Dual‐function catalysis in propane dehydrogenation over Pt₁–Ga₂O₃ catalyst: Insights from a microkinetic analysis

Abstract

The kinetics of propane dehydrogenation over single‐Pt‐atom‐doped Ga2O3 catalyst has been examined by combining density functional theory calculations and microkinetic analysis. The doping of Pt not only can improve the selectivity of the Ga2O3 catalyst by hindering the deep dehydrogenation reactions but also helps to achieve a long‐term stability by improving the resistance of Ga2O3 to hydrogen reduction. Microkinetic analysis indicates that upon Pt doping the turnover frequency for propane consumption is increased by a factor of 2.8 under typical operating conditions, as compared to the data on the pristine Ga2O3 surface. The calculated results suggest that the Pt1–Ga2O3 catalyst shows a bifunctional character in this reaction where the Pt–O site brings about dehydrogenation while the Ga–O site is active for desorbing H2, which provides a beautiful explanation for the previous experimental observation that even trace amounts of Pt can dramatically improve the catalytic performance of Ga2O3.

Rational screening of single-atom-doped ZnO catalysts for propane dehydrogenation from microkinetic analysis

“…One can see from the figure that among Pd1-ZnO, Mn1-ZnO, Cu1-ZnO, and Pt1-ZnO, the two noble-metal-doped catalysts prefer to activate the H-H and H-O bonds at the Zn-O site and, consequently, the structural stability remains unsatisfactory owing to the ready formation of oxygen vacancies. By contrast, Mn1-ZnO and Cu1-ZnO favor H2 desorption at the M-O site, which is different from the theoretical predications by Chang et al 62 who claimed that the Pt1-Ga2O3 catalyst shows a bifunctional character in PDH where the Pt-O site brings about dehydrogenation while the Ga-O site is active for desorbing H2. More importantly, Mn1-ZnO is the sole catalyst that has a lower energy barrier for hydrogen recombination than for H2O formation occurring at either the Zn-O or the M-O site and Cu1-ZnO has the two activation energies comparable, both of which showing even better stability than Pt1-ZnO in the reducing atmosphere.…”

“…Please do not adjust margins The formation energies of the species are calculated in the same way as that suggested in earlier studies. 61,62 the overall rate on the ZnO-based catalysts is generally controlled by a TOF-determining transition state that is for either the first or the second dehydrogenation step. Exceptions occur on Fe1-ZnO and ZnO where the kinetics is governed by a TOF-determining intermediate, namely, the individually adsorbed 2-propyl and H, as has been demonstrated in a previous microkinetic analysis study.…”

“…Fig. 7 Calculated formation energies of (a) propylene, (b) 2-propyl&H, and (c) H&H as a function of the formation energies of adsorbed H at the O site and adsorbed 2-propyl at the M site.The formation energies of the species are calculated in the same way as that suggested in earlier studies 61,62. …”

Propylene Synthesis: Recent Advances in the Use of Pt-Based Catalysts for Propane Dehydrogenation Reaction

“…Combining microkinetic analysis and DFT calculations, a Pt-doped Ga 2 O 3 catalytic system was studied, and its bifunctional character was demonstrated [31]. At the Ga(o)-O site, a Lewis acid-base interaction occurs when a pair of H atoms can be coadsorbed at the Ga(o) and O ion pair, thus providing a positive effect on hydrogen recombination.…”

Surface phase transformation of ZrO2 in VOx/ZrO2 catalysts for boosting propane nonoxidative dehydrogenation

“…The propane nonoxidative dehydrogenation (PDH) technology is a practical, value‐added, and environmentally protected pathway compared with traditional cracking technology 5 . Nowadays, the design and fabrication of highly efficient catalysts with environmental friendliness and low cost are crucial for developing PDH technology 6,7 . A series of prospective PDH catalysts have been researched, such as transition metals, noble metals, nontransition metals, and so on 8–10 .…”