Synthesis,Characterization And Catalytic Properties Of Layered Double Hydroxides

Hydrotalcite-like compounds(HTLCs),also called layered double hydroxides(LDHs),because of their special structure,they have exhibited excellent properties as one of catalytic materals.In this paper,A series of hydrotalcite-like compouds were prepared via co-precipitation process and calcined to obtain their derivatives layered double oxides(LDO).Powder X-ray diffraction(PXRD),TEM,SEM and FT-IR spectroscopy were used in research of the composition and structure of products.This paper presents a detailed study on its Catalytic Properties,including:1.Zn/Al-(x)-HTLCs,Ni/Ti-(x)-HTLCs and Zn/Ni/Al-(x)-HTLCs were prepared by co-precipitation method,and P-Zn/Al-(x)-HTLCs were synthysized by the ion-exchange method and calcined to obtain their derivatives layered double oxides..the photocatalytic properties of layered double oxides were discussed by photodegradation of methyl orange,methylene blue,rhodamine B,It had been found that Zn/Al-LDO>P-Zn/Al-LDO>POMs;both Ni/Ti-LDO and Zn/Ni/Al-LDO exhibit efficient catalytic activities,the degradation rate of methyl orange can reach 98%within 30 min by Ni/Ti-(4)-LDO and the degradation rate of methyl orange and methylene blue(MB)can reach 97%within 60 min and rhodamine B can reach 91%within 100 min by Zn/Ni/Al-(1:1:1)-LDO.It has not been correlative literature reports that Ni/Ti-LDO and Zn/Ni/Al-LDO had been used for photocatalysis at home and aboard at present.2.Mg/Al-(x)-HTLCs and Li/Al-(x)-HTLCs were prepared by co-precipitation method,and calcined to obtain Mg/Al-(x)-LDO and Li/Al-(x)-LDO,which were applied’ in the producation of biodiesel via the transesterification of soybean oil and methanol.It was found that the Mg/Al-(3)-LDO calcined at 450 ℃ gave the best catalytic performance,under the follow conditions:0.5%catalyst,15 methanol/soy-bean ratio,reacting at 65 ℃ for 2 h,the highest yield(97.4%)of biodiesel was acquired.And the Li-Al-(13)-LDO calcined at 400 ℃ gave the best catalytic performance.Under the follow conditions:0.5%catalyst,15 methanol/soybean ratio,reacting at 65 ℃ for 2 h,the highest yield(96.5%)of biodiesel was acquired.Moreover,both Mg/Al-(3)-LDO and Li-Al-(13)-LDO could be recovered and maintained good yield(90%)for three reused times.3.P-Zn/Al-(x)-HTLCs can be synthesized by ion-exchange method and calcined to obtain P-Zn/Al-(x)-LDO,which were applied in the producation of DIOP via the esterification of isooctyl alcohol and phthalandione.Under the follow conditions:0.76%catalyst,2.5 isooctyl alcohol/phthalandione ratio,reacting at 180 ℃,the yield of DIOP could reach 92.8%for(reaction time 4.5 h),and 97.9%(reaction time 10 h).