Urchin-like TiO₂/CdS Nanoparticles Forming an S-scheme Heterojunction for Photocatalytic Hydrogen Production and CO₂ Reduction

S-Scheme Heterojunction Photocatalysts for CO2 Reduction

“…Under light irradiation, the surface potential of point A decreased, while that of point B increased (Figure 4b,c), and the change in surface potential fully revealed the transfer of photogenerated electrons from OP to RP [76]. The above two techniques provide direct evidence for the S-scheme charge transfer mechanism, while EPR is an indirect method to verify the S-scheme charge transfer mechanism [77,78] The parameters, such as work functions and differential charge density, can b obtained from DFT calculation (Figure 5a,b). The interfacial electron transfer between R and OP can be visually reflected by charge density differences [80].…”

Fluorinated-TiO2/Mn0.2Cd0.8S S-Scheme Heterojunction with Rich Sulfur Vacancies for Photocatalytic Hydrogen Production

“…However, the result shows that the hydrogen production property of F-TiO 2 /MCS was significantly improved when the F-TiO 2 was compounded with MCS. Compared to MCS, the F-TiO 2 /MCS composite exhibits enhanced photocatalytic H 2 production activity, which can be attributed to the construction of an S-scheme heterojunction, promoting photogenerated electron–hole pair separation, and sulfur vacancies can enrich H 2 adsorption active centers and capture photogenerated electrons, changing the electron distribution on the heterojunction surface . Furthermore, when the platinum cocatalyst was not added, hydrogen-producing performance was lower than that when added (Figure b).…”

“…To date, several methods have been employed to enhance the photocatalytic activity of MCS, such as cocatalyst addition, heterojunction structure construction, loading precious metals (Ag, Pt), and defect engineering. , Among them, defect engineering is one of the most effective means of improving the surface activity centers of catalysts. Many defective photocatalytic materials have been manufactured by researchers, including oxygen-containing defective In 2 O 3 and TiO 2 , sulfur-containing defective Zn 0.5 Cd 0.5 S, and nitrogen-containing defective C 3 N 4 . − The defect sites not only efficiently adsorb hydrogen molecules but also additionally capture photogenerated electrons in the conduction band, altering the local electron distribution of the catalyst. Although the solid solution material itself possesses defects that lead to an abundance of adsorption active sites in the photocatalytic hydrogen generation process, how to properly promote the separation of photogenerated electron–hole pairs is a significant challenge: this is the exact property of an S-scheme heterojunction. − Nevertheless, a single semiconductor is unable to satisfy the requirements for effective charge separation and transfer as well as wide light absorption.…”

Theoretical Prediction and Synthesis of Nonmetal-Doped Anatase TiO2 (101) for Boosting Photocatalytic Hydrogen Evolution Reaction

“…Photocatalysis is a promising technology for the production of clean energy using sunlight-excited semiconductor photocatalysts. − Hydrogen is the world’s cleanest energy source. − The high density and low pollution characteristics of hydrogen energy have made hydrogen evolution and application technologies a focus of attention in the 21st century. In the background of global energy demand and the global carbon cycle, researchers have explored a large number of photocatalysts for hydrogen evolution. − However, most photocatalysts are prone to photogenerated carrier recombination under light excitation, , resulting in inadequate photocatalytic efficiency.…”