At high temperatures, the oxidative coupling of methane (OCM) is an attractive approach for catalytic conversion of methane into value-added chemicals. Experiments with a Pt/Al₂O₃-coated catalytic honeycomb monolith were conducted with varying CH₄/O₂ ratios, N₂ dilution at atmospheric pressure, and very short contact times. The reactor was modeled by a multiscale approach using a parabolic two-dimensional flow field description in the monolithic channels coupled with a heat balance of the monolithic structure, and multistep surface reaction mechanisms as well as elementary-step, gas phase reaction mechanisms. The contribution of heterogeneous and homogeneous reactions, both of which are important for the optimization of C₂ products, is investigated using a combination of experimental and computational methods. The oxidation of methane, which takes place over the platinum catalyst, causes the adiabatic temperature increase required for the generation of CH₃ radicals in the gas phase, which are essential for the formation of C₂ species. Lower CH₄/O₂ ratios result in higher C₂ selectivity. However, the presence of OH radicals at high temperatures facilitates subsequent conversion of C₂H₂ at a CH₄/O₂ ratio of 1.4. Thereby, C₂ species selectivity of 7% was achieved at CH₄/O₂ ratio of 1.6, with 35% N₂ dilution.

In this work, the influence of the structure-forming agent on the composition, morphology and oxygen reduction reaction (ORR) activity of Fe-N-C catalysts was investigated. As structure-forming agents (SFAs), dicyandiamide (DCDA) (nitrogen source) or oxalic acid (oxygen source) or mixtures thereof were used. For characterization, cyclic voltammetry and rotating disc electrode (RDE) experiments were performed in 0.1 M H₂SO₄. In addition to this, N₂ sorption measurements and Raman spectroscopy were performed for the structural, and elemental analysis for chemical characterization. The role of metal, nitrogen and carbon sources within the synthesis of Fe-N-C catalysts has been pointed out before. Here, we show that the optimum in terms of ORR activity is achieved if both N- and O-containing SFAs are used in almost similar fractions. All catalysts display a redox couple, where its position depends on the fractions of SFAs. The SFA has also a strong impact on the morphology: Catalysts that were prepared with a larger fraction of N-containing SFA revealed a higher order in graphitization, indicated by bands in the 2nd order range of the Raman spectra. Nevertheless, the optimum in terms of ORR activity is obtained for the catalyst with highest D/G band ratio. Therefore, the results indicate that the presence of an additional oxygen-containing SFA is beneficial within the preparation.

Gas-phase synthesis and detection of boron-doped nitride clusterfullerenes and a large variety of monometallofullerenes have been achieved using a pulsed laser vaporization cluster source. Density functional theory (DFT) calculations show that the electronic structures of boron-doped endohedral metallofullerenes differ from those of the pristine all-carbon cages due to the lack of one electron upon boron substitution. For monometallofullerenes, this is likely the main reason for the somewhat different abundance distribution observed for boron-doped with respect to all-carbon cages. Moreover, the three carbon atoms directly bonded to B show the most negative charges in the cage, and consequently, metal atoms are primarily placed nearby boron.

The effect of rare earth oxides as dopants on the Pt‐governed oxidative coupling of methane (Pt‐OCM) is investigated. The addition of 20 wt.‐% of La‐, Nd‐, Sm‐, and Pr‐oxides to the support benefits the C₂ product selectivity and offers the potential to enhance the catalyst stability. Compared to the reference catalyst Pt/Al₂O₃, the addition of Sm₂O₃ increased the total selectivity by up to 23 %. Furthermore, La₂O₃ addition was found beneficial with respect to the (thermal) stability of the catalyst. Dopant content variations uncovered that the catalyst formulation with 20 wt.‐% La₂O₃ represents an optimum regarding performance and stability.

Autothermal oxidative coupling of methane (OCM) is a highly attractive approach for methane utilization. If platinum-based catalysts are operated in short-contact-time reactors with high space velocities, high methane conversion can be achieved. Using a 1 wt.% Pt/Al₂O₃ catalyst as a benchmark, the present study elucidates how different dopants, namely Ni, Sn, and V₂O₅, affect the OCM reaction. Kinetic catalyst tests reveal that acetylene (C₂H₂) is the predominant C₂ product, irrespective of the catalyst formulation or operation conditions. Furthermore, the use of bimetallic catalysts allows either for the maintenance or even the improvement of the C₂ selectivity during OCM, which is attributed to synergistic effects that occur when expensive Pt is partially replaced by cheaper dopants. In particular, the 1 wt.% Pt/Al₂O₃ reference catalyst yielded a maximum C₂ selectivity of 8.2%, whereas the best-performing doped sample 0.25 wt.% Pt 0.75 wt.% V₂O₅/Al₂O₃ yielded a total C₂ selectivity of 11.3%.