P-Induced In Situ Construction of ZnCoMOF@CoP-5 S-Scheme Heterojunctions for Enhanced Photocatalytic H₂ Evolution

Abstract

In view of the fact that the exposed catalytic active sites of single-metal MOFs cannot satisfy the efficient progress of the catalytic reaction, here we constructed a star-shaped bimetallic ZnCoMOF by introducing a Zn source by the partial ion exchange method and coprecipitation method. By controlling the quality of sodium hypophosphite, ZnCoMOF was subjected to different degrees of phosphating to optimize the experimental conditions. The introduction of the more electronegative P can attract more H + to participate in the reduction reaction. The ZnCoMOF@CoP-5 S-scheme heterojunction was constructed in situ by generating CoP on the surface of ZnCoMOF under a PH 3 reducing atmosphere, which exhibited excellent H 2 evolution performance. This unique heterojunction effectively promotes the separation and transfer of e − −h + pairs, ensuring a strong redox capability. The best hydrogen-evolution performance of ZnCoMOF@CoP-5 under the EY sensitization system reaches 16 958 μmol h −1 g −1 , which has significant advantages over the same type of materials and similar photocatalytic hydrogen-evolution work. Finally, the photocatalytic mechanism was demonstrated by an in situ XPS technique. Our work provides important ideas for the research of bimetallic MOFs in the field of photocatalytic hydrogen evolution.

NiAl-LDH-Modified Core–Shell Rod-like ZnO@ZnS Heterostructures for Enhanced Photocatalytic Hydrogen Precipitation

“…The heterojunction structure of the material could effectively prevent the electron–hole complex and improve the catalytic performance. Photogenerated holes were captured by water molecules to form highly oxidizing hydroxyl radicals (·OH), which oxidize sacrificial molecules (methanol) to CO 2 and H 2 O, and electrons were captured by H + , leading to the production of H 2 . − …”

Metal–organic framework-based S-scheme heterojunction photocatalysts

“…7g). 86 Carbon nitride (g-C 3 N 4 ) is a fascinating metal-free conjugated polymer and one of the most widely studied semiconductors in various fields. [88][89][90][91] Recently, S-scheme heterojunctions prepared by the hybridization of g-C 3 N 4 with MOFs have also been reported.…”

“…121,122 Recently, MOF-based S-scheme heterojunctions have been applied in PHER with considerable success. 84,86,112 For instance, Jin et al prepared a Co 3 S 4 /Mo 2 S 3 S-scheme heterojunction for PHER via a stepwise hydrothermal method using ZIF-67 as the template (Fig. 12a).…”

“…The abundant surface chemistry of MOFs endows them with great potential for hybridization with other functional materials toward S-scheme heterojunctions. 35 Various non-MOF semiconductors such as metal oxides, 40,45,80 metal sulfides, 81–84 metal phosphides, 85,86 and carbon-based composites 45,64,87 have been involved in synthetic routes including solvothermal treatment and the impregnation method. For example, Tang et al reported a novel CoFe 2 O 4 /iron-based MOF (MIL-101, (MIL = Material Institute Lavoisier)) S-scheme heterojunction photocatalyst by a simple solvothermal method with CoFe 2 O 4 nanoparticles distributed on the surface of MIL-101(Fe) octahedra (Fig.…”

Graphdiyne (CnH2n−2) coupled with ZnCo-MOF double S-scheme heterojunction forms an efficient electron transport layer and its characterizationvia in situXPS

“…The literature presents information about the photocatalysis process of hydrogen production and graphdiyne can be applied for the development of photocatalytic hydrogen production. [19][20][21]42 Previous studies have shown that graphdiyne is a semiconductor material with highly nanoscale macropores, narrow band gap and high electron-hole mobility. Accordingly, the structure and performance of graphdiyne fully meet the requirements of photocatalytic hydrogen production materials, but it also has the disadvantages of fast photogenerated carrier recombination, and thus reducing its high photogenerated carrier recombination rate is an important problem.…”