Abstract

Photocatalyst membranes prepared with semiconductor nanoparticles embedded in polymer film offer a 

convenient approach to direct the electron and hole flow and separate reduction and oxidation products. 

We have now embedded In2S3 and ZnS semiconductor nanoparticles in a Nafion membrane to induce 

photocatalytic reactions using visible light. In addition, we have incorporated a viologen redox relay within 

the membrane to facilitate electron transfer to thionine (TH) dissolved in water. By inserting the 

photocatalytic membrane in an H-cell, we can separate the oxidation and reduction products and track 

the electron flow using steady state photolysis and transient absorption spectroscopy. The enhanced 

charge separation in In2S3 and ZnS heterostructure at 50:50 loading allowed us to maximize the electron 

transfer yield. Directing such vectorial charge transfer in a photocatalytic membrane will be useful in 

suppressing undesired side reactions (e.g. reoxidation of a reduced product) and facilitating product 

separation.