pH Independent and Efficient Photocatalytic Systems Enabled by Reaction Interface Microenvironment Regulation†

Photocatalysis is a promising green approach for water purification. The diversity of water pH values is a key factor that restricts its practical application since pH affects the adsorption of organic molecules, the stability of catalysts and photocatalytic performance. Here, we report a pH–independent, efficient and stable photocatalytic system with a liquid (water)–liquid (oil)–solid (semiconductor) (L–L–S) triphase interface microenvironment. The system is fabricated by coating a thin layer of silicon oil on the surface of ZnO nanowire arrays, a model chemically unstable semiconductor in both acidic and alkaline solutions. We show that the unique interface makes the dye adsorption pH independent and prevents the semiconductor from being corroded by strong acidic/alkaline solutions, leading to a stable and efficient photocatalytic reaction over a wide pH range (1—14). These findings reveal a promising path for the development of high-performance catalysis systems applicable in complex water environments.