The Promoting Effect of Fe Doping on Rh/CeO2 for the Ethanol Synthesis

Liu, Weigang; Wang, Sheng; Sun, Tianjun; Wang, Shudong

doi:10.1007/s10562-015-1577-5

Cited by 28 publications

(22 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cobalt in the catalyst surface is more favorable for hydrogenation; therefore, as shown in Figure d, with decreasing cobalt content, the CO dissociation decreases. As higher alcohol selectivity is achieved by a moderate hydrogenation ability, better alcohol selectivity is observed with the caesium‐modified 5Co–15Cu catalyst. The addition of caesium enhances the amount of chemisorbed CO on the surface of the catalyst and hence, the ability of CO dissociation increases in the presence of caesium.…”

Section: Resultsmentioning

confidence: 97%

Role of Caesium in Higher Alcohol Synthesis over Modified Copper–Cobalt Nanocomposites under Mild Conditions

2017

View full text Add to dashboard Cite

Cu–Co nanocomposites with and without Cs promoter on a modified lanthanum–alumina support were prepared by the combination of two unique synthesis methods. The synthesized materials were exclusively characterized by means of XRD, BET surface area determination, H2 temperature‐programmed reduction, CO2 temperature‐programmed desorption, N2O frontal chromatography, X‐ray photoelectron spectroscopy, high‐resolution TEM, and elemental mapping techniques, and its catalytic properties were thoroughly investigated for the selective synthesis of higher alcohols in the CO hydrogenation reaction by using a H2/CO ratio of 1, a temperature range of 180–300 °C and a pressure variation of 15–60 bar. Cs incorporation and a Cu/Co ratio of three was found to be a very efficient combination to obtain alcohol selectivities up to 55 %. This was explained by the fact that Cs increases the surface area of Cu particles by migrating Cu towards the surface layer and strengthens the surface interaction of Cu and Co. The further increase in higher alcohols selectivity then results from the limited formation of methane and carbon dioxide.

show abstract

Section: Resultsmentioning

confidence: 97%

Role of Caesium in Higher Alcohol Synthesis over Modified Copper–Cobalt Nanocomposites under Mild Conditions

2017

View full text Add to dashboard Cite

show abstract

“…Previous work suggests that Rh-Fe 3+ -O species are active sites for the generation of C 2 oxygenates such as ethanol [5,9]. Considering the contribution of Rh 0 and Rh + to CO insertion ability, the active site for ethanol formation over Rh-Fe/ Al 2 O 3 catalyst was assumed to the (Rh x 0− Rh y + ) -O-Fe 3+ (Fe 2+ ) sites with reference to that of Rh-Mn catalysts [18]. These active sites could be formed by the close contact between Rh and Fe.…”

Section: Catalytic Performance Of Catalystsmentioning

confidence: 99%

“…Mo et al [17] found Fe decreased CO adsorption but improved hydrogenation ability of Rh-based catalysts. Liu et al [18] found that the doping of Fe changed CO dissociation behavior over Rh/CeO 2 catalyst during the experiments of CO adsorption and CO temperature programmed surface reaction (TPSR). Therefore, DRIFTS technique would be a very useful tool to understand the promotion of promoter from the view of elementary steps of ethanol formation, and to explain the difference in catalytic activity from a different view.…”

Section: Introductionmentioning

confidence: 99%

DRIFTS study of Fe promoter effect on Rh/Al2O3 catalyst for C2 oxygenates synthesis from syngas

Qian

2019

Appl Petrochem Res

View full text Add to dashboard Cite

DRIFTS experiments such as CO adsorption, CO-TPSR and CO+H 2 were designated to study the effect of Fe promoter on the key steps of C 2 oxygenates formation from syngas. The CO adsorption results demonstrated that Fe weakened CO adsorption and especially the bridging adsorption. It was found in CO-TPSR experiments that the catalyst with lower Fe loading is more easily dissociated while the ones with higher Fe loading own stronger hydrogenation activity. Moreover, it was observed by CO+H 2 experiments that Fe plays a role in stabilizing the lineally adsorbed CO species and decreasing the CO desorption rate. The catalytic performance results indicated that when Fe content is 4wt. %, the selectivity of total C 2 oxygenates is the highest, which was in accordance with the DRIFTS results.

show abstract

“…Much less work was conducted for CO adsorption on Rh/CeO 2 at a low temperature because the bulk of the work, mostly by IR, was conducted for the purpose of water gas shift reaction (WGSR), syngas conversion, ethanol synthesis from syn gas, and CO oxidation among other reactions [17][18][19][20]. The Rh/CeO 2 catalysts themselves have been well studied for decades where metallic Rh particles are formed upon reduction, although the as prepared Rh/CeO 2 contains Rh particles with several oxidation states and possibilities of Rh ions substitution of Ce cations [21,22].…”

Section: Introductionmentioning

confidence: 99%

Low Temperature Infrared Study of Carbon Monoxide Adsorption on Rh/CeO2

Idriss

Llorca²

2019

Catalysts

View full text Add to dashboard Cite

Fundamental studies of the interaction of adsorbates with metal oxides alone and on which a noble metal is deposited provide information needed for catalytic reactions. Rh/CeO2 is one of the textbook catalysts for many reactions including syngas conversion to ethanol, water gas shift reaction (WGSR), and ethanol steam reforming. In this work, the adsorption of CO is studied by infrared (IR) spectroscopy, over CeO2 and 0.6 at. % Rh/CeO2 at a temperature range of 90 to 300 K. CeO2 is in the form of nanoparticles with sizes between 5 and 10 nm and exposing predominantly {111} surface termination in addition to non-negligible fraction of the {100} termination, determined from high resolution transmission electron microscopy (HRTEM). The as prepared Rh/CeO2 contained metallic Rh as well Rh cations in higher oxidation states. At 90 K two IR bands were observed at 2183–2186 and 2161–2163 cm−1, with the former saturating first. The 2163 cm−1 peak was more sensitive to CO pressure than the 2186 cm−1. Heating resulted in the depopulation of the 2163 cm−1 before the 2186 cm−1 peak. The desorption energy computed, assuming a first-order desorption kinetic, was found to be 0.35 eV for the 2186 cm−1 and 0.30 for the 2163 cm−1 IR peak (+/−0.05 eV). The equilibrium constant at 90 K was computed equal to 1.83 and 1.33 Torr−1 for the 2183 and 2161 cm−1, respectively. CO adsorption at 90 K on Rh/CeO2 resulted (in addition to the bands on CeO2) in the appearance of a broad band in the 2110–2130 cm-1 region that contained two components at 2116 and 2126 cm−1. The high frequency of this species is most likely due to adsorption on Rh clusters with very small sizes. The desorption energy of this species was found to be equal to 0.55 eV (+/−0.05 eV). Heating the CO covered Rh/CeO2 surface accelerated the disappearance of CO species over CeO2 and resulted in the appearance of CO2 bands (at about 150 K) followed by carbonate species. At 300 K, the surface was mainly composed of carbonates.

show abstract

The Promoting Effect of Fe Doping on Rh/CeO2 for the Ethanol Synthesis

Cited by 28 publications

References 54 publications

Role of Caesium in Higher Alcohol Synthesis over Modified Copper–Cobalt Nanocomposites under Mild Conditions

Role of Caesium in Higher Alcohol Synthesis over Modified Copper–Cobalt Nanocomposites under Mild Conditions

DRIFTS study of Fe promoter effect on Rh/Al2O3 catalyst for C2 oxygenates synthesis from syngas

Low Temperature Infrared Study of Carbon Monoxide Adsorption on Rh/CeO2

Contact Info

Product

Resources

About