Enhanced photocatalytic hydrogen evolution from water splitting by Z‐scheme CdS / BiFeO ₃ heterojunction without using sacrificial agent

Abstract

Summary Cadmium sulfide (CdS) is one of the most famous photocatalyst for water splitting because of relevant band edge position. But it has disadvantage such as recombination of charge carrier and photocorrosion in pure water that sacrificial materials must be used to fix it. On the other hand, the use of other photocatalysts alongside it can greatly eliminate these disadvantages. So, in favor of boosting photocatalytic efficiency, it was coupled with BiFeO3 that is a promising visible light active perovskite structure and has ferroelectric properties. The CdS and BiFeO3 powders were synthesized by precipitation and hydrothermal methods, respectively. The pure samples and heterojunctions were investigated by XRD, FESEM, transmission electron microscopy, EDX, UV‐vis, PL, N2 adsorption/desorption isotherms, photocurrent density measurement, electrochemical impedance spectroscopy and Mott‐Schottky analysis to compare the structure, composition, morphology, and optical property before and after modification. The maximum photocatalytic activity, 600.2 μmol/g/h was obtained by heterojunction containing 50 wt% BiFeO3 (CB‐50) from pure water. Also from the experiments results, CB‐50 showed much higher reusability than pure CdS. The enhanced stability and photocatalytic activity of CB‐50 are mainly attributed to charge separation as a result of Z‐scheme charge transfer mechanism as well as the increased light absorption efficiency. In addition to increasing hydrogen production, the ability to use pure water in a closed system without additional materials is other advantage of this photocatalyst.

Effect of Sr and Ti substitutions on optical and photocatalytic properties of Bi1−xSrxFe1−xTixO3 nanomaterials

“…48 The BFO presents a low H 2 yield of ∼0.87 mmol g −1 , similar to reported values obtained in neat BFO systems. 49 On the other hand, the STO system appears to yield an HER of ∼57 mmol g −1 , which is in line with values reported elsewhere. 19,50 Interestingly, the highest electron density achieved in the BFO-xSTO (x = 12.5%) resulted in a considerable increase in the H 2 yield to about 191 mmol g −1 .…”

Visible‐Light‐Driven LaFeO3/CdS Heterojunction Photocatalysts for Photo‐Fenton Degradation of Levofloxacin

“…The narrower band gap enables the material to have a wider visible light absorption range and improve the utilization efficiency of visible light. In addition, the conduction band (E CB ) and valence band (E VB ) values of LFO and CS can be calculated using Equation (S2–S3) [22] …”

“…). [22] The surface elements and their chemical states of LaFeO 3 , CdS and LFO/CS-40 were further studied by X-ray photoelectron spectroscopy (XPS), and exhibited in Figure 4.…”

Visible-light photocatalytic hydrogen production in a narrow-bandgap semiconducting La/Ni-modified KNbO3 ferroelectric and further enhancement via high-field poling

“…By comparison (Fig. 1f), [9][10][11][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] the visible-light PHE rate of the poled semiconducting La/Ni-modied KNbO 3 ferroelectrics was superior to that of most perovskite ferroelectric oxides, such as KNbO 3based, BaTiO 3 -based and PbTiO 3 -based ferroelectric photocatalysts. These results provide a reference for further investigating high-performance ferroelectric-based oxide photocatalytic materials.…”