Cu2 + . cr3 + were selected with different weight ratio doping in tio2 to study the photocatalyst modifying in this paper . the experiments of degradation methylene blue showed that the doping results were quantitatively correlated with the transition metal ion radii . their electronic configuration 对次甲基蓝的降解实验表明掺杂离子的修饰效果与过渡金属离子的离子半径、外围电子构型、氧化还原电位和离子浓度等因素有关，质量比为0 . 5的fe ~ ( 3 + )掺杂对次甲基蓝的降解效率最高。
