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[Display omitted] • Co/ZrO 2 catalysts with single Co2+ are efficient for C 3 H 8 dehydrogenation to C 3 H 6. • 1Co/ZrO 2 performed durable over multiple dehydrogenation/regeneration cycles. • 1Co/ZrO 2 showed higher activity than a commercial analogue of K-CrO x /Al 2 O 3. • The high activity results from a synergy effect between Co2+ and Zr cus. • Recombination of surface H species is the rate-limiting step in C 3 H 6 formation. Due to the increased production of shale gas containing propane, the share of non-oxidative propane dehydrogenation (PDH) in the large-scale production of propene is expected to continue to grow. There are, however, some ecofriendly and cost shortcomings associated with the currently applied Cr- or Pt-containing catalysts. Against this background, we present here Co/ZrO 2 alternatives and reveal the fundamentals affecting their activity, which can be used for purposeful catalyst design. Co2+ species homogeneously distributed within the lattice of ZrO 2 significantly increase the activity of coordinatively unsaturated Zr4+ for the PDH reaction. The increase is caused by accelerating both the cleavage of CH bonds in propane and the recombination of surface H species, with the latter reaction being the rate-limiting step. The best-performing catalyst outperformed an analogue of commercial K-CrO x /Al 2 O 3 in terms of the rate of propene formation and demonstrated durable performance over a series of 10 PDH/regeneration cycles under industrially relevant conditions. It also outperformed most previously developed Co-containing catalysts in terms of propene productivity. The space–time yield of propene formation achieved at 57 % equilibrium propane conversion at 550 °C was 0.71 kg·h−1·kg cat -1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Alkali metal in MnO x -M 2 WO 4 /SiO 2 affects activity under anaerobic conditions. • Lattice oxygen of MnO x -M 2 WO 4 /SiO 2 can convert CH 4 to hydrocarbons. • OCM over MnO x -M 2 WO 4 /SiO 2 and M 2 WO 4 /SiO 2 proceeds via adsorbed oxygen species. • Presence of MnO x does not create more active sites but changes their reactivity. This work unveils the fundamentals relevant for activity and product selectivity in the oxidative coupling of methane (OCM) over the (MnO x)-M 2 WO 4 /SiO 2 (M = Na, K, Rb, or Cs) catalysts. The presence of the molten phase of Na 2 WO 4 and the ability of the catalysts to release lattice oxygen were not found to be the performance-governing factors. As proven by oxygen isotopic exchange experiments combined with thorough catalytic tests, the performance of both tri- and bimetallic catalysts is defined by the involvement of adsorbed oxygen species formed from gas-phase O 2. Lattice oxygen of M 2 WO 4 /SiO 2 is not capable of converting CH 4 to C 2 H 6 , while that of MnO x -M 2 WO 4 /SiO 2 is active for this reaction. The OCM activity of M 2 WO 4 /SiO 2 decreases with the atomic weight of alkali metal, whereas there is no such effect in the presence of MnO x , which, however, increases the activity. The enhancing effect was explained by improving the active site turnover. [ABSTRACT FROM AUTHOR]

[Display omitted] • The dependence of the rate of propene formation on Ga/Zr ratio over Ga 2 O 3 /ZrO 2 was determined for PDH. • The reaction intermediates and mechanism were studied by in-situ DRIFTS and DFT calculations. • GaⅡ–O 3c Ⅱ structure was determined as the active site with enhanced C–H bond activation ability over Ga 2 O 3 /ZrO 2. • Ga 2 O 3 /ZrO 2 catalyst showed a good reaction-regeneration stability. ZrO 2 -based catalysts have attracted extensive attention in propane dehydrogenation (PDH) owing to their environmental compatibility, low costs, and superior catalytic performance. However, the structure–activity relationship and mechanistic analysis of Ga 2 O 3 /ZrO 2 in PDH are rarely studied where GaO x either acts as an active site or a promoter. Here, Ga 2 O 3 /ZrO 2 catalysts with different Ga/Zr ratios were synthesized by the impregnation technique, and the structure–activity relationship was revealed by combining complementary in/ex-situ characterization methods with catalytic tests. It is found the rate of propene formation first increases linearly and then reaches a plateau with the increase of Ga 2 O 3 loading, such activity-loading dependence is related to the evolution of Ga 2 O 3 species varying from monodisperse to single-layer and then multilayer states. Activation energy and C 3 H 8 -TPSR results suggest the formation of a new active site with high intrinsic activity over Ga 2 O 3 /ZrO 2. Furthermore, the molecular level reaction mechanism of Ga 2 O 3 /ZrO 2 in PDH was studied by DFT calculations, which pointed out the active site structure was GaⅡ–O 3c Ⅱ site exhibiting enhanced activation ability toward C–H bond and lower reaction barrier compared with bare ZrO 2. This work is expected to offer new insights into understanding the structure–activity relationships over ZrO 2 -based catalysts for PDH reaction. [ABSTRACT FROM AUTHOR]