A stochastic search of the potential energy surface for the formic acid dimers results in 21 well-defined minima. A number of structures are reported here for the first time, others have already been experimentally detected or computationally predicted. Four types of different hydrogen bonds (HBs) are at play stabilizing the clusters: primary C=O⋯ H—O and H—O⋯ H—O and secondary C=O⋯ H—C and H—O⋯ H—C HBs corresponding to well-characterized bonding paths are identified. A novel C=O⋯ C stabilizing interaction is also reported. The double proton transfer reaction is calculated to occur in a synchronous fashion, with an energy barrier smaller than the energy needed to break up the dimers.

Perovskite-like oxides present huge chemical variability and a wide range of applications as catalysts for oxidation reactions. The interaction of several small gas molecules with the surface of LaCoO₃ and LaMnO₃ perovskite-like oxides was studied by Near Ambient Pressure X-ray photoelectron spectroscopy (NAP-XPS) and CO Temperature Programmed Desorption (CO-TPD). Surface chemical changes such as the O_surf/O_lattice and cation B oxidation state ratios were analyzed as a function of temperature (400 K, 450 K, 500 K, 550 K, and 650 K) under different gas atmospheres like Ar, CO, H₂, and O₂. It was found that there was a partial surface reduction when H₂ and CO were used in the reaction, and therefore, the cation B oxidation state (Mn⁴⁺/Mn³⁺ and Co³⁺/Co²⁺) ratio decreased. Under the CO stream, carbonate species were formed, presenting a C1s signal between 284.5 eV and 287 eV. The CO₂ evolution during the reaction at temperatures greater than 500 K was associated with CO activation over or near to surface oxygen species. A Mars-van Krevelen mechanism was proposed for the process, finding significant differences between LaCoO₃ and LaMnO₃ perovskite-like solid catalysts behavior. Graphical Abstract

A crucial characteristic of perovskite-like oxides is oxygen mobility, which can be enhanced by inducing structural defects through stoichiometry variations during synthesis, thereby boosting the catalytic activity. This study evaluated the effect of structural modifications of LaFeO₃ (LF) and LaMnO₃ (LM) perovskites series on the total oxidation of 2-propanol as a VOC model, a well-known organic solvent. These modifications were performed during synthesis by partially removing the B-site cation or by structural doping in the B-site with another cation (Mn for the LF series and Pd for the LM series). Structural characterization was carried out by XRD and Raman spectroscopy, while the bulk and surface chemical composition were assessed by ICP and XPS, respectively. On the other hand, catalytic activity was performed using a reactivity test with the 2-propanol molecule. The CO-TPR and O₂-TPD measurements were used to characterize the reducibility of the active phase, and the type of oxygen species present in the sample. The catalytic activity results indicated that the modified perovskites showed a difference of 118 °C and 109 °C in the T₉₅ parameter (Temperature at which the conversion of 2-propanol was 95%) relative to pure LF and LM perovskites, respectively. It was also observed that the inclusion of cationic species with high oxidation states enhances the catalytic properties of the materials not only for the doped perovskites but also for the impregnated ones used for comparison purposes. This research demonstrated that stoichiometric variations in modified perovskite-like catalysts significantly improve the catalytic capacity by forming structural defects and modifying redox properties.Kindly check and confirm whether the corresponding author is correctly identified.I confirm that the corresponding author is well identified Graphical Abstract

Due to their weak polarity and large surface area, activated carbon supports have the potential to enhance the dispersion of metal-sulfides. It is expected that the absence of a strong metal-support interaction can result in the formation of a very active and stable Ni-Mo-S phase. In this study, catalysts with different amounts of nickel and molybdenum supported on a commercial activated carbon were prepared by a co-impregnation method and characterized by BET, XRF, and SEM techniques. The catalytic activity for hydroprocessing of Jatropha oil was evaluated in a batch reactor, and the composition of the liquid and gaseous products were determined. Results showed that gaseous products are mainly composed of high amounts of propane and small amounts of other light hydrocarbons (C1 to C5). Liquid hydrocarbon products consisted of a mixture containing mainly n-paraffins of C15-C18 and some oxygenated compounds. The catalysts with a mass fractionof 3 % Ni, 15 % Mo (Ni3Mo15/AC) presented the highest selectivity toward C17-C18 hydrocarbons, with a product distribution similar to a commercialalumina-supported Ni-Mo-S catalyst.