown by the presence of 8-heptadecene, γ-stearolactone, and 3-heptadecene as reaction intermediates, as well as a CO formation pathway. Because of the highly dispersed Ni metal center on the zeolite support, H2 spillover is observed in the H2 atmosphere, which inhibits the production of short-chain alkanes and reveals the inherent disadvantage of using H2. The CO2 processing of oleic acid described in this paper will significantly contribute to future CO2 utilization chemistry and provide an economical and promising approach for the production of sustainable alkane products which are similar to aviation fuel. [ABSTRACT FROM AUTHOR]

Methanol is an important H-carrier and C1 chemical feedstock. In this paper, a direct conversion of methanol to n-C4H10 and H2 was achieved for the first time in a dielectric barrier discharge (DBD) non-thermal plasma reactor. The selective formation of n-C4H10 by limiting COx (x = 1 and 2) generation was obtained by optimizing different plasma processing parameters including the methanol inlet concentration, discharge power, and pre-heating temperature. The results showed that a higher methanol inlet concentration and a higher pre-heating temperature favors the formation of n-C4H10, while a higher methanol inlet concentration and a lower discharge power can effectively limit the formation of CO. The optimal selectivity for n-C4H10 (37.5%), H2 (28.9%) and CO (14%) was achieved, with a methanol conversion of 40.0%, at a methanol inlet concentration of 18 mol%, a discharge power of 30 W and a pre-heating temperature of 140 °C using N2 as a carrier gas. Value-added liquid chemicals (e.g., alcohols, acids, and heavy hydrocarbons) were also obtained from this reaction. Emission spectroscopy diagnostics reveals the formation of various reactive species (e.g., CH, C2, CN, H and metastable N2) in the CH3OH/N2 DBD. Possible reaction pathways for the formation of n-C4H10 were proposed and discussed. [ABSTRACT FROM AUTHOR]

Exploitation of hydrogen as an energy carrier requires the development of systems for its storage and delivery. Formic acid has been proposed as valuable hydrogen carrier compound, due to its relatively high hydrogen content (53 g L−1), the latter being easily and cleanly released in catalytic reactions under mild conditions (HCOOH → H2 + CO2). Ionic liquids are interesting solvents for homogeneous catalyzed formic acid decomposition systems as their extremely low volatility avoids solvent contamination of the produced hydrogen stream. In this paper an outstandingly simple, robust and active catalyst system is presented, namely RuCl3 dissolved in 1-ethyl-2,3-dimethylimidazolium acetate (RuCl3/[EMMIM][OAc]). This system proved to be fully recyclable over 10 times. Turnover frequencies (TOF) of 150 h−1 and 850 h−1 were obtained at 80 °C and 120 °C, respectively. [ABSTRACT FROM AUTHOR]

Pyrolysis oils are the cheapest liquid fuel derived from lignocellulosic biomass. However, pyrolysis oils are a very poor quality liquid fuel that cannot be used in conventional diesel and internal combustion engines. In this paper we show that hydrogen, alkanes (ranging from C1to C6) and polyols (ethylene glycol, 1,2-propanediol, 1,4-butanediol) can be produced from the aqueous fraction of wood-derived pyrolysis oils (bio-oils). The pyrolysis oil was first phase separated into aqueous and non-aqueous fraction by addition of water. The aqueous phase of bio-oil contained sugars; anhydrosugars; acetic acid; hydroxyacetone; furfural and small amounts of guaiacols. The aqueous fraction was subjected to a low temperature hydrogenation with Ru/C catalyst at 125–175 °C and 68.9 bar. The hydrogenation step converts the various functionalities in the bio-oil (including aldehydes; acids; sugars) to corresponding alcohols. Undesired methane and light gases are also produced in this low-temperature hydrogenation step. Diols (ranging from C2 to C4) and sorbitol are obtained as major products in this step. After the low temperature hydrogenation step either hydrogen or alkanes can be produced by aqueous-phase reforming (APR) or aqueous-phase dehydration/hydrogenation (APD/H) respectively. APR was done with a 1 wt% Pt/Al2O3catalyst at 265 °C and 55.1 bar. Hydrogen selectivities of up to 60% were observed. The hydrogen selectivity was a function of space velocity. A 4 wt% Pt/SiO2-Al2O3catalyst at 260 °C and 51.7 bar was used for alkane production by APD/H. The carbon conversion to gas phase products of 35% with alkane selectivity of 45% was obtained for a WHSV of 0.96 h−1when hydrogen is produced in situfrom bio-oil. Alkane selectivity can be improved by supplying hydrogen externally. Alkane selectivities as high as 97% can be obtained when HCl is added to the aqueous-phase of the bio-oil and hydrogen is supplied externally. Model compounds for further bio-oil conversion studies are suggested. [ABSTRACT FROM AUTHOR]

Correction for 'Mo-Doped/Ni-supported ZnIn2S4-wrapped NiMoO4 S-scheme heterojunction photocatalytic reforming of lignin into hydrogen' by Hang Su et al., Green Chem., 2022, DOI: 10.1039/d1gc04397h. [ABSTRACT FROM AUTHOR]