Interfacial engineering in Pickering emulsion photocatalytic microreactors: From mechanisms to prospects

Considering the immiscible, limited-contact surfaces and confined active sites problems, the multiphase catalytic systems often confront many challenges. Due to the natural barriers of phase separation, the Pickering emulsion (PE) microreactors were regarded as an effective technique to solve above problems. The combination of photocatalytic reaction and PE system shows many advantages, such as evitable particle aggregation, large specific surface areas, uniform active sites, etc. However, relevant analyses of photocatalysis in PE system have not been summarized in detail. Herein, we reviewed researches concerning categories of photocatalyst, photocatalytic mechanisms and potential applications in PEs, especially for the significant influence mechanisms in photocatalytic efficiency of PE system. Except for the existing photocatalytic degradation and reforming applications, the PE microreactors are also promising for more photoelectronic fields, such as biofuels upgrade, process index detection and renewable energy, etc. We expect that the inductive contents in PE interfacial photocatalysis will produce more profound effects on developments and applications in industry.