Dye–catalyst dyads for photoelectrochemical water oxidation based on metal-free sensitizers

Abstract

Dye–catalyst dyads based on metal-free dyes were prepared for dye-sensitized photoanodes in photoelectrochemical water splitting, showing a top ranked faradaic efficiency for O2 generation up to 95%.

Photoelectrochemical Cells with a Pyridine-Anchored Bilayer Photoanode for Water Splitting

“…The DSPEC constructed with the finally prepared photoanode is used to split water into H 2 and O 2 under visible-light irradiation and a photocurrent density of 200 μA/cm 2 is acquired during the photolysis. This photocurrent density is moderate compared with those of the most reported DSPECs (<500 μA/cm 2 ). ,,,, The overall performance stability is not high, which is similar to most molecular DSPECs that are limited by the low adsorption stability of the carboxyl and phosphate anchoring groups in aqueous media. However, the molecular assembly of the organic linker DAPyr through pyridine groups shows better stability than that of the phosphate group here.…”

“…A dye-sensitized photoanode based on metal-free organic dyes and a ruthenium molecular catalyst was reported to show a photocurrent density of ca. 100 μA/cm 2 and an optimized Faradaic efficiency of 88% . The carboxylic or phosphate group was used as the anchoring group in all of these examples.…”

“…The carboxylic or phosphate group was used as the anchoring group in all of these examples. An issue of using these anchoring groups is that it is usually troublesome to incorporate these groups in synthesis and the resulting films suffer from poor stability in aqueous media. − In this context, we have recently designed a series of organic molecules with multiple terminal pyridine groups as anchors to link functional molecules to the surface of metal or metallic oxide. − This strategy was used to fabricate stable electrochromic films and photoanodes and photocathodes with excellent stability in aqueous media for the construction of DSPECs for H 2 production. In addition to our efforts, the pyridine anchoring strategy has been employed by others on the investigation of interfacial photocatalytic reactions in recent years. ,− …”

KuQuinones: a ten years tale of the new pentacyclic quinoid compound

“…Metal-free organic sensitizers are emerging as a new alternative to metal complexes, such as ruthenium( ii ) polypyridine derivatives. 73 Porphyrins, 74–76 perylenediimide 77–79 derivatives, donor–π–acceptor molecules 80–85 and calixarenes 86 have been exploited with different WOCs, obtaining good to excellent photocurrent and faradaic efficiencies, in terms of oxygen production (Table 1, Fig. 12).…”

A covalently linked nickel(ii) porphyrin–ruthenium(ii) tris(bipyridyl) dyad for efficient photocatalytic water oxidation

“…24,25 One very promising approach to overcome this issue is the development of photoelectrochemical cells (PECs), where the catalyst and the PS are adsorbed onto an inorganic semiconductor electrode. 26 In these devices, the adsorbed PS harvests solar energy and injects an electron into the conduction band of the semiconductor. Subsequently, the generated radical cation PS +Á is reduced from the WOC, while repeating cycles of this process results in a highly oxidized catalytic moiety, able to convert water molecules into protons and molecular oxygen.…”