The reported papers about photocatalytic reaction are usually carried out in a conventional batch reactor. The reaction volume usually ranges from a few millimeters to several tens millimeters, thus producing a lower reaction efficiency. In recent years, a type of photochemical reaction based on a continuous flow microreactor which is called microfluidic technology has been extensively studied.

A microfluidic chip based on symmetrical metal-cladding waveguide was firstly proposed to realize efficient photocatalysis. The chip was manufactured by conventional soft lithography technique. The light intensity was largely enhanced due to the excitation of several oscillating modes. Compared with traditional microfluidic photocatalysis, symmetrical metal-cladding waveguide based microfluidic photocatalysis demonstrated an increased efficiency of about 40%.

Shu Zhu, Hailang Dai, Bei Jiang, Zhenhua Shen and Xianfeng Chen, Efficient microfluidic photocatalysis in a symmetrical metal-cladding waveguide, Phys. Chem. Chem. Phys., 18, 4585--4588 (2016)