Regulation of the photogenerated carrier transfer process during photoelectrochemical water splitting: A review

Enhancing the Visible Light Photoelectrochemical Water Splitting of TiO2 Photoanode via a p–n Heterojunction and the Plasmonic Effect

“…These together could result in a highly enhanced PEC hydrogen production efficiency for water splitting. Figure 4b shows the schematic diagram of the mechanism occurring under >420 nm visible light irradiation, where the energy alignment 22,52 was done according to the experimentally obtained energy levels from the absorption spectra (Figures 4a,b and S3) and ultraviolet photoelectron spectroscopy (UPS, Figure S5) characterizations, which are summarized in Table S2 in the Supporting Information, and consistent with the reported work function, ionization energy, and band gap of TiO 2 , CuInS 2 , and Cu. 12,25,42,43,53 When the TiO 2 /CuInS 2 /Cu photoanode is illuminated by >420 nm visible light, a large number of collective SPR hot electrons are induced on the surface of Cu and occupy the energy level of Cu above E F and then transfer to the conduction band (CB) of nearby CuInS 2 .…”

“…Relatively, the p–n heterojunction can make the migration of photogenerated carriers meet the requirements of PEC under the driving force of the built-in electric field, i.e. , photogenerated electrons directionally transfer from the conduction band (CB) of a p-type semiconductor to that of an n-type semiconductor, while the photogenerated holes transfer in the reverse direction, participating in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. , Then, decorating the n-type TiO 2 photoelectrocatalyst with a suitable p-type semiconductor could be a promising route for catalyst designing. CuInS 2 , as a p-type ternary metal sulfide of group I-III-VI 2 , has a direct band gap of 1.5 eV, high visible light absorption coefficient, good chemical stability, low toxicity, and photocathodic protection property .…”

2023 roadmap on photocatalytic water splitting

“…The need for solar hydrogen generation has risen in recent years. One of the most promising techniques in the conservation of solar energy is PC water splitting into hydrogen [44], which is cost-effective and environmentally benign [45,46]. The factors such as bandgap energy, Fermi energy level, charge-carrier recombination rate, crystal structure, movement of free carriers, surface charge, and other surface properties play an important role in the PC process.…”

Photoelectrochemical water splitting process using titanium dioxide photocatalyst: A brief overview

“…As a result, developing a continuous, renewable, and clean energy supply to protect the environment by reducing pollution emissions is the most pressing concern for human civilization. H2 is now widely regarded as an ideal future energy carrier [1], [2]. The energy yield of H2 is approximate 122 kJ/g which this provided energy is larger than the energy provided by conventional hydrocarbon fossil fuels combustion [3].…”

“…Large varieties of semiconductor (metal oxide) materials are used as photocatalysts in the PEC water splitting process. Photocatalysts activated by solar irradiation produce photogenerated electrons and holes, and they will react with water to generate H2 and O2 effectively [1], [9].…”