Strategies for Efficient Charge Separation and Transfer in Artificial Photosynthesis of Solar Fuels

Abstract

Converting sunlight to solar fuels by artificial photosynthesis is an innovative science and technology for renewable energy. Light harvesting, photogenerated charge separation and transfer (CST), and catalytic reactions are the three primary steps in the processes involved in the conversion of solar energy to chemical energy (SE‐CE). Among the processes, CST is the key “energy pump and delivery” step in determining the overall solar‐energy conversion efficiency. Efficient CST is always high priority in designing and assembling artificial photosynthesis systems for solar‐fuel production. This Review not only introduces the fundamental strategies for CST but also the combinatory application of these strategies to five types of the most‐investigated semiconductor‐based artificial photosynthesis systems: particulate, Z‐scheme, hybrid, photoelectrochemical, and photovoltaics‐assisted systems. We show that artificial photosynthesis systems with high SE‐CE efficiency can be rationally designed and constructed through combinatory application of these strategies, setting a promising blueprint for the future of solar fuels.

Pompon Dahlia‐like Cu2O/rGO Nanostructures for Visible Light Photocatalytic H2 Production and 4‐Chlorophenol Degradation

“…Charge carrier separation and hence photocatalytic performance depend on the electronic band structure, band alignment and interfacial contact of photocatalysts . Band energies were investigated by valence band XPS (Figure S4a–c); the VB potential maxima of hierarchical Cu 2 O and the Cu 2 O/rGO nanocomposite were +1.30 and +1.10 eV respectively relative to the Fermi level, and corresponding CB minima edges (derived from the optical band gap and valence band XP spectra) were −1.12 eV and −1.03 eV for Cu 2 O/rGO.…”

“…Charge carrier separation and hence photocatalytic performance depend on the electronic band structure, band alignment and interfacial contact of photocatalysts. [39] Band energies were investigated by valence band XPS ( Figure S4a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 the VB potential maxima of hierarchical Cu 2 O and the Cu 2 O/rGO nanocomposite were + 1.30 and + 1.10 eV respectively relative to the Fermi level, and corresponding CB minima edges (derived from the optical band gap and valence band XP spectra) were À 1.12 eV and À 1.03 eV for Cu 2 O/rGO. The CB minimum is therefore unaffected by formation of the Cu 2 O/rGO heterojunction, albeit more negative than previous reports (e. g. À 0.42 for oxygen-deficient Cu 2 O nanoparticles [40] ), and in both cases much greater than required for photocatalytic hydrogen production from water (À 0.65 eV at pH 7).…”

Regulation of Ferroelectric Polarization to Achieve Efficient Charge Separation and Transfer in Particulate RuO2/BiFeO3 for High Photocatalytic Water Oxidation Activity

“…[ 9,10 ] The strategies for efficient separation and transfer of photogenerated charges have been also well reviewed. [ 11 ]…”

Recent Developments in Graphitic Carbon Nitride Based Hydrogels as Photocatalysts

“…Since then, numerous researchers have focused on developing novel materials for an efficient photocatalytic water‐splitting reaction. Heterogeneous photocatalytic systems containing suspended particles in water or aqueous solution with appropriate sacrificial reagents were identified and developed extensively . In the photocatalytic suspension system, individual particles of powdered samples with a high specific surface area strongly collide with each other, enhancing interparticle electron transfer, thereby improving the photocatalytic activity .…”