A well fabricated PtSn/SiO₂ catalyst with enhanced synergy between Pt and Sn for acetic acid hydrogenation to ethanol

Abstract

This work reported a well-fabricated PtSn/SiO 2 catalyst prepared by a modified two-step sol-gel (MTSG) method. The adoption of strong electrostatic adsorption (SEA) and sol-gel (SG) method could give both a significantly high Pt dispersion and a large amount of Lewis acid sites. The homogenous distribution of Sn species could not only provide more opportunity for the Pt precursor to disperse on the support by forming Pt-(O-Sn^) y 2Ày analogous species, but also enhance the synergy between Pt and Sn species.Consequently, an excellent activity was achieved in the hydrogenation of acetic acid (AcOH) with a conversion of 100% and ethanol (EtOH) selectivity of 93%. Investigations on the effect of Sn/Pt molar ratio showed that the dispersion of Pt decreases obviously with the increasing Sn/Pt ratio due to the geometric or electronic effects caused by SnO x species. A balancing effect between Pt active sites and Lewis acid sites was found to be responsible for the superior catalytic performance in AcOH hydrogenation. Moreover, a parallel reaction path model was proposed for the hydrogenation of AcOH over PtSn/SiO 2 catalyst, in which ethanol and ethyl acetate (AcOEt) are formed competitively through the adsorbed ethoxy intermediate. † Electronic supplementary information (ESI) available: Fig. S1 shows the N 2 adsorption-desorption isotherms and pore size distribution of reduced catalysts. Fig. S2 displays the HAADF-STEM and EDX elemental-mapping images of the reduced PtSn1.6/SiO 2 -MTSG catalyst. Fig. S3 shows the TEM images of reduced PtSnx/SiO 2 -MTSG catalysts. Fig. S4 represents the deconvolution of the t about FTIR spectra of chemisorbed pyridine on reduced catalysts. Fig. S5 displays the hydrogenation performance of AcOH over PtSn1.6/SiO 2 -MTSG catalyst as a function of WHSV (AcOH) . Table S1 shows the tted results of H 2 -TPR experiments of catalysts. Table S2 displays the integral quantity of Lewis acid sites of reduced catalysts. Table S3 illustrates the hydrogenation performance of AcOH over PtSn1.6/SiO 2 -MTSG catalysts. See

Recent Developments of Heterogeneous Catalysts for Hydrogenation of Carboxylic Acids to their Corresponding Alcohols

“…The active species of the catalyst seems to be Pt‐Sn alloy, which is also similar to that suggested by the previous work of Dumesic and co‐workers, however, the role of CNT was unclear. On the other hand, Zhang and Zhao and co‐workers reported that two‐step sol‐gel preparation method was effective for the synthesis of Pt‐Sn/SiO 2 catalyst, showing high activity and selectivity at the Sn/Pt molar ratio of 1.6 (Table , entry 9) . The authors suggested that both Pt metal and Sn Lewis acid sites are responsible for high catalytic performance.…”

“…On the other hand, Zhang and Zhao and co-workers reported that two-step sol-gel preparation method was effective for the synthesis of Pt-Sn/ SiO 2 catalyst, showing high activity and selectivity at the Sn/Pt molar ratio of 1.6 (Table 3, entry 9). [70] The authors suggested that both Pt metal and Sn Lewis acid sites are responsible for high catalytic performance. The high stability of Pt-Sn bimetallic catalysts was confirmed in both the cases.…”

Catalytic Platinum Nanoparticles Decorated with Subnanometer Molybdenum Clusters for Biomass Processing

“…Addition of a second metal can usually improve either catalytic activity or selectivity. Addition of Sn to Pt, for example, improves selectivity but reduces activity …”

Effect of Sn_xPt_y Alloy Structures in SnPt Bimetallic Nanoparticle Catalysts on Catalytic Activity for Hydrogenation of Acetic Acid

“…Meanwhile, Hara and Endou (2003) and Taniguchi et al (2011) independently reported that the addition of Pt to the supported Ru-Sn improved the catalytic activity for the hydrogenation of 1,4-cyclohexanedicarboxylic acid to 1,4-cyclohexane dimethanol and that of methyl laurate to lauryl alcohol, respectively. e supported SnPt bimetallic catalysts were reported to be e ective for the gas-phase hydrogenation of acetic acid to ethanol (Zhang et al, 2014(Zhang et al, , 2015Xu et al, 2016aXu et al, , 2016b.…”

“…However, no monometallic or bimetallic phase was observed in these Sn-promoted bimetallic catalysts with high catalytic activity. is is because of the high dispersion of the metal species on the catalysts (Zhang et al, 2014(Zhang et al, , 2015Xu et al, 2016aXu et al, , 2016b, which makes it di cult to clarify the actual e ective sites for the hydrogenation of carboxylic acids. In our previous work using SnPt bimetallic nanoparticles fabricated by a polyalcohol reduction process, varying the Sn x Pt y alloy structures played an important role in controlling the catalytic activity and selectivity for the chemoselective hydrogenation of crotonaldehyde to crotyl alcohol: the Sn 1 Pt 3 alloy phase indicated the highest catalytic activity, while the maximum selectivity toward crotyl alcohol as the target product was achieved over the Sn 1 Pt 1 alloy structure (Taniya et al, 2018).…”