Catalytic oxidation of o-chlorophenol over Co2XAI(X=Co,Mg,Ca,Ni)hydrotalcite-derived mixed oxide catalysts

A cobalt-based hydrotalcite-like compound was prepared using a constant-pH coprecipitation method.Cobalt-transition metal oxides(Co2XA10,X=Co,Mg,Ca and Ni)were investigated for the deep catalytic oxidation of o-chlorophenol as a typical heteroatom contaminant containing chlorine atoms.The partial substitution of Co by Mg,Ca or Ni in the mixed oxide can promote the catalytic oxidation of o-chlorophenol.The Co2MgA10 catalyst presented the best catalytic activity,and could maintain 90%o-chlorophenol conversion at 167.1℃,compared only 27%conversion for the Co3A10 catalyst.The results demonstrated that the high activity could be attributed to its increased low-temperature reducibility,rich active oxygen species and excellent oxygen mobility.In the existence of acid and base sites,catalysts with strong basicity also showed preferred activity.The organic by-products generated during the o-chlorophenol catalytic oxidation over Co2MgAlO catalyst included carbon tetrachloride,trichloroethylene,2,4-dichlorophenol,and 2,6-dichloro-p-benzoquinon,et al.This work provides a facile method for the preparation of Co-based composite oxide catalysts,which represent promising candidates for typical chlorinated and oxygenated volatile organic compounds.

Catalytic performance of ternary Mg-Al-Ce oxides for ethanol conversion into 1-butanol in a flow reactor

An investigation of hydrotalcite-derived ternary Mg-Al-Ce oxides as catalysts for vapour phase condensation of ethanol to 1-butanol in a flow reactor under atmospheric pressure was carried out.The Mg-Al-Ce oxide systems with Mg/(Al+Ce)ratio from 1 to 4 were synthesized and characterized by XRD,SEM,NMR,and XPS.The study of acid-base characteristics of the systems with different Mg/(Al+Ce)ratio by NH3/CO_(2)quasi-equilibrium thermal desorption techniques shows that the ratio of the catalyst oxide components(Mg,Al,Ce)can provide acid/base capacity ratio close to 3 for the effectivity of the target process.The highest selectivity 68%is reached over Mg-Al-Ce oxide catalyst with the ratio of Mg/(Al+Ce)=2.

Hydrogen Production Performances via Steam Reforming over Hydrotalcite Derived Catalyst: A Sustainable Energy Production Review

The review outcome represents the optimum catalytic conditions for the production of hydrogen using hydrotalcite derived catalysts. It covers dry and steam reforming of methane, steam reforming of methanol and ethanol to hydrogen. The review also revealed the specific properties of hydrotalcite derived catalysts for the reactions. Among catalyst investigated, Ni & Fe promoted Al-Mg containing hydrotalcite catalyst perform best (99%) for dry reforming of methane at 250°C. For steam methane reforming, Ni containing ca-aluminates hydrotalcite catalyst act as the best (99%) at 550°C. Cu-supported Zn-Al-containing catalyst performs the best (99.98%) for steam reforming of methanol at 300°C whereas Cu impregnated Mg-Al containing hydrotalcite is the best (99%) for steam reforming of ethanol at 200°C - 600°C. It’s (HT) tunable and versatile textural and morphological properties showed excellent catalytic performances for different industrial processes and in sustainable hydrogen production.

Solvent-free partial oxidation of cyclohexane to KA oil over hydrotalcitederived Cu-MgAlO mixed metal oxides

A highly efficient and stable hydrotalcite-derived Cu-MgAlO catalyst was developed for the partial oxidation of cyclohexane with molecular oxygen.The physical–chemical properties of Cu-MgAlO catalysts were studied,and the results indicated that the copper component had been successfully introduced into the hydrotalcite unit layer structure.The catalytic reaction results showed that copper as the active species could activate CAH bond and effectively promote the decomposition of cyclohexyl hydroperoxide(CHHP)to the mixture of cyclohexanol and cyclohexanone(KA oil).8.3%of cyclohexane conversion and 82.9%of selectivity for KA oil were obtained over 9%Cu-MgAlO catalyst at 150℃with 0.6 MPa of oxygen pressure for 2 h.Especially,its catalytic performance was still stable after five runs.