Applying microreactor technology to photocatalytic reactions is a novel and potential technical innovation. Photocatalytic planar microreactors were fabricated by metal etching technology

and copper ion doped TiO2 was immobilized as coatings by the sol-gel method. X-ray diffraction

scanning electron microscope and UV-visible diffuse reflection were used for characterization of photocatalyst. The microreactors were tested for the degradation of methyl orange and the optimal doping concentration of copper ion was found to be 0.04% (mole ratio to Ti). The degradation ratio of methyl orange with an initial concentration of 10 mg·L-1 could reach 45% within 90 s in the microreactor. Degradation ratios of methyl orange in microreactors under controlled irradiation were measured

and the copper ion doped photocatalytic microreactors showed better utilization of irradiation energy. The study of kinetics illustrated that the degradation of methyl orange in the microreactors was a first order reaction of incomplete oxidation with a much greater rate constant (k) comparing to regular reactors. The rate constant increased with the decreasing of initial concentration (C0)

and there was a good linear relationship of lnk and lnC0.