Simulated Temperature Programmed Desorption of Acetaldehyde on CeO2(111): Evidence for the Role of Oxygen Vacancy and Hydrogen Transfer

H2 Dissociation and Oxygen Vacancy Formation on Ce2O3 Surfaces

“…Indeed, a stable termination tends to be more inertand so less reactivethan other less stable surfaces. It can be seen from Table 4 that the (01-11), (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) terminations display similar formation energy values for surface and subsurface sites, indicating a similar stabilization of the O-defective system. However, the (0001) termination shows the opposite behavior, indicating that the local environment of the vacancy in the subsurface position is more stabilizing for the vacancy.…”

“…The DOS of the oxygen vacancy is similar to the bulk one and is given in the Supplementary Information. For the (01-11), (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) terminations which have nonequivalent (sub)surface oxygen sites, all the different oxygen vacancies configuration were investigated and their formation energies were summarized in Table 4. Moreover, the large formation energy of such defect (> 5.5 eV) indicates that the surfaces retain the non-reducible character of the bulk.…”

“…This indicates that Ce 2 O 3 stabilizes the heterolytic product compared to CeO 2 who tends to lead to an unstable (H + ,H -) product. 33,34,38 Furthermore, the activation energy of the dissociation is very low, from 0.04 eV for (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) to 0.13 eV for (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) Table 5. Adsorption energies (in eV) of the species involved in the H 2 dissociation process.…”

“…The former is related to the presence of oxygen vacancies without change of the crystalline structure (typically a fluorite) whereas the latter corresponds to the limit case where all the Ce atoms are reduced into Ce 3+ with a sesquioxide A-type (hexagonal) structure. 10 In the last years, much effort was put in the comprehension of the partial reduction impact on the ceria surface property [11][12][13][14][15][16] and reactivity [17][18][19][20][21] , with much less insight in Ce 2 O 3 compositions. In standard conditions of pressure and temperature, Ce 2 O 3 is not a stable material but recent development of new experimental techniques and protocols make possible the synthesis of Ce 2 O 3 particles.…”

CheKiPEUQ Intro 1: Bayesian Parameter Estimation Considering Uncertainty or Error from both Experiments and Theory**

“…For these three models, CPE and BPE were performed with the same sequence of steps: Step 1) Start with the initial parameters guess, which is also the mean of the prior, and perform one of several grid‐search variations to find the optimum grid‐point. For all three models and each state therein, the initial guess for each activation energy for desorption is 41.5 kJ/mol and for each pre‐exponential is 10 13 s −1 [27,99, 101] . During the Step 1 grid‐search, each grid‐point is either taken directly or a local optimization is performed, as described in the next paragraph.…”