Qiangsheng Guo

Highly Efficient Synthesis of C 2 + Oxygenates from CO Hydrogenation Over Rh–Mn–Li/SiO 2 Catalyst: The Effect of TiO 2 Promoter

AbstractThe effect of titanium promotion on the catalytic performance of Rh–Mn–Li catalyst supported on PVP-modified SiO2 for C2+ oxygenates synthesis from CO hydrogenation was investigated. The highest selectivity toward C2+ oxygenates (51.3%) was achieved over the RML/0.5Ti/SiO2 catalyst. Characterization results indicates that the addition of Ti promotes the adsorption of geminal CO and the formation of Rh+, which is favorable for the CO insertion into metal-CHx band, and finally increases the selectivity of C2+ oxygenates.Graphical AbstractThe effect of titanium promotion on the catalytic performance of Rh–Mn–Li catalyst supported on PVP-modified SiO2 for C2+ oxygenates synthesis from CO hydrogenation was investigated. The highest selectivity toward C2+ oxygenates (51.3%) was achieved over the RML/0.5Ti/SiO2 catalyst

The effects of PVP-modified SiO2 on the catalytic performance of CO hydrogenation over Rh–Mn–Li/SiO2 catalysts

Rh–Mn–Li catalysts supported on SiO2 prepared by PVP-modified Stober method were used for the synthesis of C2+ oxygenates from CO hydrogenation. The catalysts were characterized by TG, XRD, N2-adsorption–desorption, TEM, H2-TPR, in situ FT-IR, TPSR, and XPS. Activity testing results showed that the Rh–Mn–Li catalyst supported on the SiO2 modified by 1 g PVP exhibited the highest CO conversion and selectivity of C2+ oxygenates compared with other catalysts. Characterization results indicated that the addition of an appropriate amount of PVP is beneficial to the formation of weakly H-bonded hydroxyl groups on the surface of SiO2, which promotes Rh dispersion and weakens the Rh–Mn interaction. Furthermore, the higher Rh dispersion and the weaker Rh–Mn interaction promote CO absorption, enhance the CO dissociation ability and restrain the hydrogenation activity, which are favorable for the CO insertion into the metal–CHX band, finally resulting in excellent catalytic performance for C2+ oxygenates synthesis.

Photothermal catalytic activity of combustion synthesized LaCoxFe1−xO3 (0 ≤ x ≤ 1) perovskite for CO2 reduction with H2O to CH4 and CH3OH

A range of LaCoxFe1−xO3 perovskites with different Co-doping at the B-site were successfully synthesized via a sol–gel combustion route. Phase pure samples were obtained by calcination at 700 °C for 2 h. The morphology, crystal structure, surface area, band structures, oxygen vacancies and catalytic properties of each analog were characterized in detail. The band structures and oxygen vacancies of the catalysts were changed by adjusting the dopant concentration. The catalytic performance of the LaCoxFe1−xO3 materials was characterized using water as a hydrogen source in the production of CH4 and CH3OH from CO2. Under photothermal conditions, 350 °C with a visible light source equipped with 420 nm cut filter, it was found that x value will influence the total yield and the solar to CH4 and CH3OH energy conversion efficiency significantly. For x = 0.6 compound, the production of CH4 and CH3OH evolution can reach 437.28 and 13.75 μmol g−1 in 6 h, which were 3.2 and 4.0 times that of LaFeO3 under the same condition. The overall solar-to-methane efficiency and solar-to-methanol efficiency for LaCo0.6Fe0.4O3 were 0.603%, 0.019% and for LaFeO3 were 0.191%, 0.005% in the photothermal mode, respectively. The results show that the band gap energy is correlated with the photothermal activity and the LaCo0.6Fe0.4O3 has the position of the CB and VB more suitable for CO2 reduction. The CB and VB value of LaCo0.6Fe0.4O3 were −0.258 and +1.422 V and CO2 (−0.24 V for CB) can be reduced to methane under the conditions.