With increasing demands of sustainable energy, solar energy is particularly attractive due to its abundance and clean nature. In that context, photoelectrochemical system is drawing considerable attention in solar energy conversion, photocatalysis, and water splitting. In the photoelectrochemical system, metal-ligand complexes can offer a new opportunity as a next-generation photo-driven materials with its outstanding optical property and photocatalytic activity. However, its low photocatalytic activity by the limitation of the photoinduced electrons within a photoelectrode has posed a significant challenge in the field. In this study, we suggest a multilayered bifunctional photoelectrode for overall water splitting consists of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) composed of ruthenium (Ru) complex and nanosized graphene oxide (nGO) using layer-by-layer (LbL) assembly. In particular, the synergistic role of each component within the multilayered photocatalytic electrode was exploited; for example, the coordination complex of Ru with terpyridine ligand (TPY2Ru) was incorporated for generation of photoinduced electrons, while nGO was employed to support the electron transfer within the photoelectrode. It was found that the LbL assembled bifunctional photoelectrode of (TPY2Ru/nGO)n showed a high photocurrent density, 4.28 μA/cm2 for OER and 28.42 μA/cm2 for HER. In addition to significant photocatalytic activity in overall water splitting, bifunctional photoelectrode prepared in a molecular level demonstrated high mechanical flexibility with only ~ 4% changes in the photocurrent density after 1000 bending cycles. We anticipate that this novel strategy for designing and assembling an efficient bifunctional photoelectrode for overall water splitting can offer new insights for flexible electrode engineering and photocatalytic devices for clean energy sources.

Coordination complex based artificial multilayered bifunctional photoelectrode for overall water splitting.

2019 Spring National Meeting

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