Initial steps in methanol steam reforming on PdZn and ZnO surfaces: Density functional theory studies

Smith, Gregory; Lin, Sen; Lai, Wenzhen; Datye, Abhaya K.; Xie, Daiqian; Guo, Hua

doi:10.1016/j.susc.2011.01.014

Cited by 63 publications

(83 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, Karim et al investigated the effect of ZnO morphology on the reactivity of PdZnO catalysts for MSR [7], and concluded that the activity was higher for faceted ZnO materials [7]. In line with the former work, the theoretical studies by Smith et al demonstrated that the polar crystalline surfaces of ZnO has null energetic barrier for both methanol and water dissociation [8]. On this basis, one could assume that ZnO with higher ratio of polar surfaces, namely higher polarity ratio, would lead to MSR catalysts with enhanced activity.…”

Section: Introductionmentioning

confidence: 85%

“…Equations characterizing the reactor performance: 8 where QCO,out, QCO 2 ,out and QTOT,out are the CO, CO2 and total outlet molar flow rates, respectively, QH 2 , retentate and QH 2 ,permeate are the H2 outlet molar flow rates of retentate and permeate sides; and QTOT, retentate and QTOT,permeate are the total outlet molar flow rates of retentate and permeate sides; Q CH 3 OH, in is the inlet stream of methanol fed to the MR and Q i,out is the outlet molar flow rate of "i"-component (CO, CO2, H2).…”

Section: Msr With a Composite Pd-al2o3membrane Reactormentioning

confidence: 99%

See 1 more Smart Citation

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

Mateos-Pedrero

Silva

Tanaka

et al. 2015

Applied Catalysis B: Environmental

119

View full text Add to dashboard Cite

The effect of surface area and polarity ratio of ZnO support on the catalytic properties of CuO/ZnO catalyst for methanol steam reforming (MSR) are studied. The surface area of ZnO was varied changing the calcination temperature, and its polarity ratio was modified using different Zn precursors, zinc acetate and zinc nitrate. It was found that the copper dispersion and copper surface area increase with the surface area of the ZnO support, and the polarity ratio of ZnO strongly influences the reducibility of copper species. A higher polarity ratio promotes the reducibility, which is attributed to a strong interaction between copper and the more polar ZnO support. Interestingly, it was observed that the selectivity of CuO/ZnO catalysts (lower CO yield) increases with the polarity ratio of ZnO carriers. As another key result, CuO/ZnOAc375 catalyst has proven to be more selective (up to 90%) than a reference CuO/ZnO/Al2O3 sample (G66-MR, Süd Chemie).The activity of the best performing catalyst, CuO/ZnOAc-375, was assessed in a Pd-composite membrane reactor and in a conventional packed-bed reactor. A hydrogen recovery of ca. 75% and a hydrogen permeate purity of more than 90% was obtained. The Pd-based membrane reactor allowed to improve the methanol conversion, by partially suppressing the methanol steam reforming backward reaction, besides upgrading the reformate hydrogen purity for use in HT-PEMFC.2

show abstract

Section: Introductionmentioning

confidence: 85%

Section: Msr With a Composite Pd-al2o3membrane Reactormentioning

confidence: 99%

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

Mateos-Pedrero

Silva

Tanaka

et al. 2015

Applied Catalysis B: Environmental

119

View full text Add to dashboard Cite

show abstract

“…14,15 The basal polar planes of ZnO were reported to be much more active in photocatalysis as compared to the nonpolar facets, due to a higher density of defects such as oxygen vacancies. 16 Plane-density functional theory calculations performed by Guo et al also indicate the contribution of polar facets for a low-temperature pathway reaction of methanol steam reforming; 17 according to their calculations the dissociation of both water and methanol have low or null barriers on the polar Zn-ZnO(0001). The effect of different nanoshapes of ZnO in methanol steam reforming and water gas-shi reactions was studied by Flytzani-Stephanopoulos et al and the activity was higher with the increasing number of polar facets exposed.…”

Section: 13mentioning

confidence: 99%

Simple hydrothermal synthesis method for tailoring the physicochemical properties of ZnO: morphology, surface area and polarity

et al. 2014

View full text Add to dashboard Cite

A simple urea-assisted hydrothermal synthesis method was used to tailor the physicochemical properties of ZnO materials. The role of Pluronic P123 block copolymer in the crystal growth, morphology and specific surface area of the as-prepared ZnO was studied. When Pluronic P123 is used, well-dispersed hierarchical microspheres, with a flower-like morphology, are obtained, but in its absence large spherical agglomerated clusters are formed. The polarity of the ZnO, measured as the ratio between plane (002) and plane (100), is also significantly higher for the Pluronic P123 sample. The influence of zinc salt precursors was also analysed. The use of zinc nitrate led to the formation of urchin-like ZnO structures, instead of the microflowers that result from zinc acetate salt. Despite having similar surface areas, the polarity of the zinc nitrate sample was much smaller. The decomposition of methylene blue corroborated the higher photocatalytic activity of the ZnO materials with a higher proportion of polar planes (higher polarity). The formation mechanism of the crystals is also suggested based on the observed gradual growth and assembly of the hydrozincite during the initial steps of the synthesis for the samples with and without Pluronic P123.

show abstract

“…At high-temperatures methanol can decompose and side reactions can appear [3,22,23]. The important role of the formaldehyde intermediate has been demonstrated by the observation [7] that if steam reforming starts with formaldehyde (formaldehyde steam reforming, FSR) the reaction products remain essentially the same as for MSR.…”

Section: Introductionmentioning

confidence: 99%

“…From the observation that supported and unsupported catalysts show comparable selectivities [30,31] one could conclude that the role of the ZnO support on the selectivity is not significant. However, recent studies demonstrated [23,26] that the ZnO support and perhaps also oxidized surface Zn can play an important role in the activity and selectivity of the PdZn catalyst. The ZnO support itself has been identified [26] as an almost 100% CO 2 selective catalyst for both MSR and FSR.…”

Section: Introductionmentioning

confidence: 99%

Understanding the selectivity of methanol steam reforming on the (1 1 1) surfaces of NiZn, PdZn and PtZn: Insights from DFT

Krajčı́

Tsai

Häfner

2015

Journal of Catalysis

View full text Add to dashboard Cite

Initial steps in methanol steam reforming on PdZn and ZnO surfaces: Density functional theory studies

Cited by 63 publications

References 64 publications

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

Simple hydrothermal synthesis method for tailoring the physicochemical properties of ZnO: morphology, surface area and polarity

Understanding the selectivity of methanol steam reforming on the (1 1 1) surfaces of NiZn, PdZn and PtZn: Insights from DFT

Contact Info

Product

Resources

About