Dynamics and Photochemical H₂ Evolution of Dye–NiO Photocathodes with a Biomimetic FeFe-Catalyst

Abstract

Mesoporous NiO films were cosensitized with a coumarin 343 dye and a proton reduction catalyst of the [Fe 2 (CO) 6 (bdt)] (bdt = benzene-1,2-dithiolate) family. Femtosecond ultraviolet−visible transient absorption experiments directly demonstrated subpicosecond hole injection into NiO from excited dyes followed by rapid (t 50% ∼ 6 ps) reduction of the catalyst on the surface with a ∼70% yield. The reduced catalyst was long-lived (2 μs to 20 ms), which may allow protonation and a second reduction step of the catalyst to occur. A photoelectrochemical device based on this photocathode produced H 2 with a Faradaic efficiency of ∼50%. Fourier transform infrared spectroscopy and gas chromatography experiments demonstrated that the observed device deterioration with time was mainly due to catalyst degradation and desorption from the NiO surface. The insights gained from these mechanistic studies, regarding development of dye−catalyst cosensitized photocathodes, are discussed. Letter http://pubs.acs.org/journal/aelccp

Solar H2 evolution in water with modified diketopyrrolopyrrole dyes immobilised on molecular Co and Ni catalyst–TiO2 hybrids

“…Light-driven H 2 evolution with organic dyes in combination with a metal oxide semiconductor has been previously reported, but these systems required either a Pt co-catalyst, a p-type semiconductor electrode, organic solvents or an anchor-free diffusional dye. 8,27–30 Only few studies are available with organic chromophores under DSP conditions and even less with commonly used aqueous electron donors, such as triethanolamine (TEOA) or ascorbic acid (AA), or with a molecular catalyst in a semi-heterogeneous photocatalytic scheme. 11,31–34 …”

A Functional Hydrogenase Mimic Chemisorbed onto Fluorine‐Doped Tin Oxide Electrodes: A Strategy towards Water Splitting Devices

“…Preparation of electrodes decorated with hydrogenase model complexes has been reported, although hydrogen evolution studies with these modified electrodes have met with limited success . In 2005, Vijaikanth et al.…”

“…However, the stability of the amide bond under the applied highly reductive and acidic conditions was demonstrated by immobilization of ferrocene moieties by the same strategy. In 2016, a NiO‐modified electrode functionalized with a diiron catalyst was shown to evolve hydrogen in a photocatalytic fashion . In recent years, diiron model complexes featuring benzenedithiolate bridges have become increasingly popular as they impart interesting tunable electronic properties to the hydrogenase models .…”

An Indacenodithieno[3,2‐b]thiophene‐Based Organic Dye for Solid‐State p‐Type Dye‐Sensitized Solar Cells

“…[2] p-DSCs [3][4][5][6][7] have subsequently attractedi ntensei nterest from scientists owing to their potentiala pplications in tandemd yesensitized solar cells (t-DSCs), [8][9][10][11][12][13][14] as well as in dye-sensitized solar fuel devices (DSSFDs). [15][16][17][18][19][20][21][22][23][24] In 2016, our group fabricated the first solid-state p-DSCs (p-ssDSCs), incorporating an organic dye P1 as the photosensitizer and PCBM as the electron-transport material( ETM), in which we completelya bandoned the liquid redox couple and obtained an impressive photovoltage of 620 mV. [25] With the improved performance of p-ssDSCs, there is potential to build tandem solid-state DSCs (t-ssDSCs), as well as to improve the performanceo fD SSFDsb ys uppressing charge recombination loss between holes in the p-type semiconductor substrate and electrons in the reduced catalysts.…”