Multimodal Analysis of Light-Driven Water Oxidation in Nanoporous Block Copolymer Membranes

Heterogeneous light-driven catalysis is a cornerstone of sustainable energy conversion. Most catalytic studies focus on bulk analyses of the hydrogen and oxygen evolved, which impede the correlation of matrix heterogeneities, molecular features, and bulk reactivity. Here, we report studies of a heterogenized catalyst/photosensitizer system using a polyoxometalate water oxidation catalyst and a model, molecular photosensitizer that were co-immobilized within a nanoporous block copolymer membrane. Via operando scanning electrochemical microscopy (SECM), light-induced oxygen evolution was determined using sodium peroxodisulfate (Na2S2O8) as sacrificial electron acceptor. Ex situ element analyses provided spatially resolved information on the local concentration and distribution of the molecular components. Infrared attenuated total reflection (IR-ATR) studies of the modified membranes showed no degradation of the water oxidation catalyst under the reported light-driven conditions.

Automated summary

This study focused on a nanoporous block copolymer membrane which immobilized a polyoxometalate water oxidation catalyst and a molecular photosensitizer. The light-induced oxygen evolution was observed using operando scanning electrochemical microscopy, and the modified membranes showed no degradation of the catalyst under the reported light-driven conditions.