Jie Sun,Shaolong Wan,Fen Wang,Jingdong Lin,Yong Wang
A variety of catalysts for higher alcohol synthesis from syngas have been under development for potential commercial application, which are still facing challenges, including poor carbon efficiency due to low selectivity to desired products. In this contribution, we systematically studied the effects of temperature, loading of K and Cs, space velocity, and CO2 addition on the alkali-promoted Cu/ZnO/Al2O3 catalysts in order to achieve a high yield of desired higher alcohol products. Our particular focus was to maximize the carbon efficiency by restricting the amount of undesired byproducts, such as lower alkanes and CO2 that could be formed. Among K and Cs promoted Cu/ZnO/Al2O3 catalysts studied, Cs-promoted Cu/ZnO/Al2O3 catalysts exhibit better performance to higher alcohols and higher carbon efficiency than K-promoted counterparts under similar conditions studied. 1.64 mol % Cs-promoted Cu/ZnO/Al2O3 catalyst achieves the highest selectivity to higher alcohols (24.9%) at a CO conversion of 41.6% under 290 °C, 1875 mL g–1cat h–1, 5.4 MPa. The presence of a small amount of CO2 of 2.5 mol % in the feed has negligible effect on the productivity of higher alcohols but significantly suppresses the formation of CO2 byproduct. With the further increase of CO2 in the feed, the formation of CO2 can be further suppressed but at the expense of productivity loss of higher alcohols, which is probably due to the neutralization of surface Cs sites. The best carbon efficiency can be achieved at 8% mol CO2 in the feed.
Ziwei Guo,Feng Zhou,Hao Wang,Xiaohao Liu,Guangyue Xu,Ying Zhang,Yao Fu
A novel and green catalytic system based on a Pd stabilized CuZnAl catalyst was designed for one-pot conversion of natural oil components to the corresponding alcohols or long-chain linear and branched alkanes with high selectivity and atom economy. When methyl decanoate was used as the model compound, a nearly full yield of n-decanol was obtained at 200 °C and 2 MPa H2 within 8 h. 100% decane was produced when acidic HZSM-5 was introduced under the same reaction conditions, and the selectivity of n-decane and i-decane could be tuned by temperature. Cu species were verified as the active sites for lipid conversion, while a small amount of Pd could stabilize the catalyst to avoid Cu leaching. The reaction pathway involved hydrogenation, where methyl decanoate can be equivalently converted to methanol and decanol or decane, and no extra CO2 or CO from decarboxylation or decarbonylation was detected. This system increases the sustainability and economy of natural oil conversion to valuable liquid fuel and chemicals.
Chunchao Chen,Xiang Gao,Boyu Yuan,Chao Wang,Juan Qiu,Kangwei Gongsun,Ke Lu,Houyi Ma
A smart means to achieve the harmless treatment of corrosive Cl – have been proposed for protecting brass. In this method, intelligent self-healing nanofilms based on the interlayer anion exchange properties of LDHs in situ grow on brass surfaces. The Cl – ions replace the BTA – loaded between LDHs interlayers to induce self-healing, as the binding energy of Cl – is lower than that of BTA – , obtained from theoretical calculations. The simultaneous application of electrochemistry and digital holography technologies confirmed that the constructed film has high instantaneous corrosion inhibition efficiency (99.9 %), long-lasting corrosion resistance, and self-healing ability (50 days).
As a greenhouse gas, carbon dioxide is also a rich carbon resource that can be effectively utilized to tackle the global warming crisis. This paper presents an in-depth investigation of the impact of the Cu content on the structure of Cu–Zn–Al layered double hydroxides (LDHs) from a novel perspective. The CO2 hydrogenation performance of the derived catalyst, the LDO, is also evaluated in the methanol synthesis reaction. All catalysts were evaluated at 3.0 MPa, a carbon dioxide to hydrogen ratio of 3, and a space velocity of 3600 mL·g–1·h–1. The results from this work indicate that the catalyst with a Cu:Zn ratio of 11:4 exhibited the highest methanol selectivity of 63.9% at 230 °C. At 250 °C, the catalysts also yielded the highest methanol selectivity of 50% only, along with a CO2 conversion as high as 17.8%. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) data suggest that the CO2-to-methanol reaction follows the formate (HCOO*) mechanism for this catalyst. Results from this work offer a novel approach to designing Cu-LDH-based catalysts, which offers valuable insights for the efficient chemical utilization of CO2.
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