CO2 hydrogenation on Pt, Pt/SiO2 and Pt/TiO2: Importance of synergy between Pt and oxide support

Abstract

In the current study we combined density functional theory (DFT), kinetic Monte Carlo (KMC) simulations and experimental measurements to gain insight into the mechanisms of CO 2 conversion by hydrogen on the Pt nanoparticle (NP). The results show that in spite of the presence of active, low-coordinated sites, Pt NP alone is not able to catalyze the reaction due to the weak CO 2 binding on the catalyst. Once CO 2 is stabilized, the hydrogenation of CO 2 to CO via the reverse-water-gas shift (RWGS) reaction is promoted; in contrast, the enhancement for further *CO hydrogenation to CH 4 is less significant and no CH 3 OH is observed. The selectivity to CO is mainly determined by CO binding energy and the energetics of *CO hydrogenation to *HCO, while that for CH 4 and CH 3 OH is determined by the competition between hydrogenation and C-O bond scission reactions of the *H 2 COH species. Using SiO 2 and TiO 2 as the support, Pt NP is able to promote the overall CO 2 conversion, while the impact on the selectivity is rather small. The theoretically predicted trend in activity and selectivity is in good agreement with the experimental results. The enhanced activity of Pt/oxide over Pt is originated from the sites at the Pt-oxide interface, where the synergy between Pt and oxide plays an important role.

Recent Developments in the Modelling of Heterogeneous Catalysts for CO2 Conversion to Chemicals

“…Besides, CuÀ CeO 2 , FeÀ CeO 2 , and MnÀ CeO 2 catalysts maintained 100 % CO selectivity at the temperature 400°C. Pt was investigated in combination with TiO 2 or SiO 2 as a support by different researchers [90,91] where the supports promoted the overall CO 2 conversion, although the impact on the selectivity was rather small. To improve the Pt/TiO 2 catalytic impact on RWGS reaction Lee et al [92] investigated the effect of CeO 2 addition to a Pt/TiO 2 at temperature range 300-600°C.…”

Carbon‐Modified CuO/ZnO Catalyst with High Oxygen Vacancy for CO2 Hydrogenation to Methanol

“…On the Pt/SiO 2 interface, it is difficult to form oxygen vacancy, and CO 2 adsorption is weak. On the contrary, TiO 2 is a reducible carrier, on which oxygen vacancy can adsorb CO 2 strongly . It is reported that there are more oxygen vacancies in the (002) polar plane of ZnO, and there is a stronger interaction between Cu and ZnO with more (002) polar planes .…”

Hydrogenation of Carbon Dioxide to Value-Added Chemicals by Heterogeneous Catalysis and Plasma Catalysis

“…They The support plays an important role in CO 2 hydrogenation to CO through the RWGS reaction. Kattel et al prepared Pt, Pt/SiO 2 and Pt/TiO 2 materials as catalysts for the RWGS reaction [21], and showed that Pt nanoparticles alone cannot catalyze the RWGS reaction, while using SiO 2 and TiO 2 as support, the overall CO 2 conversion can be significantly improved, pointing towards a synergy effect between Pt and the oxide support. To reveal the synergy effect, they combined density functional theory (DFT), kinetic Monte Carlo (KMC) simulations and other experimental measurements.…”