A novel Ag3PO4-CaO composite photocatalyst with enhanced photocatalytic activity was synthesized and utilized for degradation of ammonia from aqueous solution under sunlight. Ag3PO4 was prepared by pre- cipitation met...A novel Ag3PO4-CaO composite photocatalyst with enhanced photocatalytic activity was synthesized and utilized for degradation of ammonia from aqueous solution under sunlight. Ag3PO4 was prepared by pre- cipitation method, and the composite of AgjPO4-CaO was prepared via impregnation method. Utilization of eggshell for CaO synthesis provided a cost-effective and environmental friendly way for the hetero- geneous catalyst production. The as-prepared photocatalysts were characterized by FT-IR, FE-SEM, TEM, EDX, UV-vis and PL Results show that the Ag3PO4-CaO samples have excellent photocatalytic perfor- mances in the wide visible-light region. The effect of operating parameters like the content of Ag3PO4 in composite, initial ammonia concentration, pH of solution, catalyst dosage and oxygen supply was investi- gated. The photoeatalyst with 60 wt% content of Ag3PO4 had a high photocatalytic performance, because a low content of Ag3PO4 causes weak light absorption, and the excess amount of it results in serious electron-hole recombination due to the aggregation of AgjPO4 particles. The maximum ammonia degra- dation （about 70%） was achieved in 340 mg/L of ammonia, pH 11, and 1.25 g/L of catalyst in the presence of pure oxygen. In comparison to Ag3PO4, 60 wt% AgjPO4-CaO had a good stability and it could have been easily separated from the solution for recycling.展开更多
文摘用电化学方法制备Ag3PO4/Ni薄膜,以扫描电子显微镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶相结构、光谱特性及能带结构进行了表征,以罗丹明B为模拟污染物对薄膜的光催化活性和稳定性进行了测定,采用向溶液中加入活性物种捕获剂的方法对薄膜光催化降解机理进行了探索。结果表明:最佳工艺下制备的Ag3PO4/Ni薄膜具有致密的层状表面结构,是由多晶纳米颗粒构成的薄膜。薄膜具有较高的光催化活性和突出的光催化稳定性,可见光下催化作用60 min,薄膜光催化罗丹明B的降解率是多孔P25 Ti O2/ITO纳米薄膜(自制)的2.3倍;在保持薄膜光催化活性基本不变的前提下可循环使用6次。给出了可见光下薄膜光催化降解罗丹明B的反应机理。
文摘采用电化学方法制备Ag3PO4/Ni薄膜,以扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶相结构、光谱特性及能带结构进行表征,以罗丹明B为模拟污染物对薄膜的光电催化活性和稳定性进行测定,采用向溶液中加入活性物种捕获剂和通氮除氧方法对薄膜的光催化降解机理进行探索,并提出光电催化降解罗丹明B的反应机理。结果表明:最佳工艺下制备的Ag3PO4/Ni薄膜具有致密的层状表面结构,是由多晶纳米颗粒构成的薄膜。该薄膜具有显著的光电催化活性,在最佳阳极偏压下,光电催化罗丹明B的降解率是多孔P25 Ti O2/ITO薄膜的6.69倍;相对于未加偏压的光催化,降解率提高了5.34倍,并且具有突出的光电协同效应。同时,该薄膜具有优异的光催化和光电催化稳定性。在0.1 V阳极偏压下,可使光催化稳定性提高近一倍。
文摘A novel Ag3PO4-CaO composite photocatalyst with enhanced photocatalytic activity was synthesized and utilized for degradation of ammonia from aqueous solution under sunlight. Ag3PO4 was prepared by pre- cipitation method, and the composite of AgjPO4-CaO was prepared via impregnation method. Utilization of eggshell for CaO synthesis provided a cost-effective and environmental friendly way for the hetero- geneous catalyst production. The as-prepared photocatalysts were characterized by FT-IR, FE-SEM, TEM, EDX, UV-vis and PL Results show that the Ag3PO4-CaO samples have excellent photocatalytic perfor- mances in the wide visible-light region. The effect of operating parameters like the content of Ag3PO4 in composite, initial ammonia concentration, pH of solution, catalyst dosage and oxygen supply was investi- gated. The photoeatalyst with 60 wt% content of Ag3PO4 had a high photocatalytic performance, because a low content of Ag3PO4 causes weak light absorption, and the excess amount of it results in serious electron-hole recombination due to the aggregation of AgjPO4 particles. The maximum ammonia degra- dation （about 70%） was achieved in 340 mg/L of ammonia, pH 11, and 1.25 g/L of catalyst in the presence of pure oxygen. In comparison to Ag3PO4, 60 wt% AgjPO4-CaO had a good stability and it could have been easily separated from the solution for recycling.
