untitled Synthesi Adly Abdel a Inorganic Chemi b Electron Microsc *Corresponding a E‐mail address: go ARTICLE INFO Received: 20 Apr Received in revis Accepted: 22 July Online: 31 Decem KEYWORDS Cerium phosphat Zinc phosphate Calcinations X‐ray diffraction IR TEM 1. Introductio Nowadays attracting atte problems such damages to acceleration o sunscreen mat sunscreen pro and inorganic may pose a concentration irritation on th estrogenic ac ultrafine titan been applied a zinc oxide are the former is harmful for th the products problem to for Although has high cataly as applied in cleaning cata compounds w low side effe attention has b their potential Hanna et phosphate wit the effects of v and sintering and particle si mixtures of s and mic la Hannaa, S istry Department, N copes and Thin Film uthor at: Inorganic ohamora@yahoo.c ORMATION il 2011 ed form: 11 July 20 y 2011 mber 2011 te on s, the damagin ention because h as photo‐deg human health of aging, cance terials for UV s oducts come in c compounds [ safety problem s, because som he skin of sensi ctivities [5,6]. nium oxide, zin as effective sun e popular inorg known as an ex he skin and som . The latter rm Zn2+ ions [1 cerium oxide e ytic activities fo oxidation, com alysts [12]. S with excellent u ect are needed been paid to the l applications fo t al. [16], pr th monoclinic o various factors temperatures ize of the obtai cerium‐zinc p Eu ISSN 2153‐ Europ J crostructu Sahar Moham National Research C m Department, Nati c Chemistry Depart com (M.A. Sherief). 011 ng effects of U UV rays in su gradation of org h e.g. causing er, etc. [1‐3]. T hielding have b two basic form [4]. However, m when they me of organic U tive individuals Inorganic su nc oxide and nscreens [7‐9]. ganic sunscree xcellent photoc metimes affects has a photoin 0,11]. exhibits minim or oxidation of o mbustion and a So, the produ ultraviolet abs d. In recent y e rare earth ph or anti‐UV mate epared pure or hexagonal st s such as pH, pr on the morph ined product. In phosphates by uropean Journal Europe 2249 (Print) / IS DOI:10.5155 pean Jo Journal home ure studie med Mousaa Centre, Dokki, Cairo ional Research Cen tment, National Res ABSTRACT A system of C chemical reacti cations (x) in th for 2 hrs. The e (XRD) and infra investigated em analysis (TGA) morphology, cr results indicate importance of Z UV rays have unlight causes m ganic materials g sunburn, su Therefore, exce been developed ms: synthetic org organic sunscr are used at UV absorbers c s and demonstr unscreens, suc cerium oxide, Titanium oxide en agents. How catalyst that ma other ingredien nduced dissolu al photocatalys organic compou automotive exh ucing of inorg orption ability years, conside osphates becau erials [13‐15]. phases of ce ructure and stu recursor's mate hology, crystal n the present w y substituting of Chemistry 2 ( ean Journal of Ch SSN 2153‐2257 5/eurjchem.2.4. ournal o epage: www.e es of nano a, Marwa Ad o‐11787, Egypt ntre, Dokki, Cairo‐1 search Centre, Dok Ce(SO4)2.4H2O, Z on between the he range of x = effect of calcinati ared spectroscop mploying differ . The transmiss rystallinity and ed that the crys Zn, Ce phosphate been many s and untan, ellent d. The ganic reens high cause rative h as have e and wever, ay be nts in ution sis, it unds, haust ganic y and rable use of erium udied erials linity work, Ce3+ catio subs mor of th usin 2. Ex 2.1. C Zn(x co‐p acet cont amo reac stirr sepa and calci the phos Table X val 0.0 0.2 0.4 0.6 0.8 1.0 2.2. T perf (4) (2011) 503‐5 hemistry (Online)  2011 503‐508.441 of Chem eurjchem.com o‐sized ce el Sheriefa,* 1787, Egypt kki, Cairo‐11787, Eg Zn(CH3COO)2.2H precursor mate 0.0‐1.0. The obt ion on the produ py (IR). The the rential scanning sion electron m particle size o stallinity was im es return to their ons with Zn2+ stitution on t phology, therm he produced ph ng of their phosp xperimental Procedure Cerium‐zinc p x), (x = 0.0, 0.2, precipitation me ate dihydrate tinuous stirring ount of H3PO4 ction was adjust ring was contin arated by centr dried at 80 o ined at 650 oC f reactant mate sphates system e 1. The amount o lue Ce(SO4)2.4 5.0 4.0 3.0 2.0 1.0 0.0 Characterizat The structure a formed by X‐ray 508 1 EURJCHEM mistry m erium‐zin and Gehan gypt. Tel.: +20.10.52 H2O and phosph erials. The cerium tained gels were uced phases was ermal behaviors g calorimetric microscope (TEM f both dried an mproved by inc r using as UV‐sh cations were the produced mal behavior, c hases were stud phates as UV‐sh phosphates wit , 0.4, 0.6, 0.8 an ethod. Cerium were dissolve g at room tem was added dr ted by ammoni nued for 1 hr. T rifuging; then w oC. An amount for 2 hrs. Table erials, which m. f the reactant mate 4H2O (g) Zn(C 0.0 1.63 3.26 4.89 6.52 8.15 ion and the phases o y diffraction wh c phosph Mahmoud E 249230; fax: +20.2. horic acid was m cations were r e dried and calci s studied using X of only the drie (DSC) and the M) was used to nd calcined sam creasing the zin hielding agents. prepared and phases was rystallinity and died to draw so hielding agent i th different p nd 1.0) were p sulfate tetrahy ed in deionize mperature. Then ropwise. The p ia to be alkaline The formed pre washed with de t of each drie e 1 summarized were used fo erials. C4H6O4).2H2O(g) 3 6 9 2 5 of the produced here the diffrac ates Elkomyb 33335968. studied by the replaced by zinc inated at 650 oC X‐ray diffraction ed samples were ermogravimetric investigate the mples. The TEM nc contents. The d the effect of studied. The d particle sizes me light on the in the future. percentages of repared by the ydrate and zinc ed water with n, the required pH of the final e (pH ~ 8). The ecipitates were eionized water d sample was d the amount of or cerium‐zinc H3PO4 (mL) 0.84 1.00 1.18 1.35 1.51 1.68 d samples were tion patterns e c C n e c e M e f e s e f e c h d l e e r s f c e 504 Hanna et al. / European Journal of Chemistry 2 (4) (2011) 503‐508 Table 2. XRD results of calcinated Ce‐ Zn phosphates at 650 oC for 2 hr. X value Product phases Chem. composition Crys. structure 0.0‐0.2 Monazite CePO4 Monoclinic 0.4‐0.8 Monazite Zinc pyrophosphate Zinc phosphate CePO4 Zn2P2O7 Zn3(PO4)2 Monoclinic Orthorhombic Monoclinic 1.0 Zinc pyrophosphate Zinc phosphate Zn2P2O7 Zn3(PO4)2 Orthorhombic Monoclinic Figure 1. X‐ray diffraction patterns of as prepared and calcined cerium (a) and zinc (b) phosphate. were obtained by using Brukur D8 advanced X‐ray diffractometer with copper (Kα) radiation. Infrared measurements (IR) were recorded by JASCO‐FT/CR‐3000E infrared spectrophotometer in range from 4000 to 400 cm‐1 and the thermal analysis was performed by USA Perkin‐Elmer thermogravimetric up to 1000 оC with heating rate 10 оC/min. The morphology and the crystallinity of the produced samples before and after calcinations were examined by transmission electron microscope (TEM) Joel JEM 1230 working at 100 keV. Also Gatan program was used to calculate the d‐spacing from the selected area electron diffraction SAED patterns. 3. Results and discussion X‐ray powder diffraction patterns show that the prepared samples with x = 0.0‐0.4 are completely amorphous, while at x = 0.6 a weak crystalline phase becomes to appeared. For x = 0.8 and 1.0, the formed phases converted to well crystalline as shown in Figure 1. The analysis of the X‐ray patterns indicates that the formed phases are CePO4, ZnHPO4 (35‐574 card) and Zn3(PO4)2.4H2O(9‐49 card) at x = 0.8. Only two new phases of ZnHPO4 and Zn3(PO4)2.4H2O were formed at x = 1.0. By calcinating the samples at 650 оC for 2 hrs, only CePO4 with monoclinic structure (Monazite) was formed at x = 0.0 or 0.2 (83‐652). By the increase of zinc content to 0.4‐1.0 a mixture of different phases was formed depending on the ratio between Ce3+ and Zn2+. Table 2 represents the resulting phases. From X‐ ray results, it may be concluded that the substitution of Ce3+ by Zn2+ leads to improve the crystallinity of the produced samples. It seems that, the resulting CePO4 with trivalent cations while it added in the tetravalent state, may be due to the reduction of Ce4+ to Ce3+ in the acidic medium (Cerium, Wikipedia, the free encyclopedia). This behavior may be resulting from the energy of the inner level 4f of the cerium is nearly the same as that of the outer valance electrons [17]. Figure 2 and 3 represents the IR spectrum of the as ‐prepared samples and that calcinated at 650 оC for 2 hrs. For the as ‐prepared samples an absorption band in the range from 3000 to 3900 cm‐1 was observed. This band may be due to the stretching vibration of the OH groups which are attached with the moisture content or the phosphates groups, while the other band due to the H‐O‐H bending motion was observed in the region 1630‐1650 cm‐1 [18]. As observed frequently, the appearance of the absorption band for the phosphate compounds at 1400‐1450 cm‐1 was attributed to the carbonate group derived from the atmosphere during the preparation [19,20]. At x = 0.0, a series of bands are observed at 1067, 619 and 529 cm‐1 corresponding to P‐O stretching, O=P‐O bending and O‐P‐O bending mode vibration respectively. The appearance of these bands is characteristic to the formation of hydrous CePO4 as suggested previously by Hazal et al. [21]. For the sp on the position these band o additional ban to anti‐symm Zn3(PO4) form nearly the sam due to the sub instead of CeP occurred at 43 cm‐1 due to PO The IR sp difference fro depends on th the two absor disappeared d water of hydr band splitting observed. This groups in the Another splitt = 0.2‐1.0, whi following the spectra, two n cm‐1. These ba water content By raising the formed and orthophospha bands for the and continues For the as amounts (x = ectrum of samp n of the bands w occurred at 1 nds occurred at metric stretchin mation [22]. At x me trend, with bstitution of Ce PO4. For all prep 30 O4 vibration [23 pectra of the om the as ‐pr he amount of t rption bands at due to the eva ration by heati g at the wave n s splitting may e phosphates o ting at the rang ich is attribute effects of the a new absorption ands were attr t as proposed p zinc content (x is attributed ates (PO3 group phosphates co s to appear for a s ‐prepared sa = 0.0‐1.0), the Hanna et al. Figure 2. IR ple at x = 0.2, th which characte 1107, 617 and t 1036 and 473 ng mode of P x = 0.4‐1.0, the some shifts on e by Zn and form pared samples, 3]. calcinated sam repared sampl the added zinc t 3000‐3900 a poration of the ing. For the ca number range be due to the v of the monoclin e of 1200‐1090 d to the forma addition of zin n bands occurr ributed to the previously by A x = 0.8‐1.0), a ba d to the ap ps). In general mpound at ~4 all calcinated sa amples with di TG/DSC patter . / European Jour spectrum of as pre here are some s rize hydrous Ce d 536 cm‐1. S cm‐1 correspon PO4 group du e IR spectra beh n the band pos mation of Zn3(P an absorption mples exhibit s es. This differ cations. In gen nd 1630‐1650 e moisture and alcinated sampl 1050‐950 cm‐1 vibration of the nic symmetry 0 cm‐1 appeared ation of Zn2P2O c content on th red at 760 and P‐0‐P form and Assaaoudi et al. and at 593 cm‐1 ppearance of l, the characte 35 cm‐1 is obse amples. fferent Zn con rn was recorde rnal of Chemistry epared and calcine shifts ePO4; Some nding ue to haves sition PO4)2 band some rence neral, cm‐1 d the les, a 1 was e PO4 [21]. d at x O7. By he IR d 667 d the [24]. 1 was the eristic erved ntents ed in Figu from to ~ whic temp temp the appe note subs obse 300‐ from of th cont com At ~ obse phas crys endo due pyro two exot form T 650 x = x = amo selec the X y 2 (4) (2011) 50 ed samples of ceriu ure 4. Several s m the recorded ~100 оC and is ch is confirmed perature. The perature range loss of wate earance of an eworthy that th stitution with erved. As the ‐375 оC and ma m the amorphou his weight los tent increases; mpounds as indic ~600 оC, a ver erved, this may se of CePO4 to talline structur othermic peak w to the tran ophosphate by l weight loss ste thermic peaks, m of Zn3(PO4)2 a The TEM image оC for 2 hrs. a 0.0, the produ 0.2 a very w orphous was ob cted area electr X‐ray patterns. 03‐508 um phosphate. sequence weig patterns. The attributed to th d by a broad en e second wei e between 100 er of hydratio endothermic p hese results co zinc cations x = 0.2‐0.8, ay be due to the us state to the s shifts to low this may be d cated by the X‐r ry strong and y be due to the monoclinic or re [25]. At high was observed a nsformation o loss of the wate eps occurred an at the same reg and Zn2P2O7, re es of the as‐ pr are shown in F ced sample is weak crystalline bserved as clar ron diffraction p ht losses occur first weight los he loss of phys ndothermic pe ight loss occ to 250 оC and i on in agreem peak on the D onfirmed the IR a new weigh a weight los e transformatio crystalline form wer temperatu due to the form ray and the IR m sharp exother e conversion of r the formation h content of Zn at about 375 оC of ZnHPO4 t er content [26]. nd accompanied gion caused by spectively. repared and tha igure 5. It is ob in amorphous e phase embe rified from the pattern and not 505 rred as shown ss appeared up sosorbed water ak at the same urred in the is attributed to ment with the SC curve. It is R spectrum. By t losses were s occurred at on of the CePO4 m. The position re as the zinc mation of new measurements. rmic band was f the hexagonal n of Zn2P2O7 in n (x = 1.0), an , which may be to amorphous At 400‐525 oC, d by two broad y the crystalline at calcinated at bserved that at one phase. At edded into the corresponding t detected from n p r e e o e s y e t 4 n c w . s l n n e s , d e t t t e g m 506 As the co behavior was x = 0.8‐1.0, a h in the Z direct ontent of Zn c observed, whil high preferred o ion was happen Han Figure 3. Figure 4. TG cations increas le by increasing orientation of t ned. nna et al. / Europ IR spectrum of as G and DSC curves o e to 0.6, the g the zinc conte he crystalline p pean Journal of C prepared and calc of as prepared sam same ent to phase B mor part size Chemistry 2 (4) (2 ined samples zinc mples of cerium‐zin By calcination a phology reveal ticle size rang fr and shape of th (2011) 503‐508 phosphate. nc phosphate. at 650 оC for the led a monoclin rom 20 to 25 nm he crystalline st e samples with nic crystalline m. At x = 0.4, a tructure was ob x = 0.0‐0.2, the structure with change in both bserved. e h h A Fig Hanna et al. As prepared samp gure 5. TEM micro . / European Jour ples ographs of as pre rnal of Chemistry pared and calcine y 2 (4) (2011) 50 ed samples of cer 03‐508 Calcined samples X=0.0 X=0.2 X=0.4 X= 0.6 X =0.8 X=1.0 rium‐zinc phosph s hate. 507 508 Hanna et al. / European Journal of Chemistry 2 (4) (2011) 503‐508 In this case a rod like shaped particles and monoclinic crystalline structure with particle size ranging from 30 to 38 nm occurred. The formation of the nano‐rods structure may be due to homogent‐nucleation. The same behavior was observed for the calcinated samples with x = 0.6 and 0.8 with particle size 15 nm where increasing the Zn value will lead to preferred orientation to the crystalline phase which clearly observed from the very fine arrangement of the crystallite phase. It can be seen that the increasing of Zn to Ce improve the crystallinity and the growth tend to be in columnar structure, where the particle size tend to decrease with increasing the zinc ratio to Ce. At x = 1.0, the morphology shows a very fine zinc phos‐ phates with particle size ranging from 1 to 8 nm. The effect of the calcination on the morphology of the prepared samples at 650 оC is shown in Figure 5. 4. Conclusion The present work deals with studying the preparation and characterization of the produced phases by replacing Ce cations with Zn cations to be used as shielding agent in the future. A mixtures of Ce‐Zn phosphate (with x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) were prepared by reacting CeSO4.4H2O and Zn(CH3COO)2.2H2O with H3PO4. X‐ray results showed an amorphous phase for dried samples occurring at x = 0.0, 0.2 and 0.4. A very weak crystallinity occurred at x = 0.6. A complete crystalline form occurred at x = 0.8 and 1.0. For calcined samples, a polycrystalline phases were produced depending on x‐value. The thermal analysis TG/DSC indicated that the substitution of Ce3+ by Zn2+ shifted the crystallization of the produced phases to lower temperatures. 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