A silver-inserted zinc rhodium oxide and bismuth vanadium oxide heterojunction photocatalyst for overall pure-water splitting under red light

Abstract

We have prepared a solid-state heterojunction photocatalyst, in which zinc rhodium oxide (ZnRh2O4) and bismuth vanadium oxide (Bi4V2O11) as hydrogen (H2) and oxygen (O2) evolution photocatalysts, respectively, were connected with silver (Ag, ZnRh2O4/Ag/Bi4V2O11).

Selective loading of platinum or silver cocatalyst onto a hydrogen-evolution photocatalyst in a silver-mediated all solid-state Z-scheme system for enhanced overall water splitting

“…S2b, S2d, and S2g in ESI-3, † the Ag 3d peaks for the three photocatalysts were deconvoluted by a pair of Ag 3d peaks (Ag 3d 5/2 and Ag 3d 3/2 , with binding energies of 368.6 AE 0.1 eV and 374.6 AE 0.1 eV, respectively), which is attributable to metallic Ag (Ag 0 ). 8,9,13 These results indicate that Ag was inserted as a metallic particle between ZnRh 8,9 In addition, the Ag cocatalyst was also proved to be deposited as the metallic one. In contrast, the Pt 4f peaks for Pt/ZnRh 2 O 4 /Ag/Bi 4 V 2 O 11 were deconvoluted by three pairs of Pt 4f peaks with binding energies of 71.3 eV (Pt 4f 7/2 ) and 74.6 eV (Pt 4f 5/2 ) for metallic Pt (Pt 0 ), 72.3 eV (Pt 4f 7/2 ) and 75.6 eV (Pt 4f 5/2 ) for Pt 2+ , and 73.3 eV (Pt 4f 7/2 ) and 76.6 eV (Pt 4f 5/2 ) for Pt 3+ (Fig.…”

Recent progress in photocatalysts for overall water splitting

“…Moreover, the construction of a solid‐state Z‐scheme system also exhibited the feasibility of improving Bi‐based photocatalysts for water splitting. For example, ZnRh 2 O 4 /Ag/Bi 4 V 2 O 11 was capable of splitting water even under red light irradiation ( λ > 700 nm) …”

“…Bi-containing photocatalysts with relatively narrow bandgaps are active in visible light irradiation. [108][109][110][111][112][113] However, most of them possess low bottom of conduction band, inhibiting hydrogen evolution reaction. 109 Several strategies were employed to solve this issue.…”

“…For example, ZnRh 2 O 4 /Ag/Bi 4 V 2 O 11 was capable of splitting water even under red light irradiation (λ > 700 nm). 109 To summarize, great efforts, including forming solid solutions, reducing to quantum size, introducing other elements, and fabricating a Z-scheme system, were made to tune the band structures of Bi-containing photocatalysts to meet the thermodynamic requirements of water splitting.…”

Nano‐Bi 2 MoO 6 /calcined mussel shell composites with enhanced photocatalytic performance under visible‐light irradiation

“…4b, the HRTEM image, it can be seen that bismuth molybdate is closely connected to calcium bismuthate. This close connection will produce a heterojunction, which will improve the charge in two kinds of transfer between the semiconductors and inhibit the photogenerated electrons and photo hole load [31][32][33], so as to enhance the quantum efficiency of photocatalyst among them. During the hydrothermal synthesis, on the surface of CMS, calcium bismuthate may form a thin layer of CaBi 2 O 4 , which belongs to the monoclinic system, space group C2/c, a = 16.613, b = 11.590, c = 13.994.…”