C-O官能团修饰的CaMoO_(4)光催化剂的合成与光催化活性研究

Synthesis and photocatalytic activity of a CaMoO_(4) photocatalyst modified with C-O functional groups

采用溶胶凝胶法制备了对盐酸金霉素具有高效降解活性的CaMoO_(4)光催化剂。通过多种表征手段,研究了CaMoO_(4)光催化剂的相结构、纯度、官能团、表面形貌、光学性质和光催化活性。结果表明,CaMoO_(4)光催化剂为四方相,其样品中存在少量的C-O官能团;颗粒近似呈球形,由大颗粒和细颗粒组成;其具有高的可见光响应能力,光学带隙值为3.21 eV。以盐酸金霉素为目标降解物,在不同的药品质量浓度、催化剂含量、pH值条件研究了CaMoO_(4)光催化剂降解盐酸金霉素的光催化活性。结果表明,盐酸金霉素质量浓度为200 mg/L、催化剂含量1 g/L和pH值为7时,CaMoO_(4)光催化剂的降解百分比达到了94%。结合实验结果和能带理论,提出了CaMoO_(4)光催化剂降解盐酸金霉素的光催化机理。机理研究表明,C-O官能团在反应过程中为电子提供额外的能量使其跃迁到CaMoO_(4)光催化剂的导带,促进电子空穴对的产生;空穴、羟基自由基和超氧自由基是促进盐酸金霉素降解的关键因素。

A CaMoO_(4) photocatalyst with high activity for degradation of aureomycin hydrochloride was prepared by sol-gel method.The phase structure,purity,functional group,surface morphology,optical properties and photocatalytic activity of the CaMoO_(4) photocatalyst were investigated by various characterization methods.The results showed that the CaMoO_(4) photocatalyst was tetragonal phase,and a small amount of C-O functional groups were present in the sample.The particles were approximately spherical,which consisted of large particles and fine particles.It had high visible-light response with an optical band gap value of 3.21 eV.The photocatalytic activity of CaMoO_(4) photocatalyst was studied at different drug concentrations,catalyst dosages and pH values using aureomycin hydrochloride as the target for degradation.The results showed that the degradation percentage reached 94%at the drug mass concentration of 200 mg/L,photocatalyst dosage of 1 g/L and pH of 7.The photocatalytic mechanism of the CaMoO_(4) photocatalyst was proposed based on experimental results and band theory.The mechanism study showed that the C-O functional groups provided extra energy for electron transition to the conduction band of the CaMoO_(4) photocatalyst and promoted the generation of electron hole pairs.Holes,hydroxyl radicals and superoxide radicals were the key factors to promote the degradation of aureomycin hydrochloride.