Oxygen vacancies generated by Sn-doped ZrO2 promoting the synthesis of dimethyl carbonate from methanol and CO2

Oxygen vacancy sites on a catalyst surface have been extensively studied and been proved to promote the adsorption and activation of carbon dioxide. We use Sn-doped ZrO₂ to prepare a Zr/Sn catalyst rich in oxygen vacancies (OVs) by co-precipitation. The yield of dimethyl carbonate is 5 times that of ZrO₂. Compared with the original ZrO₂, Zr/Sn exhibits a higher specific surface area, number of acid–base sites and a lower band gap, which improves the conductivity of electrons and creates more surface. The number of reaction sites greatly enhances the adsorption and activation capacity of CO₂ molecules on the catalyst surface. In situ infrared spectroscopy shows that CO₂ adsorbs on oxygen vacancies to form monomethyl carbonate, and participates in the reaction as an intermediate species. This work provides new clues for the preparation of ZrO₂-based catalysts rich in oxygen vacancies to directly catalyze the synthesis of dimethyl carbonate from methanol and CO₂.

Oxygen vacancy sites on a catalyst surface have been extensively studied and been proved to promote the adsorption and activation of carbon dioxide.

Formation, dynamics, and long-term stability of Mn- and Fe-promoted Rh/SiO2 catalysts in CO hydrogenation

Fe servers as an electronic modifier on Rh/SiO2 through in situ RhFe nanoalloy formation, whereas Mn is more likely a structural modifier and does not substantially change Rh's intrinsic product spectrum.

Hydroxyl-mediated ethanol selectivity of CO2 hydrogenation

Oxide-supported Rh nanoparticles have been widely used for CO2 hydrogenation, especially for ethanol synthesis. However, this reaction operates under high pressure, up to 8 MPa, and suffers from low CO2 conversion and alcohol selectivity. This paper describes the crucial role of hydroxyl groups bound on Rh-based catalysts supported on TiO2 nanorods (NRs). The RhFeLi/TiO2 NR catalyst shows superior reactivity (≈15% conversion) and ethanol selectivity (32%) for CO2 hydrogenation. The promoting effect can be attributed to the synergism of high Rh dispersion and high-density hydroxyl groups on TiO2 NRs. Hydroxyls are proven to stabilize formate species and protonate methanol, which is easily dissociated into *CH x , and then CO obtained from the reverse water-gas shift reaction (RWGS) is inserted into *CH x to form CH3CO*, followed by CH3CO* hydrogenation to ethanol.

The effects of the nature of TiO2 supports on the catalytic performance of Rh–Mn/TiO2 catalysts in the synthesis of C2 oxygenates from syngas

Four types of TiO₂ with different rutile/anatase crystalline phase compositions were used as supports, and the effect of the TiO₂ phase composition on the catalytic properties of supported Rh catalysts in the synthesis of C₂ oxygenates from syngas was studied.

Incorporation of reduced graphene oxide into faceted flower-like {001} TiO2 for enhanced photocatalytic activity

Anatase TiO₂ with {001} facets is much more active than that with {101} facets, which has been verified via experiments and theoretical calculations. Graphene has garnered much attention since it was initially synthesized, due to its unique properties. In this study, reduced graphene oxide (RGO)/{001} faceted TiO₂ composites were fabricated via a solvothermal method. The composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrophotometry, photoluminescence and Raman analysis. The results revealed that the graphene oxide was reduced during the preparation process of the {001} faceted TiO₂, and combined with the surface of {001} TiO₂. The photocatalytic activities of the composites were evaluated through the degradation of basic violet, under both white light (λ > 390 nm) and visible light (λ = 420 nm) irradiation. The results indicated that the photocatalytic activities of the {001} faceted TiO₂ were significantly improved following the incorporation of RGO, particularly under visible light irradiation. Theoretical calculations showed that the band structure of the {001} faceted TiO₂ was modified via graphene hybridization, where the separation of photoinduced electron-hole pairs was promoted; thus, the photocatalytic activity was enhanced.

Synthesis of higher alcohols by CO hydrogenation on a K-promoted Ni–Mo catalyst derived from Ni–Mo phyllosilicate

A K_0.5-(Ni₁Mo_0.25)Si-PS catalyst derived from Ni–Mo phyllosilicate exhibits excellent catalytic performance and stability for the synthesis of HAs by CO hydrogenation relative to the catalysts prepared by conventional co-deposition and wetness impregnation methods.

Designing a novel dual bed reactor to realize efficient ethanol synthesis from dimethyl ether and syngas

A novel dual bed reactor packed with H-ferrierite and CuZnAl catalysts for efficient ethanol synthesis from DME and syngas.

Formation of C2oxygenates and ethanol from syngas on an Fe-decorated Cu-based catalyst: insight into the role of Fe as a promoter

Fe-decorated Cu bimetallic catalyst exhibits a high selectivity to ethanol.