The “Seven Pillars” of oxidation catalysis proposed by Robert K. Grasselli represent an early example of phenomenological descriptors in the field of heterogeneous catalysis. Major advances in the theoretical description of catalytic reactions have been achieved in recent years and new catalysts are predicted today by using computational methods. To tackle the immense complexity of high-performance systems in reactions where selectivity is a major issue, analysis of scientific data by artificial intelligence and data science provides new opportunities for achieving improved understanding. Modern data analytics require data of highest quality and sufficient diversity. Existing data, however, frequently do not comply with these constraints. Therefore, new concepts of data generation and management are needed. Herein we present a basic approach in defining best practice procedures of measuring consistent data sets in heterogeneous catalysis using “handbooks”. Selective oxidation of short-chain alkanes over mixed metal oxide catalysts was selected as an example.

Cation substitution in transition metal oxides is an important approach to improve electrocatalysts by the optimization of their composition. Herein, we report on phase-pure spinel-type CoV2-xFexO4 nanoparticles with 0 ≤ x ≤ 2 as a new class of bi-functional catalysts for the oxygen evolution (OER) and oxygen reduction reactions (ORR). The mixed-metal oxide catalysts exhibit high catalytic activity for both OER and ORR that strongly depends on the V and Fe content. CoV2O4 is known to exhibit a high conductivity, while in CoFe2O4 the cobalt cation distribution is expected to change due to the inversion of the spinel structure. The optimised catalyst, CoV1.5Fe0.5O4, shows an overpotential for OER of ~300 mV for 10 mA cm-2 with a Tafel slope of 38 mV dec-1 in alkaline electrolyte. DFT+U+SOC calculations on cation ordering confirm the tendency towards the inverse spinel structure with increasing Fe concentration in CoV2-xFexO4 that starts to dominate already at low Fe contents. The theoretical results also show that the variation of oxidation states are related to the surface region, where the redox activity was found experimentally to be manifested in the transformation of V3+ → V2+. The high catalytic activity, facile synthesis, and low cost of the CoV2-xFexO4 nanoparticles render them very promising for application in bifunctional electrocatalysis

We present an analytical route toward a detailed and quantitative description of individual defects in heterogeneous catalysts. The investigation is based on a high resolution scanning transmission electron microscopy (STEM) study using complex (Mo,V)O_x mixed oxide as an example. Tiling the structural regions simplifies the identification of local modifications in the microstructure. Up to 19 different structures were observed that can be listed and classified into different structural motifs, intergrowth, channels, interstitial regions, and inclinations. The observed defects are expressed by the rearrangement of the {(Mo)Mo₅O₂₇} building blocks, exhibit different sizes, penetrate the bulk, and can form decoupled surface regions that partially cover the crystallographic bulk. The evaluation of 31 crystals yields an average defect concentration of 3.3% and indicates the absence of identical particles. We have, for example, observed 54 of these rearranged structures close to the surface of one (Mo,V)O_x particle (100 × 50 nm²). A detailed analysis of the atomic arrangement at the surface of this particle suggests a surface composition of (Mo₆₁₀V₂₃₀M₇₀)O_x (M = Mo and/or V). The resulting catalog of motifs reproduces individual fragments of the real structure of a catalyst and can reveal detailed defect−activity correlations that will contribute to a better understanding of heterogeneous catalysis

The bulk crystal structure of an oxidation catalyst as the most popular descriptor in oxidation catalysis is not solely responsible for catalytic performance.

We present an effective procedure to differentiate instrumental artefacts, such as parasitic ions, memory effects, and real trace impurities contained in inert gases. Three different proton transfer reaction mass spectrometers were used in order to identify instrument-specific parasitic ions. The methodology reveals new nitrogen-and metalcontaining ions that up to date have not been reported. The parasitic ion signal was dominated by [N 2 ]H + and [NH 3 ]H + rather than by the common ions NO + and O 2 + . Under dry conditions in a proton transfer reaction quadrupole interface time-of-flight mass spectrometer (PTR-QiTOF), the ion abundances of [N 2 ]H + were elevated compared with the signals in the presence of humidity. In contrast, the [NH 3 ]H + ion did not show a clear humidity dependency. On the other hand, two PTR-TOF1000 instruments showed no significant contribution of the [N 2 ]H + ion, which supports the idea of [N 2 ]H + formation in the quadrupole interface of the PTR-QiTOF. Many new nitrogen-containing ions were identified, and three different reaction sequences showing a similar reaction mechanism were established. Additionally, several metal-containing ions, their oxides, and hydroxides were formed in the three PTR instruments. However, their relative ion abundancies were below 0.03% in all cases. Within the series of metal-containing ions, the highest contribution under dry conditions was assigned to the [Fe(OH) 2 ]H + ion. Only in one PTR-TOF1000 the Fe + ion appeared as dominant species compared with the [Fe(OH) 2 ]H + ion. The present analysis and the resulting database can be used as a tool for the elucidation of artefacts in mass spectra and, especially in cases, where dilution with inert gases play a significant role, preventing misinterpretations. KEYWORDS artefacts, industrial gases, parasitic ions, proton transfer reaction time-of-flight mass spectrometry, volatile organic compounds 1 | INTRODUCTION In the last decades, chemical ionization mass spectrometry (CIMS) 1,2 was established as a new and powerful tool for the on-line monitoring of trace amounts of volatile organic compounds (VOCs) without requiring additional pre-separation techniques such as gas chromatography. One of the important improvements of CIMS was the use of the hydronium (H 3 O + ) cation as primary ionization ion, which has led