Controllable assembly of charge-transfer mediator enhances photocatalytic water oxidation

Researchers from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) have developed a method to assemble a charge-transfer mediator in photocatalysis, which could enhance surface charge-transfer efficiency and photocatalytic water oxidation activity. Water oxidation reactions require an uphill energy transformation and can limit the efficiency of photocatalytic water splitting reactions.

Although loading suitable water oxidation cocatalysts can enhance performance, the interfacial barrier between the semiconductor and the cocatalyst can hinder the transfer and use of photogenerated charges. The research team used partially oxidized graphene (pGO) as a charge-transferring mediator on the hole-accumulating facets of a lead chromate (PbCrO4) photocatalyst, inspired by natural photosynthesis. The pGO could be selectively assembled on the hole-accumulating facets of PbCrO4, and cobalt-complex Co4O4 molecules could be anchored on the pGO as a water oxidation cocatalyst.

The researchers confirmed that introducing the pGO charge transfer mediator could effectively suppress charge recombination at the interface, thus prolonging the lifetime of photogenerated charges and enhancing photocatalytic water oxidation performance. According to Prof. Li Rengui, this method provides a feasible way to accelerate charge transfer and charge utilization in semiconductor photocatalysis. The study was published in Angewandte Chemie International Edition on March 23.

Source:  Chinese Academy of Sciences

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