Pristine MoS2 Research Articles

Stability and reversibility of organic molecule modifications of CVD-synthesized monolayer MoS2.

We investigated the stability of monolayer MoS2samples synthesized using chemical vapor deposition (CVD) and subsequently modified with organic molecules under ambient conditions. By analyzing the optical signatures of the samples using photoluminescence spectroscopy (PL), Raman spectroscopy, and surface quality using atomic force microscopy (AFM), we observed that this modification of monolayer MoS2with organic molecules is stable and retains its optical signature over time under ambient conditions. Furthermore, we show the reversibility of the effects induced by the organic molecules, as heating the modified samples restores their original optical signatures, indicating the re-establishment of the optical properties of the pristine monolayer MoS2.

Enhanced NO2 Gas Sensing in Nanocrystalline MoS2 via Swift Heavy Ion Irradiation: An Experimental and DFT Study.

Nanostructured transition metal dichalcogenides (TMDs) like MoS2 hold promise for gas sensing applications due to their exceptional properties. However, limitations exist in maximizing sensor performance, such as limited active sites for gas interaction and sluggish response/recovery times. This study explores swift heavy ion (SHI) irradiation as a strategy to address these challenges in MoS2-based NO2 gas sensors. MoS2 nanoflakes were fabricated and subsequently irradiated with 120 MeV silver (Ag) ions to induce structural and morphological modifications. Characterization techniques confirmed the formation of Mo and S vacancies within the MoS2 lattice due to irradiation. Significantly, SHI irradiation resulted in a remarkable enhancement of approximately 3 times improvement in sensing response compared to pristine MoS2 sensors. Additionally, the irradiated sensors exhibit substantial improvements in both response and recovery times for NO2 detection. SHI irradiation resulted in the formation of self-affine nanostructures and increased grain fragmentation as fluence rises. This enhanced surface area is hypothesized to promote gas-sensor response. To gain deeper insights into the underlying mechanism, first-principles calculations were employed. These calculations suggest that electron transfer occurs from the MoS2 surface to the NO2 molecule during interaction. Furthermore, the irradiation-induced vacancies facilitate stronger NO2 adsorption on the MoS2 surface compared to the pristine sample. This work demonstrates the effectiveness of SHI irradiation in engineering defects within MoS2 nanoflakes, leading to significantly improved NO2 gas-sensing performance. This approach offers a promising avenue for developing next-generation TMD-based gas sensors with enhanced sensitivity, response times, and stability.

Enhanced Photoelectrochemical Water Splitting of In2S3 Photoanodes by Surface Modulation with 2D MoS2 Nanosheets.

Photoanodes with ample visible-light absorption and efficient photogenerated charge carrier dynamics expedite the actualization of high-efficiency photoelectrochemical water splitting (PEC-WS). Herein, we fabricated the heterojunction nanostructures of In2S3/MoS2 on indium-doped tin oxide glass substrates by indium sputtering and sulfurization, followed by the metal-organic chemical vapor deposition of 2D MoS2 nanosheets (NSs). The photocurrent density of In2S3/MoS2 was substantially enhanced and higher than those of pristine In2S3 and MoS2 NSs. This improvement is due to the MoS2 NSs extending the visible-light absorption range and the type-II heterojunction enhancing the separation and transfer of photogenerated electron-hole pairs. This work offers a promising avenue toward the development of an efficient photoanode for solar-driven PEC-WS.

Monolayer MoS[formula omitted] CVD-growth on SiC substrates assisted with KCl

This study examines the growth of molybdenum disulfide (MoS2) on semi-insulating silicon carbide (SI-6H-SiC) substrates using chemical vapor deposition (CVD). Raman and photoluminescence measurements were utilized to characterize pristine and grown with a potassium chloride (KCl) nucleation promoter MoS2. The Raman spectra showed a frequency difference (Δω) of 18.7 cm−1 between the A1g and E2g modes for pristine MoS2, confirming its monolayer nature, while KCl-modified MoS2 exhibited a Δω of 20.4 cm−1. Pristine MoS2 demonstrated compressive strain due to lattice mismatch, with values up to −1.4%, and a low dependency of charge doping shift on Δω. Conversely, KCl-modified MoS2 flakes showed smaller strain, up to −0.4%, and a significant dependency of charge doping shift on Δω. Electrical characterization of 2-Terminal devices indicated a ratio of the high-resistance state to low-resistance state close to 1 for pristine MoS2 and 1.75 for KCl-modified MoS2. Low-temperature photoluminescence measurements suggest that the observed behavior is due to the interaction of MoS2 with KCl.

Enhanced VOCs adsorption on Group VIII transition metal-doped MoS2: A DFT study

Volatile organic compounds (VOCs) represent a significant category of toxic and harmful air pollutants. Among the various abatement techniques available for VOCs, adsorption technology is widely recognized as a cost-effective solution. In this study, density functional theory (DFT) was employed to calculate and compare the adsorption capacities of six typical VOCs on pristine MoS2 and MoS2 modified with Group VIII (MVIII) transition metals atoms. It is found that MVIII-MoS2 monolayer demonstratesa significant enhancement in adsorption capabilities for VOCsrelative to pristine MoS2. Among these Group VIII transition metals atoms, Fe, Ru and Os atoms exhibited the most significant VOCs adsorption enhancement, with Fe atoms demonstrating a particularly pronounced effect. This suggests a synergistic interaction between the metal dopants and the substrate. Density of states (DOS) and charge density difference analyses provided further insights into the mechanisms underlying improved adsorption capability. Interestingly, the introduction of MVIII atoms results in the emergence of a novel state density within the surface state of MoS2, thereby facilitating enhanced electron transfer between VOCs and the substrate. Charge density difference calculations further corroborated these findings, with certain configurations exhibiting significant electron cloud overlap. Such modification leads to more active electron transfer, thereby increasing the substrate’s affinity for VOC molecules and consequently improving the adsorption efficiency. The findings not only enhance the comprehension of VOC adsorption mechanisms on MoS2 but also underscore the potential of metal-doped two-dimensional materials for environmental applications.

A study on the evolution of hydrothermally synthesized MoS2 on thermal annealing and development of novel MoS2-MoO3 hybrid nanostructure for supercapacitor applications

The electrochemical capacitor also known as supercapacitor is a high-performance energy storage device with exceptional properties. We report the evolution of structural, morphological, optical, and thermal properties of MoS2 on thermal annealing along with its supercapacitor study. The pristine MoS2 is synthesized via the hydrothermal method at 200°C and the material is annealed in the presence of air at 250°C, 300°C, and 350°C. The 300°C annealed sample has shown a hybrid MoO3-xMoS2-y phase characterized by morphology of mixed flower-like and nano brick-like structures, marking the first time report of this novel formation. The evolution of the novel MoO3-xMoS2-y phase can be attributed to the intervention of lattice and interstitial oxygen species during synthesis. Electrochemical analysis is employed to study the supercapacitor nature of the materials. The electrochemical study revealed that the hybrid structure has a higher charge storage capacity than MoS2 or MoO3. The calculated specific capacitance from the galvanostatic charge-discharge curve of MoO3-xMoS2-y in 0.1M NaOH is observed to be 1.71mF/cm2, five times greater than other samples. Furthermore, the capacitor behavior of MoO3-xMoS2-y is studied in different electrolytes such as KOH, NaOH, and Na2SO4 at a concentration of 3M. The intercalation-assisted faradaic process is observed to be the major charge storage mechanism of the hybrid structure. Developing novel nanostructures with distinct properties is crucial for advancing supercapacitors to achieve optimal performance.

Enhanced photocatalytic degradation of Cr (VI) and organic pollutants using novel 3D/2D MoS2/SnS2 heterostructures for water remediation

In this study, 3D flower-like MoS2 nanostructures were synthesized using a hydrothermal technique to form heterostructures with 2D porous SnS2 nanosheets. The resulting 3D/2D MoS2/SnS2 heterostructures were evaluated for their photocatalytic abilities in removing Cr (VI), tetracycline (TC), and methylene blue (MB) under simulated solar irradiation. The results demonstrate that the MoS2/SnS2 heterostructures significantly outperformed pristine MoS2 and SnS2 in photocatalytic efficiency. Specifically, the MoS2/SnS2 photocatalysts achieved 99.9% degradation of Cr (VI) within 50 min, 96% degradation of TC in the same timeframe, and 99.9% elimination of MB in just 10 min. The reduction rate constant for Cr (VI) reduction by MoS2/SnS2 photocatalysts was 0.117 min−1, surpassing that of pure SnS2 (0.007 min−1) and MoS2 (0.0034 min−1) by 16 and 30 times, respectively. This outstanding performance is attributed to the heterojunction formation between SnS2 and MoS2, which suppresses the recombination of photogenerated charge carriers and provides abundant reactive sites due to their large specific surface area. The proposed photodegradation mechanism illustrates the facilitated migration of photogenerated charge carriers under light irradiation, enabled by the energy band alignment at the MoS2/SnS2 interface. These findings represent a significant advancement in the development of photocatalysts based on 3D flower-like MoS2 and porous SnS2 nanostructures, offering promise for applications in wastewater treatment and environmental remediation.

Synergistic Schottky contacts & diatomic doping in Cr/P-MoS2@Ti3C2Tx with boosted energy storage performance

Molybdenum disulfide (MoS2), despite its promising attributes, suffers from low conductivity and aggregation. Herein, we introduce a novel approach that integrates Schottky contacts with Cr/P diatomic doping in MoS2@Ti3C2Tx, significantly enhancing its performance. The Schottky contacts effectively suppress aggregation and accelerate interfacial charge transfer, while Cr/P doping boosts conductivity, active sites, and stability. As a result, the Cr/P-MoS2@Ti3C2Tx electrode exhibits a specific capacitance of 650 F g-1 at 1 A g-1, which is fourfold higher than that of pristine MoS2. When assembled into an asymmetric supercapacitor (Cr/P-MoS2@Ti3C2Tx//AC ASC), the device achieves a peak energy density of 32 Wh kg-1 at 303 W kg-1, maintaining 85% capacitance retention after 10,000 cycles with an impressive coulombic efficiency of 97%. Furthermore, the density functional theory (DFT) calculations validate the beneficial effects of Schottky contacts and diatomic doping on the improved energy storage performance of Cr/P-MoS2@Ti3C2Tx. This work demonstrates the promising potential of the material for applications in high-performance supercapacitors (SCs).

Atomic Basal Defect-Rich MoS2 by One-Step Synthesis and Mechanism Exploration.

Two-dimensional molybdenum disulfide (2D MoS2) shows great promise as a surface-enhanced Raman scattering (SERS) substrate due to its strong exciton resonance. However, the inert basal plane limits the performance of SERS. In this work, a strategy is proposed for the one-step synthesis of atomically basal defect-rich MoS2. The study first reveals that NaCl plays a two-stage role in the growth process, where NaCl initially promotes the rapid growth of large MoS2 as previously reported, and then promotes the formation of atomic basal defects dominated by single sulfur vacancies. Additionally, spectral changes induced by modulation of experimental parameters and density function theory calculation show that defect generation occurs during cooling. Meanwhile, the ratio of to A1g in defect-rich MoS2 exhibits different variation trends compared with pristine MoS2 in power-dependent Raman, and the ratio increases with increasing basal defects. In SERS tests, the limit of detection for rhodamine 6G reached 10-9m, which is comparable to the performance of conventional noble metal SERS substrate. The activation strategy of the inert basal plane is applicable to other 2D transition metal dichalcogenides, and further has the potential to enhance performance in other domains, such as SERS and hydrogen evolution reactions.

Impact of Atomic Defects on Water Contact Angle of 2D Molybdenum Disulfide Surfaces.

Interfacial dynamics within nanofluidic systems are crucial for applications like water desalination and osmotic energy harvesting. Understanding these dynamics can inform the rational optimization of two-dimensional (2D) materials and devices for such applications. This study explores the wetting behavior of realistic 2D MoS2 surfaces incorporating vacancies and atomic steps, known as atomic defects. We employ a combined density functional theory (DFT) and molecular dynamics (MD) computational approach to elucidate the influence of atomic defects on the MoS2-water interface. DFT calculations are utilized to determine the charge distribution within MoS2. Subsequently, free energy calculations are obtained through MD simulations of the MoS2-water interface. Our findings underscore the importance of incorporating atomic defects into MoS2 surfaces for accurate water contact angle (WCA) predictions in nanofluidic simulations, particularly when using Abal et al. force field parameters. However, the force field developed by Liu et al. yielded more accurate results for pristine MoS2 surfaces. While these parameters provide reliable outcomes for pristine MoS2 surfaces, their application to surfaces with defects may lead to underestimation of WCA. This highlights the critical need for realistic surface representations in nanofluidic modeling to accurately capture the complex interactions between water and MoS2 materials.

Significant Enhancement in THz Emission and Piezoelectricity in Atomically Thin Nb-Doped MoS2.

A significantly enhanced THz radiation generation from femtosecond photoexcited MoS2 layers due to Nb-doping is reported here. Different microscopic mechanisms involved in the THz photocurrent generation vary in their relative contributions in the two cases of photoexcitation, i.e., above and below the electronic bandgap of the layers. For a moderate Nb-doping level of just ∼0.05%, we have observed a multifold enhancement in the THz emission for the case of the above bandgap excitation, which is, though, nearly 1.5 times for the case of the below bandgap excitation of the monolayer MoS2. Alongside the difference in THz generation efficiency, the THz pulse polarity is also reversed at the above bandgap excitation of the Nb-doped layers, consequent to the reversed surface depletion field. Except for a slightly smaller difference in the THz enhancement factor, all the observations are reproducible in the bilayers as well to imply a weaker inversion symmetry and reduced screening of the surface depletion field due to Nb-doping. Furthermore, we employed pristine MoS2 and Nb-doped MoS2 monolayers to fabricate piezoelectric nanogenerator devices. Like enhancement in the ultrafast THz emission, the piezoelectric performance of the nanogenerator, fabricated with the Nb-doped MoS2 monolayer is also increased by a similar factor.

Preparation of MoS2/V2O5 nanocomposites for ciprofloxacin degradation and Cr (VI) reduction

In this study, MoS2/V2O5 nanocomposites are obtained by hydrothermal process, and used for photocatalytic system of Ciprofloxacin (CIP) degradation and Cr (VI) reduction. Owing to its novel characteristics, MoS2/V2O5 heterojunctions are revealed as potential semiconductors in this region. V2O5 photocatalyst acts as a charge acceptor, meantime MoS2 acts as an electron donor, therefore promoting charge carrier separation and enhancing photocatalytic efficiency. The MoS2/V2O5 nanocomposites displayed enhanced photocatalytic CIP (98.7 %) and Cr (VI) reduction (98.8 %) after 120 min and 100 min of visible light activity. In contrast, in the first cycle, the photocatalysis capability of the photocatalyst performed in six cycles is 93.8 %. The Kapp values of MoS2/ V2O5 nanocomposites displayed about 11.2 and 19.5-times improvement of photocatalytic of CIP degradation and Cr (VI) reduction, respectively. The MoS2/V2O5 nanocomposites exhibited an enhanced photocurrent density of 0.082 μA/cm−2 compared to a pristine MoS2 sample of 0.045 μA/cm−2. The distinguished heterojunction photocatalysis performance is due to the significant migration of interfacial charges and the inhibited recombination rate of electron-hole pairs. CIP Pollutants eventually decay into H2O, CO2, and small molecule intermediates by generating •O2-, •OH, and h+. The influences of reactive radicals follow the order of •O2- radicals > h+ radicals > •OH radicals. Then, the probable structures of intermediates and achievable photodegradation pathways were discussed for the removal of CIP and Cr (VI) reduction using nanocomposite with visible light response.

Thermally stable photosensing using poly(methyl methacrylate)-coated MoS2 phototransistor for improved imaging reliability

In this paper, we report thermally stable photosensing using MoS2 phototransistor with a poly(methyl methacrylate) (PMMA) coating. The increase in the OFF current of the PMMA-coated MoS2 phototransistor degraded to less than 87.72% of that of the pristine MoS2 phototransistor under harsh temperature conditions (250 °C). PMMA coating on the pristine MoS2 phototransistor improved the photosensitivity and drain current stability as a function of time by 315.71% at 250 °C and 91.26% under intense negative bias temperature illumination stress (NBTIS) test (V gs = −30 V, V ds = 10 V, λ ex = 638 nm, P inc = 1.0 mW, and T = 250 °C), respectively. This simple and useful method provides valuable insight for improving the reliability of photodetectors and image sensor systems under harsh temperature.

Optimized energy storage with hydrothermally synthesized metal sulfide nanocomposite electrodes

Supercapacitors exhibit impressive energy storage capabilities, providing high power density and quick charge/discharge cycles across various applications, including electronics and renewable energy systems. Molybdenum disulfide (MoS2) plays a crucial role in enhancing supercapacitor performance through its high surface area, conductivity, and electrochemical stability. Recent reports have shown that manipulating phase transitions and incorporating dopants or substitutions can significantly enhance the performance of 2D materials. The present study investigated the influence of tungsten substitution on the phase changes and electrochemical properties of MoS2. The hydrothermal synthesis process involved the substitution of tungsten with different concentration, leading to a notable phase change from 2 H to 1 T, as confirmed by X-ray diffraction (XRD) analysis. Morphological studies using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) revealed modifications in the morphological structure. The electrochemical performance of pristine MoS2 and MoS2/WS2 composites were evaluated using cyclic voltammetry (CV), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS). The determined specific capacitances of MoS2/WS2 composites exhibited higher values compared to pristine MoS2. Specifically, the sample with 15 mol% tungsten addition demonstrated a maximum specific capacitance of 333 F g−1, surpassing that of pristine MoS2 and other samples at a current density of 1 A g−1. This research provides valuable insights into the phase-dependent electrochemical behaviour of MoS2 with tungsten substitution, offering a better understanding of its potential for applications in high-performance energy storage devices.

OFS-EFPI ultra-fine manometer based on nitrogen-doped MoS2 diaphragm

Here, an extrinsic Fabry-Pérot interferometer-based optical fiber sensor is introduced to assess its dynamic/static response according to the acoustic/gas pressure performance. This sensor utilizes nitrogen-doped molybdenum disulfide (N-MoS2) and pristine MoS2 diaphragms. The N-MoS2 nanosheets are synthesized using the pulse laser ablation in liquid nitrogen. According to empirical results, the N-MoS2 diaphragm notably enhances the sensitivity of the sensor against the pristine one. Moreover, both diaphragms exhibit a linear relationship between sensor output and acoustic pressure, demonstrating a nearly flat acoustic frequency response ranging 8 Hz-10 kHz. Regarding the pressure measurements, the spectral sensitivity of the N-MoS2 diaphragm is ∼16 % larger than that of pristine. This sensor is capable of measuring the manometric pressures up to 250 mbar with an accuracy of 0.001 mbar.

NO sensing properties of MoS2/WSe2 heterostructure at room temperature under UV light irradiation

Transition metal dichalcogenides (TMDs) have recently sparked interest in gas-sensing applications. Generally, the kinetics of gases show minimal reactivity when the sensor is operable at room temperature (RT). Photon excitation is a potential solution for enhancing gas kinetics at RT. The present study delves gas sensing properties of MoS2/WSe2 heterostructure, emphasizing its effectiveness in detecting a broad range of NO concentration (0.1 ppm to 10 ppm) at room temperature using UV-light (266 nm & 355 nm) as a catalyst. The results reveal a remarkable 13x & 5x amplification in NO detection at 10 ppm for MoS2/WSe2 heterostructure compared to pristine WSe2 and MoS2, which were primarily tested. The highest relative sensor response of 95.4 % is reported for 10 ppm of NO gas at RT under 266 nm illumination. The sensing results revealed a substantial reduction in the limit of detection (LOD) to around 16 ppb, followed by a swift response speed of 10.31/14.38 seconds. The synergistic combination of WSe2 and MoS2 and their high specific surface area enhance NO sensitivity under UV exposure. The fabricated device holds substantial importance in environmental monitoring and healthcare, paving the way for real-time data acquisition in gas sensing.

Rational integration of MoSe2 and BN with TiO2 to design nanoengineered ternary heterojunctions for sustainable hydrogen energy: Experimental evidences and theoretical anticipations

Ternary MoSe2-BN/TiO2 and binary MoSe2–TiO2 heterostructures are epitomized as Tortoise and Hare nanocatalysts to outline the synergism between bilayered MoSe2-BN over pristine MoSe2 for their applicability in the photochemical and photo/-electrochemical water splitting operations. We report here the fabrication of MoSe2-BN integrated TiO2 catalytic systems and ascertained experimental and theoretical investigations of MoSe2-BN/TiO2 and MoSe2–TiO2 heterostructures that are directly proportional to their long-term applicability as the hydrogen evolution reaction (HER) catalysts. Optimized 5 wt% MoSe2-BN/TiO2 and 7.5 wt% MoSe2–TiO2 exhibited nearly 32-fold and 18-fold higher photochemical hydrogen evolution efficiency than bare TiO2 with 43.1% and 25.08% apparent quantum yield, respectively. Photo/-electrochemical studies verified the diversity of MoSe2-BN/TiO2 and MoSe2–TiO2 catalysts as applied potential values diminished drastically to attain benchmark 10 mA/cm2 current density for 5 wt % MoSe2-BN/TiO2 (0.31 V) and 7.5 wt% MoSe2–TiO2 (0.61 V). This work showcases the augmented HER activity of MoSe2-BN/TiO2 due to the shielding of MoSe2 grain boundaries via BN-encapsulation that impeded the degradation of MoSe2 in aqueous condition ascribed to its wide band energy in UV region making it the advanced tunnel barrier.

Synergistic effects of sulfur vacancies and internal electric fields in FeS/MoS2 heterojunctions: A new approach to photocatalytic chromium removal

Molybdenum disulfide (MoS2) is heralded as an exemplary two-dimensional (2D) functional material, largely attributed to its distinctive layered structure. Upon forming heterojunctions with reducing species, MoS2 displays remarkable photocatalytic properties. In this research, we fabricated a novel heterojunction photocatalyst, FeS/MoS2-0.05, through the integration of FeS with hollow MoS2. This composite aims at the efficient photocatalytic reduction of hexavalent chromium (Cr(VI)). A comprehensive array of characterization techniques unveiled that MoS2 flakes, dispersed on FeS, provide numerous active sites for photocatalysis at the heterojunction interface. The inclusion of FeS seemingly promotes the formation of sulfur vacancies on MoS2. Consequently, this heterojunction catalyst exhibits photocatalytic activity surpassing pristine MoS2 by a factor of 3.77. The augmented activity of the FeS/MoS2-0.05 catalyst is attributed chiefly to an internal electric field at the interface. This field enhances the facilitation of charge transfer and separation significantly. Density functional theory (DFT) calculations, coupled with experimental analyses, corroborate this observation. Additionally, DFT calculations indicate that sulfur vacancies act as pivotal sites for Cr(VI) adsorption. Significantly, the adsorption energy of Cr(VI) species shows enhanced favorability under acidic conditions. Our results suggest that the FeS/MoS2-0.05 heterojunction photocatalyst presents substantial potential for the remediation of Cr(VI)-contaminated wastewater.

Molybdenum sulfide modified with nickel or platinum nanoparticles as an effective catalyst for hydrogen evolution reaction

In this study, we investigate the catalytic performance of molybdenum sulfide (MoS2) modified with either nickel (Ni) or platinum (Pt) nanoparticles as catalysts for the hydrogen evolution reaction (HER). The MoS2 was prepared on the TiO2 nanotube substrates via a facile hydrothermal method, followed by the deposition by magnetron sputtering of Ni or Pt nanoparticles on the MoS2 surface. Structural and morphological characterization confirmed the successful incorporation of Ni or Pt nanoparticles onto the MoS2 support. Electrochemical measurements revealed that Ni- and Pt-modified MoS2 catalysts exhibited enhanced HER activity compared to pristine MoS2. Obtained catalysts demonstrated a low onset potential, reduced overpotential, and increased current density, indicating efficient electrocatalytic performance. Furthermore, the Ni or Pt-modified MoS2 catalyst exhibited remarkable stability during prolonged HER operation. The improved catalytic activity can be attributed to the synergistic effect between metal nanoparticles and MoS2, facilitating charge transfer kinetics and promoting hydrogen adsorption and desorption. Incorporating Ni and Pt nanoparticles also provided additional active sites on the MoS2 surface, enhancing the catalytic activity.

Tailoring Heterojunctions in CsPbBrxCl3−x−MoS2 Composites for Efficient Photocatalysis and Hydrogen Evolution

AbstractWe demonstrate appropriate tuning of heterojunctions in CsPbBrxCl3−x−MoS2 composites (where x=0,1,2,3) by controlled regulation of the halide stoichiometry in the perovskite. A thorough optimization procedure determined the most effective photocatalyst, considering the pristine MoS2, perovskites with varying halide ratios, various physical mixing ratios of the two, and in‐situ synthesized composite ratios of CsPbBrxCl3−x and MoS2 (2 : 1, 1.5 : 1, 1 : 1, 1 : 1.5, 1 : 2). Under two hours of exposure to visible light, a remarkable photocatalytic performance of CsPbBrCl2 : MoS2 with a 1 : 2 ratio was observed, removing 98 % of the methylene blue (MB) dye. Notably, only the CsPbBrCl2 and MoS2 composite demonstrated higher efficiencies since it resulted in a n‐n type II heterojunction. Additionally, the CsPbBrCl2 : MoS2 composite exhibits the highest reaction rate constant, fifteen times higher than the pristine perovskite. Reusability assessment of this combination revealed sustained activity of 87 % for up to 5 cycles. The hydrogen evolution reaction investigations were carried out using the optimized CsPbBrCl2 : MoS2 composite, which yielded 265 times more hydrogen than pristine CsPbBrCl2. The Faradaic efficiency for 1 : 2 CsPbBrCl2 : MoS2 was found to be 96.61 %. Our results offer crucial perspectives on optimizing perovskite‐MoS2 composites and demonstrate their utility in sustainable applications, including water treatment, renewable energy harvesting, and environmental remediation.