Finding the Way to Solar Fuels with Dye-Sensitized Photoelectrosynthesis Cells

Abstract

The dye-sensitized photoelectrosynthesis cell (DSPEC) integrates high bandgap, nanoparticle oxide semiconductors with the light-absorbing and catalytic properties of designed chromophore-catalyst assemblies. The goals are photoelectrochemical water splitting into hydrogen and oxygen and reduction of CO by water to give oxygen and carbon-based fuels. Solar-driven water oxidation occurs at a photoanode and water or CO reduction at a cathode or photocathode initiated by molecular-level light absorption. Light absorption is followed by electron or hole injection, catalyst activation, and catalytic water oxidation or water/CO reduction. The DSPEC is of recent origin but significant progress has been made. It has the potential to play an important role in our energy future.

A Noble‐Metal‐Free Heterogeneous Photosensitizer‐Relay Catalyst Triad That Catalyzes Water Oxidation under Visible Light

“…[2,3] Of these,d ye-sensitized photoelectrochemical cells (DS-PECs) utilize covalently coordinated chromophore-water oxidation catalyst (WOC) dyad assemblies [4][5][6] in an effort to mimic natural photosynthesis. [10][11][12][13][14][15][16][17][18][19] Although the use of robust heterogeneous assemblies such as oxides could be apromising solution to improve stability,the lack of complete control on the coordination of metal ions in oxide chemistry does not allow the preparation of oxidebased dyads. [7][8][9] Molecular ruthenium complexes (as photosensitizers and/or WOCs) remain the most widely used despite their high cost and easy decomposition under photocatalytic conditions.…”

Directly Photoexcited Oxides for Photoelectrochemical Water Splitting

“…If this is not the case, the current should be measuredb oth in the dark (j dark ) and under illumination (j light )i nachronoamperometric (current vs. time at constant)e xperiment,a nd j ph is defined as j j light Àj dark j .O ne can expect the onset wavelength (l onset )t ob e closely relatedt ot he E G of the semiconductor;i deally, l onset should be defined as shown in Equations (19) or (20). An additional precaution should be that there is virtually no dark currenta tE PE ,w here IPCE is measured.…”

Beyond Solar Fuels: Renewable Energy‐Driven Chemistry

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Therefore, the term "solar" is considered in its broader meaningo fR E, andt hus is not limitedt ot he directu se of solar radiation. Most such studies have focusedo nt he production of H 2 by water splitting, but growingi nterestconcerns the conversion of CO 2 ,e ven thoughi ti so ften focusedo ns imple two-electron reductions( to CO or formic acid).…”