Design and Preparation of a CeVO₄/Zn_0.5Cd_0.5S S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution

Abstract

Improving the separation efficiency of photoinduced electron−hole pairs plays a vital role in preparing highperformance photocatalysts. Here, based on the good light corrosion resistance and excellent visible light response of Zn 0.5 Cd 0.5 S, as well as the unique catalytic, optical, and electrical properties of CeVO 4 , we tightly loaded CeVO 4 on Zn 0.5 Cd 0.5 S by physical coupling to overcome its severe photogenic carrier recombination and obtained a highly efficient photocatalytic catalyst for hydrogen evolution. One the one hand, the close coupling of Zn 0.5 Cd 0.5 S and CeVO 4 effectively inhibited the serious aggregation of Zn 0.5 Cd 0.5 S, which is conducive to the generation of active sites. On the other hand, an S-scheme heterojunction at the contact interface of Zn 0.5 Cd 0.5 S and CeVO 4 was successfully built. The formation of the S-scheme heterojunction could consume useless electrons and holes and enable the efficient use of photogenerated electrons to participate in the reaction of reducing water. Finally, the hydrogen yield of Zn 0.5 Cd 0.5 S/CeVO 4 can reach 695.55 μmol in 5 h. Our work provided an idea for the rational design of heterojunction photocatalysts to obtain excellent hydrogen production performance.

Construction of CoP/Cu3P/Ni2P Double S-Scheme Heterojunctions for Improved Photocatalytic Hydrogen Evolution

“…As shown in Figure d,e, the slope of the E -– C 2 curve before the introduction of copper is positive, reflecting its n-type semiconductor properties. In Figure f, it is clear that the composite catalyst has two linear regions in the plot, and it is found that the Fermi energy levels are displaced due to the formation of a double S-scheme heterojunction . As we all know, the position of the Fermi level of a semiconductor can be roughly estimated based on the flat band potential.…”

“…In Figure 9f, it is clear that the composite catalyst has two linear regions in the plot, and it is found that the Fermi energy levels are displaced due to the formation of a double S-scheme heterojunction. 32 As we all know, the position of the Fermi level of a semiconductor can be roughly estimated based on the flat band potential. By actual measurement, the flat band potential and band gap of CoP are −0.36 and 1.91 eV, respectively.…”

“…Recently, a novel S-scheme heterojunction has been proposed by Yu et al and has attracted great attention . The S-scheme heterojunction mainly consists of a reducing semiconductor photocatalyst and an oxidizing semiconductor photocatalyst, achieving the spatial separation of electron–hole pairs and maintaining strong redox ability. − Generally, the effective electron–hole pairs can be retained, while the nonsensical photogenerated carriers are recombined, thereby vastly restraining the recombination of photocatalytic charge carriers in the S-scheme system. − An internal electric field would be formed between the two semiconductors due to the Femi level difference, and the build of the internal electric field further improves the photoexciton transfer and separation efficiency. − Therefore, the rational construction of S-scheme heterojunctions is very important to optimize the photocatalytic hydrogen evolution performance.…”

Fabrication of NiFe‐PBA‐S / ZnCdS form S‐scheme for improved photocatalytic hydrogen evolution

“…Since 1972, when Fujishima and Honda pioneered hydrogen generation using rutile titanium dioxide (TiO 2 ) electrodes, a variety of methodologies have been utilized to research and build effective water separation systems. [7][8][9] Among these, the fabrication of S-scheme heterojunctions is a potential method for the creation of highly effective photocatalysts. 10 Economically, semiconductor materials with favorable photocatalytic characteristics should be synthesized using common elements, making it critical to develop alternatives for precious metals.…”

“…Hydrogen production from solar is widely considered to be among the most viable methods for generating renewable energy. Since 1972, when Fujishima and Honda pioneered hydrogen generation using rutile titanium dioxide (TiO 2 ) electrodes, a variety of methodologies have been utilized to research and build effective water separation systems 7‐9 . Among these, the fabrication of S‐scheme heterojunctions is a potential method for the creation of highly effective photocatalysts 10 .…”