CAJ | 학술논문

采用无机盐溶胶-凝胶法,以硝酸锌、硝酸铁、硝酸铬、硝酸锰为原料,柠檬酸为络合剂,在空气气氛中,制得干凝胶经600 ℃热处理制备了系列锌尖晶石ZnM2O4(M=Cr,Mn,Fe)纳米粉体.用X射线衍射仪和透射电子显微镜分别对粉体的结构、形貌进行了分析和表征.结果表明:制备的ZnCr2O4,ZnMn2O4和ZnFe2O4粉体均为单一尖晶石晶体结构,呈不规则颗粒状,粒径为10～35 nm.通过紫外-可见漫反射吸收光谱,得到吸收极限波长分别红移至400,600,680 nm,具有较好的可见光响应.在高压汞灯(λ＞400 nm)和太阳光照射下,纳米ZnM2O4(M=Cr,Mn,Fe)粉体对甲基橙、酸性红B、活性艳红K-2G等有机模拟降解液的2h脱色降解率分别达到80%,57%和39%以上,表明锌尖晶石ZnM2O4(M=Cr,Mn,Fe)光催化剂具有良好的可见光催化活性,并随禁带宽度Eg的减小,催化活性增加.根据无机固体化学能带理论和晶体场理论,依据M-O电负性和d电子数量讨论了它们光催化活性的差别.
채용무궤염용효-응효법,이초산자、초산철、초산락、초산맹위원료,저몽산위락합제,재공기기분중,제득간응효경600 ℃열처리제비료계렬자첨정석ZnM2O4(M=Cr,Mn,Fe)납미분체.용X사선연사의화투사전자현미경분별대분체적결구、형모진행료분석화표정.결과표명:제비적ZnCr2O4,ZnMn2O4화ZnFe2O4분체균위단일첨정석정체결구,정불규칙과립상,립경위10～35 nm.통과자외-가견만반사흡수광보,득도흡수겁한파장분별홍이지400,600,680 nm,구유교호적가견광향응.재고압홍등(λ＞400 nm)화태양광조사하,납미ZnM2O4(M=Cr,Mn,Fe)분체대갑기등、산성홍B、활성염홍K-2G등유궤모의강해액적2h탈색강해솔분별체도80%,57%화39%이상,표명자첨정석ZnM2O4(M=Cr,Mn,Fe)광최화제구유량호적가견광최화활성,병수금대관도Eg적감소,최화활성증가.근거무궤고체화학능대이론화정체장이론,의거M-O전부성화d전자수량토론료타문광최화활성적차별.
Zinc spinel ZnM2O4 (M=Cr, Mn, Fe) nanoparticles were prepared from dry gel using an inorganic salt sol-gel method and calcination in air at 600 ℃. The crystalline structure and morphology were characterized by powder X-ray diffraction and transmission electron microscopy. The results indicate that ZnCr2O4, ZnMn2O4 and ZnFe2O4 powders possess asingle spinel-type structure.The particles have an irregular shape with the sizes of 10-35 nm. The absorption edge wavelengths of ZnCr2O4, ZnMn2O4 and ZnFe2O4 crystals are 400, 600 nm and 680 nm, respectively, in ultraviolet-visible diffuse reflectance spectra. The photocatalytic degradation property of ZnM2O4 (M=Cr, Mn, Fe) nanoparticles was investigated by using methyl orange, acid red B and reactive red K-2G as model pollutants under the irradiation of a mercury-vapor lamp (λ＞400 nm) or sunlight. The degradation rates of the above three dyes by ZnM2O4(M=Cr, Mn, Fe) are over 80％, 57％ and 39％, respectively within 2 h. It is found that ZnM2O4 (M=Cr, Mn, Fe)has a novel photocatalytic behavior for dyes under visible light irradiation. And with the decrease of band gap energy (Eg) of ZnM2O4 (M=Cr, Mn, Fe), the catalytic activity increases steadily. The possible reason for this activity change is discussed from the crystal field theory and energy band theory.