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[Display omitted] As a renewable green energy, hydrogen has received widespread attention due to its huge potential in solving energy shortages and environment pollution. In this paper, a one-step solvothermal method was applied to grow ultra-thin g-C 3 N 4 (UCN) nanosheets and NiS nanoparticles on the surface of ZnIn 2 S 4 (ZIS). A ternary NiS/ZnIn 2 S 4 /ultra-thin-g-C 3 N 4 composite material with dual high-speed charge transfer channels was constructed for the advancement of the photocatalytic H 2 generation. The optimal ternary catalyst 1.5wt.%NiS/ZnIn 2 S 4 /ultra-thin-g-C 3 N 4 (NiS/ZIS/UCN) achieved a H 2 evolution yield reached to 5.02 mmolg−1h−1, which was 5.23 times superior than that of pristine ZnIn 2 S 4 (0.96 mmolg−1h−1) and even outperform than that of the best precious metal modified 3.0 wt%Pt/ZnIn 2 S 4 (4.08 mmolg−1h−1). The AQY at 420 nm could be achieved as high as 30.5%. The increased photocatalytic performance of NiS/ZIS/UCN could be ascribed to the type-I heterojunctions between intimated ZIS and UCN. In addition, NiS co-catalyst with large quantity of H 2 evolution sites, could result in efficient photo-induced charges separation and migration. Furthermore, the NiS/ZIS/UCN composite exhibited excellent H 2 evolution stability and recyclability. This work would also offer a reference for the design and synthesis of ternary co-catalyst with heterojunction composite for green energy conversion. [ABSTRACT FROM AUTHOR]

Promoting the separation of photogenerated electron–hole pairs and enhancing the charge carrier transfer are critical in photocatalysis. In our work, a ball-flower-like NiS/Zn3In2S6/g-C3N4 photocatalyst fabricated by a hydrothermal method exhibited superior performance for photocatalytic water splitting. The optimized 2.0% NiS/Zn3In2S6/g-C3N4 rivaled noble metal based Pt/g-C3N4 and showed an apparent quantum efficiency (AQE) of 24.3% at 420 nm, with a H2 yield of 4.135 mmol g−1 h−1, which was 30.4 and 9.51 times that of pure g-C3N4 and binary Zn3In2S6/g-C3N4 composites, respectively. The experimental and characterization results suggested that the heterojunction formed between Zn3In2S6/g-C3N4 and the decorating NiS co-catalyst cooperatively suppressed the electron–hole recombination and facilitated the charge carrier transfer, thus resulting in significant improvement of the H2 evolution performance. Moreover, the increased specific surface area and the enhanced visible-light absorption also contributed to superior water splitting performance. The prepared ternary catalytic system with the heterojunction and non-noble metal co-catalyst has great potential as an alternative to noble metals for achieving cost-efficient water splitting systems. [ABSTRACT FROM AUTHOR]

Facilitating the separation of photoexcited electron-hole pairs and enhancing the migration of photogenerated carriers are essential in photocatalytic reaction. CoS/g-C 3 N 4 /NiS ternary photocatalyst was prepared by hydrothermal and physical stirring methods. The optimized ternary composite achieved a hydrogen yield of 1.93 mmol g−1 h−1, 12.8 times that of bare g-C 3 N 4 , with an AQE of 16.4% at 420 nm. The enhanced photocatalytic activity of CoS/g-C 3 N 4 /NiS was mainly ascribed to the synergistic interaction between the Z-scheme heterojunction constructed by CoS and g-C 3 N 4 and the NiS co-catalyst featuring a large amount of hydrogen precipitation sites, which realized the efficient separation and migration of photogenerated carriers. In addition, the CoS/g-C 3 N 4 /NiS heterojunction-co-catalyst system exhibited excellent photocatalytic stability and recyclability. • CoS/g-C 3 N 4 /NiS ternary photocatalyst was prepared by hydrothermal and physical stirring methods. • A large amount of hydrogen precipitation sites are available on CoS/g-C 3 N 4 /NiS ternary photocatalyst. • The Z-scheme heterojunction combined with the co-catalyst promoted the separation and migration of photogenerated carriers. [ABSTRACT FROM AUTHOR]

Graphite carbon nitride (g‐C3N4), as a non‐metallic photocatalyst, possesses special band structure, excellent stability and unique surface properties, which has become a focus of attention for photocatalytic application. However, pure g‐C3N4 is subject to the limit of visible light response, small specific surface area and rapid recombination of photogenerated carriers, which leads to its low photocatalytic efficiency. Due to the unique electronic structure, various quantum dots (QDs) can be applied to modify g‐C3N4 to improve the photocatalytic activity. Thus, we highlight these QDs modified g‐C3N4‐based composites by emphasizing their synthesis, their physicochemical properties as well as their photocatalytic applications in CO2 reduction, hydrogen production and pollutants degradation in this review. At last, critical summaries and some perspectives on the challenges and directions in this research field are also presented. [ABSTRACT FROM AUTHOR]

• Novel flower spherical-like Bi-Bi 7 O 9 I 3 /Ag-AgI S-scheme heterojunction was synthesized. • Dual plasmons (Bi, Ag) enhance the visible light absorption and photothermal effect. • The synergistic role of S-scheme heterojunction, SPR effect and photothermal effect contributed to the excellent phenol photodegradation and removal activity. • Theoretical calculation expressed Fermi energy levels and work function. The flower spherical-like S-scheme Bi 7 O 9 I 3 /AgI heterostructure was successfully fabricated through hydrothermal as well as calcination reduction method. The Ag and Bi nanoparticles generated during calcination reduction process are tightly fixed on surface of Bi 7 O 9 I 3 and AgI, severally, which was distinctly beneficial to the charge transfer. On account of the enhanced light absorption and surface plasma resonance of Ag and Bi, Bi-Bi 7 O 9 I 3 /Ag-AgI possessed conspicuous photothermal effect. The results show that Bi-Bi 7 O 9 I 3 /Ag-AgI possessesed the optimal photodegradation efficiency and TOC removal rate of phenol, which are 100% and 95.38% within 80 min and 120 min. The light-induced carriers could be efficaciously separated by establishing an S-scheme photocatalytic system. A possible photocatalytic degradation mechanism of the as-constructed samples was investigated by free radical capture experiment as well as EPR technique. In addition, the photocatalyst exhibited the high stability. This work will supply a new perspective with the synthesis of novel S-scheme heterostructure. [ABSTRACT FROM AUTHOR]

The development of photocatalytic technology can not only reduce CO 2 emissions, but also realize the effective utilization of solar energy, thus alleviating the global energy crisis. In this work, BiOIO 3 /g-C 3 N 4 Z-scheme heterojunction modified by Ti 3 C 2 nanosheets was designed and fabricated through hydrothermal method and electrostatic self-assembly strategy. The g-C 3 N 4 /BiOIO 3 /Ti 3 C 2 (4 wt%) photocatalytic system exhibited the optimal photocatalytic efficiency, reaching 5.88 and 1.55 μ mol/g/h for CO and CH 4 , respectively, and the CO production rate was 6.6 folds as high as that of bare g-C 3 N 4. Various characterization techniques were utilized to research the physicochemical properties of as-prepared photocatalysts. Z-scheme heterojunction formed between g-C 3 N 4 and BiOIO 3 and the decorating of 2D Ti 3 C 2 co-catalyst were responsible for the boosted photocatalytic behavior. Z-scheme heterojunction could prevent the recombination of charge carriers, the co-catalyst Ti 3 C 2 acted as electron sink could achieve quick shift of photo-induced electrons and supply numerous active sites for photocatalytic reaction. [Display omitted] [ABSTRACT FROM AUTHOR]

S-scheme heterostructure can facilitate the separation of carriers while maintain outstanding redox capacity. A series of ternary Bi 7 O 9 I 3 /g-C 3 N 4 /Bi 3 O 4 Cl photocatalytic system was triumphantly synthesized via oil bath method in this work and used in photocatalytic degradation of phenol. The optimal TOC removal rate reached up to 93.57% under illumination for 160 min, which was slightly lower than phenol photodegradation (about 100%, 100 min). Correspondingly, the apparent rate constants for the decay of phenol are determined to be 0.0211 min−1. The experiment of free radical capture indicated that ·OH and ·O 2 − were the major oxidizing substances to degrade phenol. The products of phenol photodegradation were identified by high performance liquid chromatography (HPLC) and a possible degradation pathway was proposed. The characterization analysis and density functional theory (DFT) calculations demonstrated that dual S-scheme charge migration was generated at the interface of Bi 7 O 9 I 3 , g-C 3 N 4 and Bi 3 O 4 Cl, contributing to an efficient separation of light-excited carriers. In the field of environmental remediation, the discovery of this work could open up promising vistas for designing bismuth-based ternary heterostructures with application potentiality. [Display omitted] • Flower spherical-like Bi 7 O 9 I 3 /g-C 3 N 4 /Bi 3 O 4 Cl was synthesized by oil bath method. • Bi 7 O 9 I 3 /g-C 3 N 4 /Bi 3 O 4 Cl heterojunction with enhanced phenol degradation activity. • ·OH and ·O 2 − were the major oxidizing substances to degrade phenol. • Bi 7 O 9 I 3 /g-C 3 N 4 /Bi 3 O 4 Cl composite followed dual S-scheme heterojunction photocatalytic mechanism. • Dual S-scheme Bi 7 O 9 I 3 /g-C 3 N 4 /Bi 3 O 4 Cl heterojunction contribute to an efficient separation of light-excited carriers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Direct Z-scheme FeWO 4 /NiAl-LDH heterostructure was fabricated. • The 10%FWLDH possessed the optimal photocatalytic CO yield. • The effective separation of the light-induced e-/h+ pairs was available on FWLDH composite. In recent years, photocatalytic reduction of carbon dioxide technology has been considered as an effective approach to moderate the energy crisis. In order to achieve efficient reduction of CO 2 , direct Z-scheme heterostructure composed of NiAl-LDH flower-like sphere and FeWO 4 nanoflakes (FWLDH) were obtained through a facile hydrothermal strategy. The prepared FWLDH photocatalysts revealed outstanding performance for CO 2 photoreduction to CO under the irradiation of visible light. The 10%FWLDH possessed the optimal photocatalytic CO yield (5 μmol· g−1·h−1), reaching up to 2.4 folds higher than that of pristine LDH (2.1 μmol·g−1·h−1). In addition, the CO selectivity was more than 93% over hydrogen evolution from the side reaction of water reduction. Finally, EPR characterization indicated that the electron transfer mechanism of FWLDH catalyst conformed to the Z-scheme pattern. The effective separation of the light-induced electron-hole pairs and the enhancement of the photoelectron reduction ability at the NiAl-LDH conduction band were the reasons for the prominent improvement of the photocatalytic performance of NiAl-LDH. This research could provide a novel perspective for designing photocatalyst with high efficiency for CO 2 photoreduction. [ABSTRACT FROM AUTHOR]

• The development of dyes degradation using currently developed MoS 2 -based materials is summarized. • The properties, structure and preparation methods of MoS 2 are briefly discussed. • Different active species and the possible degradation pathways for dyes degradation are also discussed. Photocatalysis technology has been considered as the greenest route for degrading and mineralizing organic pollutants due to its high efficiency, economy and environment-friendliness. Two-dimensional transition metal dichalcogenides represented by molybdenum disulfide (MoS 2) have attracted broad attention because of their large specific surface area and adjustable interlayer spacing. In recent years, it has shown great application potential in the photocatalytic degradation field. In this review, we mainly introduce the development of dyes degradation using currently developed MoS 2 -based materials. The properties, structure and preparation methods of MoS 2 are briefly discussed in this article. What's more, the progress in improving the degradation efficiency of MoS 2 -based photocatalysts is also discussed. Moreover, different active species and the possible degradation pathways for dyes degradation are also discussed in this context. The results show that MoS 2 -based materials have a broad application prospect in photocatalytic degradation of environmental pollutants. [ABSTRACT FROM AUTHOR]