以二氧化钛为光催化剂 ,研究了溶液的 pH值、铬酸根离子的初始浓度、通入的气体种类、氧化钛的载量等因素对铬酸根离子降解率的影响 .同时合成了粒径小于 1 0nm的锐钛矿相和金红石相氧化钛纳米晶来考察晶相和尺寸效应对降解率的影响 .结果表明 ,锐钛矿相的催化活性高于金红石相 ,两者的催化活性均大大高于市售的氧化钛微粉 Titanium dioxide as a photocatalyst, the solution pH, the initial concentration of chromate ions, the introduction of gas species, the amount of titanium dioxide and other factors on the degradation rate of chromate ions.At the same time the particle size of less than10nm Anatase phase and rutile phase titania nanocrystals to investigate the effect of crystal phase and size effect on the degradation rate.The results show that the catalytic activity of anatase phase is higher than that of rutile phase, Sales of titanium oxide powder