Hierarchical Layered WS2 /Graphene-Modified CdS Nanorods for Efficient Photocatalytic Hydrogen Evolution

Heterostructured WS2 -MoS2 Ultrathin Nanosheets Integrated on CdS Nanorods to Promote Charge Separation and Migration and Improve Solar-Driven Photocatalytic Hydrogen Evolution

Solar-driven photocatalytic hydrogen evolution is important to bring solar-energy-to-fuel energy-conversion processes to reality. However, there is a lack of highly efficient, stable, and non-precious photocatalysts, and catalysts not designed completely with expensive noble metals have remained elusive, which hampers their large-scale industrial application. Herein, for the first time, a highly efficient and stable noble-metal-free CdS/WS₂ -MoS₂ nanocomposite was designed through a facile hydrothermal approach. When assessed as a photocatalyst for water splitting, the CdS/WS₂ -MoS₂ nanostructures exhibited remarkable photocatalytic hydrogen-evolution performance and impressive durability. An excellent hydrogen evolution rate of 209.79 mmol g^-1  h^-1 was achieved under simulated sunlight irradiation, which is higher than the values for CdS/MoS₂ (123.31 mmol g^-1  h^-1 ) and CdS/WS₂ nanostructures (169.82 mmol g^-1  h^-1 ) and the expensive CdS/Pt benchmark catalyst (34.98 mmol g^-1  h^-1 ). The apparent quantum yield reached 51.4 % at λ=425 nm in 5 h. Furthermore, the obtained hydrogen evolution rate was better than those of several noble-metal-free catalysts reported previously. The observed high rate of hydrogen evolution and remarkable stability may be a result of the ultrafast separation of photogenerated charge carriers and transport between the CdS nanorods and the WS₂ -MoS₂ nanosheets, which thus increases the number of electrons involved in hydrogen production. The proposed designed strategy is believed to potentially open a door to the design of advanced noble-metal-free photocatalytic materials for efficient solar-driven hydrogen production.

2D Transition Metal Dichalcogenides and Graphene-Based Ternary Composites for Photocatalytic Hydrogen Evolution and Pollutants Degradation

Photocatalysis have attracted great attention due to their useful applications for sustainable hydrogen evolution and pollutants degradation. Transition metal dichalcogenides (TMDs) such as MoS₂ and WS₂ have exhibited great potential as cocatalysts to increase the photo-activity of some semiconductors. By combination with graphene (GR), enhanced cocatalysts of TMD/GR hybrids could be synthesized. GR here can act as a conductive electron channel for the transport of the photogenerated electrons, while the TMDs nanosheets in the hybrids can collect electrons and act as active sites for photocatalytic reactions. This mini review will focus on the application of TMD/GR hybrids as cocatalysts for semiconductors in photocatalytic reactions, by which we hope to provide enriched information of TMD/GR as a platform to develop more efficient photocatalysts for solar energy utilization.

P, Thakur A, Basu S. Enhanced photocatalytic water splitting by gold carbon dot core shell nanocatalyst under visible/sunlight

Hydrogen production from water using photocatalysts under sunlight still remains a huge challenge.

One-step syntheses of MoS2/graphitic carbon composites with enhanced photocatalytic activity under visible light irradiation

MoS₂/GC composites were synthesized with sodium alginate as carbon source, and the reason for enhanced photocatalytic activity has been revealed.

Investigating the role of MoS2/reduced graphene oxide as cocatalyst on Cu2O activity in catalytic and photocatalytic reactions

Synergistic effect of MoS₂/rGO as cocatalyst on Cu₂O catalytic and photocatalytic activity.

Confinement effect of monolayer MoS2 quantum dots on conjugated polyimide and promotion of solar-driven photocatalytic hydrogen generation

Monolayer MoS₂ quantum dot (MQD) confined polyimide demonstrates 360% enhancement in hydrogen production compared to Pt/PI under solar light.

Facile synthesis of ZnO/CdS@ZIF-8 core–shell nanocomposites and their applications in photocatalytic degradation of organic dyes

ZnO/CdS@ZIF-8 core–shell nanocomposites were fabricated which exhibited remarkable coherent function for adsorption and photocatalytic degradation of organic pollutants.

Noble-metal-free nickel phosphide modified CdS/C3N4 nanorods for dramatically enhanced photocatalytic hydrogen evolution under visible light irradiation

A highly efficient noble metal free Ni₂P–CdS/g-C₃N₄ composite was constructed based on the concept of combining heterojunction engineering with co-catalyst modification.

Preparation and enhanced photocatalytic hydrogen-evolution activity of ZnGa2O4/N-rGO heterostructures

Schematic diagram of photocatalytic hydrogen-evolution of ZnGa₂O₄/N-rGO illustrating that N-rGO acted as a catalyst support and electron sink for promoting charge separation and transfer.

Synergistic effect of rare earth metal Sm oxides and Co1−xS on sheet structure MoS2 for photocatalytic hydrogen evolution

The novel composite Sm₂O₃@Co_1−xS/MoS₂ has high photocatalytic activity and stability, the electron transfer and the charge separation were obviously improved with the synergistic effects of Sm₂O₃ and Co_1−xS on the surface of MoS₂.

Ionic liquid assisted hydrothermal syntheses of Au doped TiO2 NPs for efficient visible-light photocatalytic hydrogen production from water, electrochemical detection and photochemical detoxification of hexavalent chromium (Cr6+)

Au/TiO₂ NPs have been successfully prepared via ionic liquid assisted hydrothermal method and utilizing Au/TiO₂ NPs for photocatalytic hydrogen production and photochemical and electrochemical reduction of Cr⁶⁺ to Cr³⁺.

Graphene in Photocatalysis: A Review

In recent years, heterogeneous photocatalysis has received much research interest because of its powerful potential applications in tackling many important energy and environmental challenges at a global level in an economically sustainable manner. Due to their unique optical, electrical, and physicochemical properties, various 2D graphene nanosheets-supported semiconductor composite photocatalysts have been widely constructed and applied in different photocatalytic fields. In this review, fundamental mechanisms of heterogeneous photocatalysis, including thermodynamic and kinetics requirements, are first systematically summarized. Then, the photocatalysis-related properties of graphene and its derivatives, and design rules and synthesis methods of graphene-based composites are highlighted. Importantly, different design strategies, including doping and sensitization of semiconductors by graphene, improving electrical conductivity of graphene, increasing eloectrocatalytic active sites on graphene, strengthening interface coupling between semiconductors and graphene, fabricating micro/nano architectures, constructing multi-junction nanocomposites, enhancing photostability of semiconductors, and utilizing the synergistic effect of various modification strategies, are thoroughly summarized. The important applications including photocatalytic pollutant degradation, H₂ production, and CO₂ reduction are also addressed. Through reviewing the significant advances on this topic, it may provide new opportunities for designing highly efficient 2D graphene-based photocatalysts for various applications in photocatalysis and other fields, such as solar cells, thermal catalysis, separation, and purification.

Photocatalytic Water Splitting-The Untamed Dream: A Review of Recent Advances

Photocatalytic water splitting using sunlight is a promising technology capable of providing high energy yield without pollutant byproducts. Herein, we review various aspects of this technology including chemical reactions, physiochemical conditions and photocatalyst types such as metal oxides, sulfides, nitrides, nanocomposites, and doped materials followed by recent advances in computational modeling of photoactive materials. As the best-known catalyst for photocatalytic hydrogen and oxygen evolution, TiO₂ is discussed in a separate section, along with its challenges such as the wide band gap, large overpotential for hydrogen evolution, and rapid recombination of produced electron-hole pairs. Various approaches are addressed to overcome these shortcomings, such as doping with different elements, heterojunction catalysts, noble metal deposition, and surface modification. Development of a photocatalytic corrosion resistant, visible light absorbing, defect-tuned material with small particle size is the key to complete the sunlight to hydrogen cycle efficiently. Computational studies have opened new avenues to understand and predict the electronic density of states and band structure of advanced materials and could pave the way for the rational design of efficient photocatalysts for water splitting. Future directions are focused on developing innovative junction architectures, novel synthesis methods and optimizing the existing active materials to enhance charge transfer, visible light absorption, reducing the gas evolution overpotential and maintaining chemical and physical stability.

Ultrathin nanosheets of palladium in boosting its cocatalyst role and plasmonic effect towards enhanced photocatalytic hydrogen evolution

Large surface area for catalytic reaction/light absorption and large interfacial area with semiconductor for charge transfer highlight the ultrathin metal nanosheets as ideal cocatalyst and plasmonic agent in photocatalytic hydrogen evolution.

Visible light active CdS nanorods: one-pot synthesis of aldonitrones

A new CdS nanorod was synthesized and it was used in the one-pot synthesis of aldonitrones under blue LED irradiation.

Optimization of CdS@MoS2 core–shell nanorod arrays for an enhanced photo-response for photo-assisted electrochemical water splitting under solar light illumination

We prepared CdS@MoS₂ core–shell nanorod arrays using a hydrothermal method, followed by electrodeposition.

Enhancement of photocatalytic H2 production activity of CdS nanorods by cobalt-based cocatalyst modification

The excellent photocatalytic H₂ production activity of Co₃O₄–CdS nanocomposite was mainly attributed to the formation of p–n heterojunctions between the p-type Co₃O₄ nanoclusters and n-type CdS nanorods, which could promote the photoinduced charge transfer and separation.

Magnetoelectrodeposition of Ni–W alloy coatings for enhanced hydrogen evolution reaction

The electrocatalytic efficiency of electrodeposited (ED) Ni–W alloy coatings for the hydrogen evolution reaction (HER) has been improved drastically through magnetoelectrodeposition (MED) approach.

Synergetic effect of CoNPs and graphene as cocatalysts for enhanced electrocatalytic hydrogen evolution activity of MoS2

Highly active and stable electrocatalyst for hydrogen evolution have been developed on the basis of molybdenum sulfide on CoNPs–graphene hybrid support via a modified hydrothermal method.

A solid-state approach to fabricate a CdS/CuS nano-heterojunction with promoted visible-light photocatalytic H2-evolution activity

CdS/CuS nano-heterojunction composites were synthesized by the solid-state strategy and exhibited the enhanced visible-light photocatalytic H₂-evolution activity.

A nitrogen and sulphur functionalized graphene oxide–palladium nanoparticle hybrid catalyst for an efficient Heck coupling

A nanohybrid of Pd on GO functionalized with N and S has been fabricated, and demonstrated as an efficient catalyst for Heck coupling with a substantially low catalytic loading (0.02 mol%).

Light-driven removal of rhodamine B over SrTiO3 modified Bi2WO6 composites

Heterostructures are closely related to enhanced photocatalytic function of SrTiO₃/Bi₂WO₆ hybrids.

Importance of the structural integrity of a carbon conjugated mediator for photocatalytic hydrogen generation from water over a CdS–carbon nanotube–MoS2 composite

CdS quantum dots is shown to promote photocatalytic hydrogen production from water significantly over single-layer MoS₂ on double-walled carbon nanotube.