Au NPs@MoS2 Sub‐Micrometer Sphere‐ZnO Nanorod Hybrid Structures for Efficient Photocatalytic Hydrogen Evolution with Excellent Stability

MoS₂ shows promising applications in photocatalytic water splitting, owing to its uniquely optical and electric properties. However, the insufficient light absorption and lack of performance stability are two crucial issues for efficient application of MoS₂ nanomaterials. Here, Au nanoparticles (NPs)@MoS₂ sub‐micrometer sphere‐ZnO nanorod (Au NPs@MoS₂‐ZnO) hybrid photocatalysts have been successfully synthesized by a facile process combining the hydrothermal method and seed‐growth method. Such photocatalysts exhibit high efficiency and excellent stability for hydrogen production via multiple optical‐electrical effects. The introduction of Au NPs to MoS₂ sub‐micrometer spheres forming a core–shell structure demonstrates strong plasmonic absorption enhancement and facilitates exciton separation. The incorporation of ZnO nanorods to the Au NPs@MoS₂ hybrids further extends the light absorption to a broader wavelength region and enhances the exciton dissociation. In addition, mutual contacts between Au NPs (or ZnO nanorods) and the MoS₂ spheres effectively protect the MoS₂ nanosheets from peeling off from the spheres. More importantly, efficiently multiple exciton separations help to restrain the MoS₂ nanomaterials from photocorrosion. As a result, the Au@MoS₂‐ZnO hybrid structures exhibit an excellent hydrogen gas evolution (3737.4 μmol g^?1) with improved stability (91.9% of activity remaining) after a long‐time test (32 h), which is one of the highest photocatalytic activities to date among the MoS₂ based photocatalysts.     

Coupling Interface Constructions of MoS2/Fe5Ni4S8 Heterostructures for Efficient Electrochemical Water Splitting

Water splitting is considered as a pollution‐free and efficient solution to produce hydrogen energy. Low‐cost and efficient electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are needed. Recently, chemical vapor deposition is used as an effective approach to gain high‐quality MoS₂ nanosheets (NSs), which possess excellent performance for water splitting comparable to platinum. Herein, MoS₂ NSs grown vertically on FeNi substrates are obtained with in situ growth of Fe₅Ni₄S₈ (FNS) at the interface during the synthesis of MoS₂. The synthesized MoS₂/FNS/FeNi foam exhibits only 120 mV at 10 mA cm^?2 for HER and exceptionally low overpotential of 204 mV to attain the same current density for OER. Density functional theory calculations further reveal that the constructed coupling interface between MoS₂ and FNS facilitates the absorption of H atoms and OH groups, consequently enhancing the performances of HER and OER. Such impressive performances herald that the unique structure provides an approach for designing advanced electrocatalysts.     

Nickel@Nitrogen‐Doped Carbon@MoS2 Nanosheets: An Efficient Electrocatalyst for Hydrogen Evolution Reaction

Developing cheap, abundant, and easily available electrocatalysts to drive the hydrogen evolution reaction (HER) at small overpotentials is an urgent demand of hydrogen production from water splitting. Molybdenum disulfide (MoS₂) based composites have emerged as competitive electrocatalysts for HER in recent years. Herein, nickel@nitrogen‐doped carbon@MoS₂ nanosheets (Ni@NC@MoS₂) hybrid sub‐microspheres are presented as HER catalyst. MoS₂ nanosheets with expanded interlayer spacings are vertically grown on nickel@nitrogen‐doped carbon (Ni@NC) substrate to form Ni@NC@MoS₂ hierarchical sub‐microspheres by a simple hydrothermal process. The formed Ni@NC@MoS₂ composites display excellent electrocatalytic activity for HER with an onset overpotential of 18 mV, a low overpotential of 82 mV at 10 mA cm^?2, a small Tafel slope of 47.5 mV dec^?1, and high durability in 0.5 H₂SO₄ solution. The outstanding HER performance of the Ni@NC@MoS₂ catalyst can be ascribed to the synergistic effect of dense catalytic sites on MoS₂ nanosheets with exposed edges and expanded interlayer spacings, and the rapid electron transfer from Ni@NC substrate to MoS₂ nanosheets. The excellent Ni@NC@MoS₂ electrocatalyst promises potential application in practical hydrogen production, and the strategy reported here can also be extended to grow MoS₂ on other nitrogen‐doped carbon encapsulated metal species for various applications.     

Ruthenium Nanoparticles on Cobalt‐Doped 1T′ Phase MoS2 Nanosheets for Overall Water Splitting

2D MoS₂ nanostructures have recently attracted considerable attention because of their outstanding electrocatalytic properties. The synthesis of unique Co–Ru–MoS₂ hybrid nanosheets with excellent catalytic activity toward overall water splitting in alkaline solution is reported. 1T′ phase MoS₂ nanosheets are doped homogeneously with Co atoms and decorated with Ru nanoparticles. The catalytic performance of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is characterized by low overpotentials of 52 and 308 mV at 10 mA cm^?2 and Tafel slopes of 55 and 50 mV decade^?1 in 1.0 m KOH, respectively. Analysis of X‐ray photoelectron and absorption spectra of the catalysts show that the MoS₂ well retained its metallic 1T′ phase, which guarantees good electrical conductivity during the reaction. The Gibbs free energy calculation for the reaction pathway in alkaline electrolyte confirms that the Ru nanoparticles on the Co‐doped MoS₂ greatly enhance the HER activity. Water adsorption and dissociation take place favorably on the Ru, and the doped Co further catalyzes HER by making the reaction intermediates more favorable. The high OER performance is attributed to the catalytically active RuO₂ nanoparticles that are produced via oxidation of Ru nanoparticles.     

3D 1T‐MoS2/CoS2 Heterostructure via Interface Engineering for Ultrafast Hydrogen Evolution Reaction

Metallic phase (1T) MoS₂ has been regarded as an appealing material for hydrogen evolution reaction. In this work, a novel interface‐induced strategy is reported to achieve stable and high‐percentage 1T MoS₂ through highly active 1T‐MoS₂/CoS₂ hetero‐nanostructure. Herein, a large number of heterointerfaces can be obtained by interlinked 1T‐MoS₂ and CoS₂ nanosheets in situ grown from the molybdate cobalt oxide nanorod under moderate conditions. Owing to the strong interaction between MoS₂ and CoS₂, high‐percentage of metallic‐phase (1T) MoS₂ of 76.6% can be achieved, leading to high electroconductivity and abundant active sites compared to 2H MoS₂. Furthermore, the interlinked MoS₂ and CoS₂ nanosheets can effectively disperse the nanosheets so as to enlarge the exposed active surface area. The near zero free energy of hydrogen adsorption at the heterointerface can also be achieved, indicating the fast kinetics and excellent catalytic activity induced by heterojunction. Therefore, when applied in hydrogen evolution reaction (HER), 1T‐MoS₂/CoS₂ heterostructure delivers low overpotential of 71 and 26 mV at the current density of 10 mA cm^?2 with low Tafel slops of 60 and 43 mV dec^?1, respectively in alkaline and acidic conditions.     

Synthesis of MoS2 and MoO2 for their applications in H2 generation and lithium ion batteries: a review

Abstract

Scientists increasingly witness the applications of MoS₂ and MoO₂ in the field of energy conversion and energy storage. On the one hand, MoS₂ and MoO₂ have been widely utilized as promising catalysts for electrocatalytic or photocatalytic hydrogen evolution in aqueous solution. On the other hand, MoS₂ and MoO₂ have also been verified as efficient electrode material for lithium ion batteries. In this review, the synthesis, structure and properties of MoS₂ and MoO₂ are briefly summarized according to their applications for H₂ generation and lithium ion batteries. Firstly, we overview the recent advancements in the morphology control of MoS₂ and MoO₂ and their applications as electrocatalysts for hydrogen evolution reactions. Secondly, we focus on the photo-induced water splitting for H₂ generation, in which MoS₂ acts as an important co-catalyst when combined with other semiconductor catalysts. The newly reported research results of the significant functions of MoS₂ nanocomposites in photo-induced water splitting are presented. Thirdly, we introduce the advantages of MoS₂ and MoO₂ for their enhanced cyclic performance and high capacity as electrode materials of lithium ion batteries. Recent key achievements in MoS₂- and MoO₂-based lithium ion batteries are highlighted. Finally, we discuss the future scope and the important challenges emerging from these fascinating materials.     

Ultrathin Ni(0)-Embedded Ni(OH)2 Heterostructured Nanosheets with Enhanced Electrochemical Overall Water Splitting

The efficiency of splitting water into hydrogen and oxygen is highly dependent on the catalyst used. Herein, ultrathin Ni(0)-embedded Ni(OH)₂ heterostructured nanosheets, referred to as Ni/Ni(OH)₂ nanosheets, with superior water splitting activity are synthesized by a partial reduction strategy. This synthetic strategy confers the heterostructured Ni/Ni(OH)₂ nanosheets with abundant Ni(0)-Ni(II) active interfaces for hydrogen evolution reaction (HER) and Ni(II) defects as transitional active sites for oxygen evolution reaction (OER). The obtained Ni/Ni(OH)₂ nanosheets exhibit noble metal-like electrocatalytic activities toward overall water splitting in alkaline condition, to offer 10 mA cm⁻² in HER and OER, the required overpotentials are only 77 and 270 mV, respectively. Based on such an outstanding activity, a water splitting electrolysis cell using the Ni/Ni(OH)₂ nanosheets as the cathode and anode electrocatalysts has been successfully built. When the output voltage of the electrolytic cell is 1.59 V, a current density of 10 mA cm⁻² can be obtained. Moreover, the durability of Ni/Ni(OH)₂ nanosheets in the alkaline electrolyte is much better than that of noble metals. No obvious performance decay is observed after 20 h of catalysis. This facile strategy paves the way for designing highly active non-precious-metal catalyst to generate both hydrogen and oxygen by electrolyzing water at room temperature.     

Porous Cobalt–Nickel Hydroxide Nanosheets with Active Cobalt Ions for Overall Water Splitting

Low‐cost and high‐performance catalysts are of great significance for electrochemical water splitting. Here, it is reported that a laser‐synthesized catalyst, porous Co_0.75Ni_0.25(OH)₂ nanosheets, is highly active for catalyzing overall water splitting. The porous nanosheets exhibit low overpotentials for hydrogen evolution reaction (95 mV@10 mA cm^?2) and oxygen evolution reaction (235 mV@10 mA cm^?2). As both anode and cathode catalysts, the porous nanosheets achieve a current density of 10 mA cm^?2 at an external voltage of 1.56 V, which is much lower than that of commercial Ir/C‐Pt/C couple (1.62 V). Experimental and theoretical investigations reveal that numerous Co³⁺ ions are generated on the pore wall of nanosheets, and the unique atomic structure around Co³⁺ ions leads to appropriate electronic structure and adsorption energy of intermediates, thus accelerating hydrogen and oxygen evolution.     

Structure Engineering of MoS2 via Simultaneous Oxygen and Phosphorus Incorporation for Improved Hydrogen Evolution

Oxygen and phosphorus dual‐doped MoS₂ nanosheets (O,P‐MoS₂) with porous structure and continuous conductive network are fabricated using a one‐pot NaH₂PO₂‐assisted hydrothermal approach. By simply changing the precursor solution, the chemical composition and resulting structure can be effectively controlled to obtain desired properties toward the hydrogen evolution reaction (HER). Thanks to the beneficial structure and strong synergistic effects between the incorporated oxygen and phosphorus, the optimal O,P‐MoS₂ exhibit superior electrocatalytic performances compared with those of oxygen single‐doped MoS₂ nanosheets (O‐MoS₂). Specifically, a low HER onset overpotential of 150 mV with a small Tafel slope of 53 mV dec^?1, excellent conductivity, and long‐term durability are achieved by the structural engineering of MoS₂ via O and P co‐doping, making it an efficient HER electrocatalyst for water electrocatalysis. This work provides an alternative strategy to manipulate transition metal dichalcogenides as advanced materials for electrocatalytic and related energy applications.     

Sustainable Fuel Production from Ambient Moisture via Ferroelectrically Driven MoS2 Nanosheets

Unlike traditional water splitting in an aqueous medium, direct decomposition of atmospheric water is a promising way to simultaneously dehumidify the living space and generate power. Here, a tailored superhygroscopic hydrogel, a catalyst, and a solar cell are integrated into a humidity digester that can break down ambient moisture into hydrogen and oxygen, creating an efficient electrochemical cell. The function of the hydrogel is to harvest moisture from ambient humidity and transfer the collected water to the catalyst. Barium titanate and vertical 2D MoS₂ nanosheets are integrated as the catalyst: the negatively polarized cathode can enhance the electron transport and attract H⁺ to the MoS₂ surface for water reduction, while water oxidation takes place at the positively polarized anode. By employing this mechanism, it is possible to maintain the relative humidity in a medium-sized room at <60% without any additional energy input, and a stable current of 12.5 mA cm⁻² is generated by the humidity digester when exposed to ambient light.     

Surface Engineering of MoS2 via Laser‐Induced Exfoliation in Protic Solvents

With excellent performance in the hydrogen evolution reaction (HER), molybdenum disulfide (MoS₂) is considered a promising nonprecious candidate to substitute Pt‐based catalysts. Herein, pulsed laser irradiation in liquid is used to realize one‐step exfoliation of bulk 2H‐MoS₂ to ultrastable few‐layer MoS₂ nanosheets. Such prepared MoS₂ nanosheets are rich in S vacancies and metallic 1T phase, which significantly contribute to the boosted catalytic HER activity. Protic solvents play a pivotal role in the production of S vacancies and 2H‐to‐1T phase transition under laser irradiation. MoS₂ exfoliated in an optimal solvent of formic acid exhibits outstanding HER activity with an overpotential of 180 mV at 10 mA cm^?2 and Tafel slope of 54 mV dec^?1.     

Ganoderma‐Like MoS2/NiS2 with Single Platinum Atoms Doping as an Efficient and Stable Hydrogen Evolution Reaction Catalyst

Herein, a unique ganoderma‐like MoS₂/NiS₂ hetero‐nanostructure with isolated Pt atoms anchored is reported. This novel ganoderma‐like heterostructure can not only efficiently disperse and confine the few‐layer MoS₂ nanosheets to fully expose the edge sites of MoS₂, and provide more opportunity to capture the Pt atoms, but also tune the electronic structure to modify the catalytic activity. Because of the favorable dispersibility and exposed large specific surface area, single Pt atoms can be easily anchored on MoS₂ nanosheets with ultrahigh loading of 1.8 at% (the highest is 1.3 at% to date). Owing to the ganoderma‐like structure and platinum atoms doping, this catalyst shows Pt‐like catalytic activity for the hydrogen evolution reaction with an ultralow overpotential of 34 mV and excellent durability of only 2% increase in overpotential for 72 h under the constant current density of 10 mA cm⁻².     

In-situ synthesized and photocatalytic performance evaluation of MoS2-C-g-C3N4 heterostructure photocatalyts

The heterostructure between two semiconductor materials that had suitable band edge positions can contribute to the separation of photoelectrons and holes. In this paper, the heterostructure MoS₂-C-g-C₃N₄ photocatalysts were in-situ synthesized at one-pot high temperature processing. The obtained 0.4 MoS₂-C-g-C₃N₄ composites displayed the highest photocatalytic hydrogen evolution activity with a corresponding H₂ evolution rate of 238 μmol g⁻¹h⁻¹, which was about 4.5 times higher than that of 3% C-g-C₃N₄, and the photocatalyts exhibited excellent stability which was used for photocatalytic hydrogen evolution reaction for 12 h. The 0.4 MoS₂-C-g-C₃N₄ sample displayed well degradation activities for MO, MB, RhB, MR and Ar18, and the scavenging studies indicated the major involvement of ·O₂^– radicals in the degradation process. The enhanced photocatalytic activity of MoS₂-C-g-C₃N₄ composite was predominantly attributed to the synergistic effects of type II heterostructure between g-C₃N₄ and MoS₂, which effectively accelerated the transfer and separation of photogenerated charge carriers. Besides, the introduction of noble metal-free MoS₂ co-catalyst further improved visible light absorption and provided more active sites for H₂ evolution reaction. Such work is promising for designing a novel heterostructure photocatalysts for solar-to-fuel conversion and environmental modification.     

Synergism of Geometric Construction and Electronic Regulation: 3D Se‐(NiCo)Sx/(OH)x Nanosheets for Highly Efficient Overall Water Splitting

The exploration of highly efficient electrocatalysts for both oxygen and hydrogen generation via water splitting is receiving considerable attention in recent decades. Up till now, Pt‐based catalysts still exhibit the best hydrogen evolution reaction (HER) performance and Ir/Ru‐based oxides are identified as the benchmark for oxygen evolution reaction (OER). However, the high cost and rarity of these materials extremely hinder their large‐scale applications. This paper describes the construction of the ultrathin defect‐enriched 3D Se‐(NiCo)S_x/(OH)_x nanosheets for overall water splitting through a facile Se‐induced hydrothermal treatment. Via Se‐induced fabrication, highly efficient Se‐(NiCo)S_x/(OH)_x nanosheets are successfully fabricated through morphology optimization, defect engineering, and electronic structure tailoring. The as‐prepared hybrids exhibit relatively low overpotentials of 155 and 103 mV at the current density of 10 mA cm^?2 for OER and HER, respectively. Moreover, an overall water‐splitting device delivers a current density of 10 mA cm^?2 for ≈66 h without obvious degradation.     

Simultaneous Piezoelectrocatalytic Hydrogen-Evolution and Degradation of Water Pollutants by Quartz Microrods@Few-Layered MoS2 Hierarchical Heterostructures

Intense light attenuation in water/wastewater results in photocatalysts exhibiting a low quantum efficiency. This study develops a novel piezoelectrocatalysis system, which involves quartz microrods (MRs) abundantly decorated with active-edge-site MoS₂ nanosheets to form a quartz microrods@few-layered MoS₂ hierarchical heterostructure (QMSH). Through theoretical calculations, it is found that the quartz MRs serve as a parallel-plate capacitor, which is self-powered to provide an internal electric field to the few-layered MoS₂ nanosheets surrounding the quartz MR surfaces, and the piezoelectric potential (piezopotential) effectively facilitates redox reactions with the free carriers in MoS₂. The self-powered quartz MRs in the QMSH present an internal bias to the MoS₂ nanosheets, thus yielding a piezoelectrocatalysis system. An efficient piezoelectrocatalytic hydrogen evolution reaction and decomposition of wastewater without light irradiation can be achieved simultaneously. The second-order rate constant of the QMSH is ≈0.631 L mg⁻¹ min⁻¹, which is 650-fold that of quartz MRs, indicating that the piezoelectric heterostructural catalysts display exceptionally high efficiency on piezoelectrocatalytic redox reactions rather than in the piezocatalytic process. The H₂-production rate of QMSH catalysts approaches ≈6456 µmo1 g⁻¹ h⁻¹ and peaks at ≈16.8 mmol g⁻¹ in 8 h. The piezoelectrocatalytic process may be a promising method for treating industrial wastewater and producing clean energy.     

Engineering 2D Metal–Organic Framework/MoS2 Interface for Enhanced Alkaline Hydrogen Evolution

2D metal–organic frameworks (MOFs) have been widely investigated for electrocatalysis because of their unique characteristics such as large specific surface area, tunable structures, and enhanced conductivity. However, most of the works are focused on oxygen evolution reaction. There are very limited numbers of reports on MOFs for hydrogen evolution reaction (HER), and generally these reported MOFs suffer from unsatisfactory HER activities. In this contribution, novel 2D Co‐BDC/MoS₂ (BDC stands for 1,4‐benzenedicarboxylate, C₈H₄O₄) hybrid nanosheets are synthesized via a facile sonication‐assisted solution strategy. The introduction of Co‐BDC induces a partial phase transfer from semiconducting 2H‐MoS₂ to metallic 1T‐MoS₂. Compared with 2H‐MoS₂, 1T‐MoS₂ can activate the inert basal plane to provide more catalytic active sites, which contributes significantly to improving HER activity. The well‐designed Co‐BDC/MoS₂ interface is vital for alkaline HER, as Co‐BDC makes it possible to speed up the sluggish water dissociation (rate‐limiting step for alkaline HER), and modified MoS₂ is favorable for the subsequent hydrogen generation step. As expected, the resultant 2D Co‐BDC/MoS₂ hybrid nanosheets demonstrate remarkable catalytic activity and good stability toward alkaline HER, outperforming those of bare Co‐BDC, MoS₂, and almost all the previously reported MOF‐based electrocatalysts.     

Extended visible light harvesting and boosted charge carrier dynamics in heterostructured zirconate–FeS<Subscript>2</Subscript> photocatalysts for efficient solar water splitting

Limited visible light absorption, slow charge transference, and high recombination are some of the main problems associated with low efficiency in photocatalytic processes. For these reasons, in the present work, we develope novel zirconate–FeS₂ heterostructured photocatalysts with improved visible light harvesting, effective charge separation and high photocatalytic water splitting performance. Herein, alkali and alkaline earth metal zirconates are prepared by a solid state reaction and coupled to FeS₂ through a simple wet impregnation method. The incorporation of FeS₂ particles induces visible light absorption and electron injection in zirconates, while the appropriate coupling of the semiconductors in the heterostructure allows an enhanced charge separation and suppression of the recombination. The obtained heterostructures exhibit high and stable photocatalytic activity for water splitting under visible light, showing competitive efficiencies among other reported materials. The highest hydrogen evolution rate (4490 µmol g^?1 h^?1) is shown for BaZrO₃–FeS₂ and corresponds to more than 20 times the activity of the bare BaZrO₃. In summary, this work proposes novel visible light active heterostructures for efficient visible light photocatalytic water splitting.     

Incorporating Nitrogen‐Doped Graphene Quantum Dots and Ni3S2 Nanosheets: A Synergistic Electrocatalyst with Highly Enhanced Activity for Overall Water Splitting

A noble‐metal‐free electrocatalyst is fabricated via in situ formation of nanocomposite of nitrogen‐doped graphene quantum dots (NGQDs) and Ni₃S₂ nanosheets on the Ni foam (Ni₃S₂‐NGQDs/NF). The resultant Ni₃S₂‐NGQDs/NF can serve as an active, binder‐free, and self‐supported catalytic electrode for direct water splitting, which delivers a current density of 10 mA cm^?2 at an overpotential of 216 mV for oxygen evolution reaction and 218 mV for hydrogen evolution reaction in alkaline media. This bifunctional electrocatalyst enables the construction of an alkali electrolyzer with a low cell voltage of 1.58 V versus reversible hydrogen electrode (RHE) at 10 mA cm^?2. The experimental results and theoretical calculations demonstrate that the synergistic effects of the constructed active interfaces are the key factor for excellent performance. The nanocomposite of NGQDs and Ni₃S₂ nanosheets can be promising water splitting electrocatalyst for large‐scale hydrogen generation or other energy storage and conversion applications.     

Cobalt Covalent Doping in MoS2 to Induce Bifunctionality of Overall Water Splitting

The layer‐structured MoS₂ is a typical hydrogen evolution reaction (HER) electrocatalyst but it possesses poor activity for the oxygen evolution reaction (OER). In this work, a cobalt covalent doping approach capable of inducing HER and OER bifunctionality into MoS₂ for efficient overall water splitting is reported. The results demonstrate that covalently doping cobalt into MoS₂ can lead to dramatically enhanced HER activity while simultaneously inducing remarkable OER activity. The catalyst with optimal cobalt doping density can readily achieve HER and OER onset potentials of ?0.02 and 1.45 V (vs reversible hydrogen electrode (RHE)) in 1.0 m KOH. Importantly, it can deliver high current densities of 10, 100, and 200 mA cm^?2 at low HER and OER overpotentials of 48, 132, 165 mV and 260, 350, 390 mV, respectively. The reported catalyst activation approach can be adapted for bifunctionalization of other transition metal dichalcogenides.     

2D Transition‐Metal‐Dichalcogenide‐Nanosheet‐Based Composites for Photocatalytic and Electrocatalytic Hydrogen Evolution Reactions

Hydrogen (H₂) is one of the most important clean and renewable energy sources for future energy sustainability. Nowadays, photocatalytic and electrocatalytic hydrogen evolution reactions (HERs) from water splitting are considered as two of the most efficient methods to convert sustainable energy to the clean energy carrier, H₂. Catalysts based on transition metal dichalcogenides (TMDs) are recognized as greatly promising substitutes for noble‐metal‐based catalysts for HER. The photocatalytic and electrocatalytic activities of TMD nanosheets for the HER can be further improved after hybridization with many kinds of nanomaterials, such as metals, oxides, sulfides, and carbon materials, through different methods including the in situ reduction method, the hot‐injection method, the heating‐up method, the hydro(solvo)thermal method, chemical vapor deposition (CVD), and thermal annealing. Here, recent progress in photocatalytic and electrocatalytic HERs using 2D TMD‐based composites as catalysts is discussed.