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The hydrogenation of amides is an important but highly challenging reaction, which usually is applied under drastic conditions (temperature >160 °C). Here, we report a heterogeneous Pt–MoOx/TiO2catalyst for amide and imide hydrogenation under milder conditions. The catalytic reactivity is proposed to originate from the synergistic effect between surface active species. Pt promotes formation of partially reduced MoOxthat is responsible for CO activation, and MoOx-modified Pt can more efficiently generate surface species from gas-phase H2. This catalyst system enables the selective hydrogenation of several 2° and 3° amides as well as imides.

Controlling the precise atomic architecture of supported metals is central to optimizing their catalytic performance, as recently exemplified for nanostructured platinum and ruthenium systems in acetylene hydrochlorination, a key process for vinyl chloride production. This opens the possibility of building on historically established activity correlations. In this study, we derived quantitative activity, selectivity and stability descriptors that account for the metal-dependent speciation and host effects observed in acetylene hydrochlorination. To achieve this, we generated a platform of Au, Pt, Ru, Ir, Rh and Pd single atoms and nanoparticles supported on different types of carbon and assessed their evolution during synthesis and under the relevant reaction conditions. Combining kinetic, transient and chemisorption analyses with modelling, we identified the acetylene adsorption energy as a speciation-sensitive activity descriptor, further determining catalyst selectivity with respect to coke formation. The stability of the different nanostructures is governed by the interplay between single atom–support interactions and chlorine affinity, promoting metal redispersion or agglomeration, respectively.

Propane dehydrogenation (PDH) to propene is an important alternative to oil-based cracking processes, to produce this industrially important platform chemical1,2. The commercial PDH technologies utilizing Cr-containing (refs. 3,4) or Pt-containing (refs. 5–8) catalysts suffer from the toxicity of Cr(vi) compounds or the need to use ecologically harmful chlorine for catalyst regeneration9. Here, we introduce a method for preparation of environmentally compatible supported catalysts based on commercial ZnO. This metal oxide and a support (zeolite or common metal oxide) are used as a physical mixture or in the form of two layers with ZnO as the upstream layer. Supported ZnOxspecies are in situ formed through a reaction of support OH groups with Zn atoms generated from ZnO upon reductive treatment above 550 °C. Using different complementary characterization methods, we identify the decisive role of defective OH groups for the formation of active ZnOxspecies. For benchmarking purposes, the developed ZnO–silicalite-1 and an analogue of commercial K–CrOx/Al2O3were tested in the same setup under industrially relevant conditions at close propane conversion over about 400 h on propane stream. The developed catalyst reveals about three times higher propene productivity at similar propene selectivity.

To date, a great number of various materials have been tested for the oxidative coupling of methane (OCM). On the basis of previous statistical analysis of OCM-related literature data, we developed novel catalysts based on K2MnO4or KMnO4supported on SiO2showing selectivity to C2-hydrocarbons (C2H4and C2H6) up to 68 or 66%. The analysis of catalysts containing the single components (Mn/SiO2, K2O/SiO2or SiO2) demonstrates that the co-existence of K and Mn is essential for achieving high selectivity to the desired products. The selectivity can be additionally improved when the OCM reaction is performed in the presence of water. The positive effect of water is attributed to the suppressed direct oxidation of CH4to CO2. Water also enhances the rates of methane conversion into C2-hydrocarbons and CO. Besides, the effects of water are more pronounced for samples based on crystalline SiO2rather than amorphous SiO2. Transient experiments with isotopically labelled oxygen suggest that the accelerating effect should be of heterogenous nature. As the positive influence of water on the selective methane oxidation to C2-hydrocarbons has been established over different catalysts, it may be advantageous to consider it when developing novel materials for the OCM reaction and even for other oxidation reactions.

The impact of formaldehyde (HCHO, formed in vehicle exhaust gases by incomplete combustion of fuel) on the performance of a commercial V2O5-WO3/TiO2catalyst in NH3-SCR of NOxunder dry conditions has been analyzed in detail by catalytic tests, in situ FTIR and transient studies using temporal analysis of products (TAP). HCHO reacts preferentially with NH3to a formamide (HCONH2) surface intermediate. This deprives NH3partly from its desired role as a reducing agent in the SCR and diminishes NO conversion and N2selectivity. Between 250 and 400 °C, HCONH2decomposes by dehydration (major pathway) and decarbonylation (minor pathway) to liberate toxic HCN and CO, respectively. HCN was proven to be oxidized by lattice oxygen of the catalyst to CO2and NO, which enters the NH3-SCR reaction.

Non-oxidative dehydrogenation (DH) of propane, n-butane, and isobutane was investigated over bare ZrO2and binary MZrOx(M = Li, Ca, Mg, Y, Sm or La) materials. Selected samples were characterized by XRD, Raman spectroscopy, NH3temperature-programmed desorption, IR spectroscopy and O2titration experiments. A correlation between the rate of olefin formation and the concentration of anion vacancies formed upon reductive catalyst treatment was established. Such defects represent the catalytically active sites, which are coordinatively unsaturated Zr4+(Zrcus) cations. From a structural viewpoint, the active Zrcussites should have a lower coordination number than the Zrcussites located on the top of an ideal flat surface, thus highlighting the importance of surface defects in the target reactions. However, the intrinsic activity of such sites and/or their concentration depends on the kind of dopant for ZrO2. The dopant was also shown to inhibit side reactions especially those leading to coke due to reducing the concentration of strong acidic sites related to ZrO2. Similar to an analogue of industrial K-CrOx/Al2O3catalyst, all binary catalysts exhibited low activity for consecutive reactions of the target olefins; the desired selectivity was higher than 85% at an alkane conversion of about 30%. With respect to the feed alkane, primary selectivity (at a zero degree of alkane conversion) to the target olefin decreases in the order: C3H8, iso-C4H10, and n-C4H10. This was explained by the higher stability of surface intermediates formed from the latter two contributing to the formation of coke and 1,3-butadiene, respectively.

This Perspective highlights recent developments in methane conversion into different hydrocarbons and oxygenates (methanol, its derivatives, and formaldehyde) with the purpose to address the global demand for efficient and environmentally friendly production of these bulk chemicals. Our analysis identified possible directions for further research to bring the above approaches to a commercial level. As no progress in the development of catalysts for the oxidative coupling of methane could be identified, improvements are expected through reactor operation, cost- and energy-efficient methods for product separation and for providing pure oxygen. With respect to methane oxidation to methanol, further progress can also be achieved by proper catalyst design on the basis of fundamental knowledge especially gained from homogeneous and enzymatic catalysts as well as from theoretical calculations.