Molecular Catalyst Immobilized Photocathodes for Water/Proton and Carbon Dioxide Reduction

Abstract

As one of the components in a tandem photoelectrochemical cell for solar-fuel production, the photocathode carries out the reduction reaction to convert solar light and the corresponding substrate (e.g., proton and CO2) into target fuels. Immobilizing molecular catalysts onto the photocathode is a promising strategy to enhance the interfacial electron/hole-transfer process and to improve the stability of the catalysts. Furthermore, the molecular catalysts are beneficial in improving the selectivity of the reduction reaction, particularly for CO2 reduction. On the photocathode, the binding mode of the catalysts and the arrangement between the photosensitizer and the catalyst also play crucial roles in the performance and stability of the final device. How to firmly and effectively immobilize the catalyst on the photoelectrode is now becoming a scientific question. Recent publications on molecular catalyst immobilized photocathodes are therefore surveyed.

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.…”

Semiconductor‐Based Photoelectrochemical Conversion of Carbon Dioxide: Stepping Towards Artificial Photosynthesis

“…Immobilization of a suitable metal complex through a polymer or electropolymerization on a semiconductor photocathode is promising to enhance charge transfer and the selectivity of PEC CO 2 reduction. Because there are many reviews focused on metal complexes in carbon dioxide reduction, only very recent publications related to assembly on semiconductors are summarized herein (Table ).…”

Nanostructured p-Type Semiconductor Electrodes and Photoelectrochemistry of Their Reduction Processes

“…When realized through photoelectrolysis, both H2 fuel generation [20] and CO2 transformation [21] constitute redox reduction processes which occur at the photoactive cathodes exploiting the charge separation primarily induced by light absorption [22,23]. For this reason it will be shown in the last two sections of this contribution how important is the design of cathodes with photoelectrocatalytic properties, and how challenging is the eventual improvement of their photoelectrochemical performance via electrode and/or dye-sensitizer modification [24] to render feasible the production of energy by the renewable source of solar light.…”