Fabrication of walnut-like BiVO4@Bi2S3 heterojunction for efficient visible photocatalytic reduction of Cr(VI)

Insights into the photocatalytic performance of Bi2O2CO3/BiVO4 heterostructures prepared by one-step hydrothermal method

“…8 Different strategies have been studied to obtain heterostructures such as one-step methods (simultaneous crystallization) [15][16][17][18] and the use of one and/or two preformed particles (heterojunctions formation by attachment). 9,[19][20][21][22][23][24] The growth of BiVO 4 on Bi 2 O 2 CO 3 surface (preformed) under hydrothermal conditions driven by their difference in solubility is a more interesting and efficient approach for the formation of this kind of heterostructure. This is because the formation of the heterojunction is unavoidable, since mandatorily BiVO 4 will grow using the bismuth present on the surface of Bi 2 O 2 CO 3 .…”

One-pot synthesis of peony-like Bi2S3/BiVO4(040) with high photocatalytic activity for glyphosate degradation under visible light irradiation

“…Taking the absolute electronegativity values for Bi, V, S, and O as 4.69, 3.6, 6.22, and 7.54, respectively, the calculated χ values of Bi2S3 and BiVO4 are 5.56 and 6.16 eV, respectively. The calculated VB potential of BiVO4 (EVB = 2.87 eV vs. NHE) is more positive than that of Bi2S3 (EVB = 1.69 eV vs. NHE), while the calculated CB potential of Bi2S3 (EVB = 0.42 eV vs. NHE) is more negative than that of BiVO4 (EVB = 0.45 eV vs. NHE) [29,32]. Therefore, the energy levels of Bi2S3 and BiVO4 are well matched and the Bi2S3/BiVO4 heterojunction could be formed, favoring the separation of photogenerated charge carriers.…”

“…As the visible light absorption capacity of Bi2S3/BiVO4 is better than that of BiVO4, a higher number of electron-hole pairs are generated over Bi2S3/BiVO4. The photogenerated electrons in the CB of Bi2S3 transfer to BiVO4 [29], then react with adsorbed O2 to yield •O2 − , and subsequent redox reactions may occur. The photogenerated holes formed in the VB of BiVO4 react with the adsorbed H2O/OH − ions to produce •OH or directly oxidize glyphosate.…”

“…Considering that the band gap of Bi2S3 is smaller than that of BiVO4 (Eg = 2.4 eV), and that the valence band (VB) potential (EVB) of BiVO4 (EVB = 2.71 eV vs. normal hydrogen electrode, NHE) is more positive than that of Bi2S3 (EVB = 1.42 eV vs. NHE) [28], the energy levels of Bi2S3 and BiVO4 appear to be well matched, so that a heterojunction enabling the efficient separation of photogenerated charge carriers could be formed. The formation of a heterojunction structure between BiVO4 and Bi2S3 has been achieved using Na2S [29,30], thioacetamide [31,32], and L-cysteine [33] as the sulfur source, resulting in enhanced photocatalytic activity due to the retarded recombination of photogenerated carriers.…”

Synthesis of novel α-Fe2O3-Bi2S3-Gr for efficient photocatalytic degradation of environmental pollutants under visible-LED light irradiation

“…Many binary heterojunctions have been tested to overcome these issues, such as α-Fe 2 O 3 -WO3, BiVO 4 -Bi 2 S 3 , α-Fe 2 O 3 -BiOI, α-Fe 2 O 3 -Bi 2 S 3 , Bi 2 S 3 -ZnO and etc. [15,16,20,21,[23][24][25][26][27][28][29][30][31]. Meanwhile, many works showed an improvement of performance in organic contaminant degradation by incorporation of a carbonaceous material into photocatalysts with, both singular or binary metal oxides such as α-Fe 2 O 3 -graphene, Bi 2 S 3 -AC, α-Fe 2 O 3 -CNTs; Bi 2 S 3 -Gr, α-Fe 2 O 3 -WO 3 -graphene, α-Fe 2 O 3 -ZnO-graphene and etc.…”