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• CdS/KPW/meso-g-C 3 N 4 tandem heterojunction is fabricated for the first time. • It has good light response and narrow band gap. • It exhibits excellent visible light photocatalytic activity. • It can be due to the synergy between the Z-scheme and type-II heterojunction. • The tandem heterojunction favors the spatial charge carrier separation greatly. It is known that fabrication of tandem heterojunctions between different types of heterojunctions can promote the charge separation. Herein, novel cadmium sulfide quantum dots (CdS QDs)/dodecahedral phosphotungstic acid potassium K 3 PW 12 O 40 (KPW)/oxygen-doped mesoporous graphite carbon nitride (meso-g-C 3 N 4) nanosheets tandem heterojunctions are prepared by the hydrothermal method combined with direct template calcination and in-situ chemical sedimentation strategy. The results show that tandem heterojunctions formed by the Z-Scheme heterojunction between CdS QDs and KPW and the type-II heterojunction between CdS QDs and meso-g-C 3 N 4 can extend the optical response into visible light region. Importantly, under visible light irradiation, photocatalytic hydrogen production rate and photocatalytic Cr6+ removal rate over CdS/KPW/meso-g-C 3 N 4 is higher than that of KPW and CdS/KPW. This remarkable photocatalytic performance is due to the effective charge separation and transfer of the special tandem heterojunction structure. This novel tandem heterojunction will offer new insights for fabricating other high-performance photocatalytic systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu 2-x S/Fe-POMs/AgVO 3 dual Z-scheme heterojunction is fabricated. • It has wide spectrum response and photothermal effect. • It shows excellent photocatalytic-Fenton degradation performance. • It is due to synergy of SPR effect, photo-Fenton, and dual Z-scheme heterojunction. • Hollow structure has multiple light reflection paths and light collection capability. The assembly photocatalyst with rational design of nanostructure can effectually inhibit the rapid charge recombination and improve the photocatalytic performance. Herein, a hollow cubic Cu 2-x S/Fe-polyoxometalate/AgVO 3 (Cu 2-x S/Fe-POMs/AgVO 3) dual Z-scheme heterojunction superstructure is constructed on the surface of a hollow cubic Cu 2-x S with a clear structure by continuous growth deposition. The hollow cube structure can promote the utilization of light through the refraction and reflection of light in the cavity. Fe-POMs act as the linker between Cu 2-x S and AgVO 3 , providing adequate active sites. In addition, due to the surface plasmon resonance effect of Cu 2-x S, Cu 2-x S/Fe-POMs/AgVO 3 has an obvious photothermal effect, which extends the photoresponse to near-infrared region. The hollow cubic Cu 2-x S/Fe-POMs/AgVO 3 photocatalyst has excellent photocatalytic-Fenton degradation rate of 98.6 % for bisphenol A within 150 min due to the formation of dual Z-scheme heterostructures benefiting spatial charge separation. This work provides new insights for fabricating superstructure photocatalyst with high-performance and broad-spectrum response. [ABSTRACT FROM AUTHOR]

[Display omitted] A hollow core–shell potassium phosphomolybdate (KMoP)@cadmium sulfide (CdS)@bismuth sulfide (Bi 2 S 3) Z-scheme tandem heterojunction is fabricated by a simple hydrothermal strategy and kept in a water bath to continue the reaction. At the same time, the ternary structure combined Keggin-type polyoxometalate with two photosensitive sulfide semiconductors to form a stable hollow core–shell heterojunction. KMoP@CdS@Bi 2 S 3 with a narrow band gap of ∼ 1.2 eV also has excellent photothermal performance, which may further promote photocatalytic efficiency. The hollow core–shell KMoP@CdS@Bi 2 S 3 tandem heterojunction shows excellent H 2 production performance, CrVI reduction ability and photocatalytic degradation performance of highly toxic tetracycline (TC). Under visible light irradiation, the photocatalytic H 2 generation rate of the KMoP@CdS@Bi 2 S 3 tandem heterojunction reaches 831 μmol h−1, which is 103 times higher than that of pristine KMoP. The photocatalytic reduction efficiency of CrVI and degradation efficiency of TC are as high as 95.5 and 97.51%, ∼4 times higher than that of KMoP. The boosted photocatalytic performance can be ascribed to the formation of core–shell Z-scheme tandem heterojunctions favoring spatial charge separation and the narrow band gap, which extends the photoresponse to visible light/NIR regions. When TC and CrVI exist at the same time, the reduction efficiency of CrVI can be as high as 99.64% because the intermediate of TC degradation can promote the reduction of CrVI. In addition, the photocatalytic performance of the KMoP@CdS@Bi 2 S 3 heterojunction remains nearly constant after 4 recycles, which indicates high stability. The design strategy may provide new insights for preparing other high-performance core–shell tandem heterojunction photocatalysts for solar energy conversion. [ABSTRACT FROM AUTHOR]

Phosphorus-doping CdS@NiFe layered double hydroxide Z-Scheme heterojunctions are fabricated by calculations-hydrothermal method and show excellent visible-light photocatalytic activity, which can be attributed to the synergistic effect of photocatalysis and P-doping favoring sunlight harvesting and the effective spatial charge separation. [Display omitted] • P-doped CdS@NiFe-LDH Z-scheme heterojunction is prepared. • The P doping causes a change in the Fermi energy level of CdS. • Photogenerated charge is transferred in porous core–shell Z-scheme heterostructure. • It exhibits significantly improved visible light photocatalytic performance. A novel P-doping CdS nanorods@NiFe layered double hydroxide (LDH) Z-scheme photocatalyst (P-CdS@NiFe-LDH) is synthesized through hydrothermal and calcination strategies. Phosphorus doping could form a new Fermi level and reduce the intermediate band gap, thereby prolonging the lifetime of photo-generated electron carriers. The well-designed core–shell nanostructure is conducive to the rapid transfer of carriers. The formation of Z-scheme heterojunction can provide a higher redox potential and reduce the photo-corrosion phenomenon of CdS. The prepared 20% wt P-CdS@NiFe-LDH sample exhibits the highest hydrogen generation rate, which is about 39 times higher than that of the pristine CdS sample. In addition, the degradation rate of P-CdS@NiFe-LDH photocatalyst on bisphenol A is about 98% within 160 min irradiation. With the addition of H 2 O 2 , the photocatalytic degradation performance can be improved significantly due to the photo-Fenton reaction. The excellent catalytic performance can be attributed to the synergistic effect of P-doping and Z-scheme heterojunction extending the photoresponse and promoting spatial charge separation. This research provides a new perspective for the design and synthesis of other Z-scheme heterojunction structure photocatalysts. [ABSTRACT FROM AUTHOR]

• Novel ternary α-Fe 2 O 3 /defective MoS 2 /Ag Z-scheme heterojunction fabricated for the first time. • Photo-response range extended from UV–vis to infrared light region. • Excellent photo-Fenton catalytic performance in degrading organic pollutants. • Synergistic effect of Z-scheme structure, surface defects and surface plasmon resonance. Hollow Polyhedral superstructures can capture light effectively and have adjustable composite composition, which is useful for constructing Z-scheme systems. Here, rational design of hollow flower-like polyhedral α-Fe 2 O 3 /defective MoS 2 /Ag Z-Scheme heterojunctions is described, using polyhedral α-Fe 2 O 3 as the template and via a one-pot hydrothermal and postdeposition strategy. The hollow flower-like polyhedral heterojunctions utilize multiple reflections of light in the hollow structure to achieve enhanced photocatalytic activity. Defective MoS 2 acts as a link between α-Fe 2 O 3 and Ag nanoparticles, providing a great deal of active sites and broadening the photoresponse region. Because of the enhancement of light absorption and surface plasma resonance of Ag, α-Fe 2 O 3 /defective MoS 2 /Ag has significant photothermal effect. The photogenerated carriers can be effectively separated by the construction of a Z-scheme system. Importantly, photocatalytic-Fenton degradation of 2,4-dichlorophenol and salicylic acid over hollow flower-like polyhedral α-Fe 2 O 3 /defective MoS 2 /Ag is higher than that of α-Fe 2 O 3 and α-Fe 2 O 3 /defective MoS 2. [ABSTRACT FROM AUTHOR]