Rod-shaped Mo( VI ) trichalcogenide – Mo( VI ) oxide decorated on poly(1-H pyrrole) as a promising nanocomposite photoelectrode for green hydrogen generation from sewage water with high e ﬃ ciency

: The synthesis of rod-shaped Mo( VI ) trichalcogenide – Mo( VI ) oxide, cleverly adorned on a poly(1-H pyrrole) (P1HP) matrix (MoS 3 – MoO 3 /P1HP), is achieved through a one-pot preparation method. This process occurs under the pyrrole oxidation employing the oxidizing agent Na 2 MoO 4 . Notably, this oxidation process facilitates the direct incorporation of the inorganic constituents into the polymer matrix. Of particular signi ﬁ cance is the material ’ s bandgap, which is optimally situated at 1.4 eV, rendering it highly suitable for its intended applications. The material assumes a rod-like structure, characterized by an average length of 400 nm and width of 30 nm, further enhancing its desirability. In practice, this thin ﬁ lm serves as an exceptionally promising photoelec-trode. It ﬁ nds its forte in the generation of hydrogen from sewage water, achieving an impressive e ﬃ ciency rate of 12.66%, speci ﬁ cally at 340 nm. In addition to that, it boasts a remarkable hydrogen generation rate of 1.2 moles·h − 1 ·cm − 2 . Moreover, the material exhibits remarkable versatility in its response to light. Its sensitivity to monochromatic light across a broad optical spectrum (UV till IR), underscores its potential for hydrogen generation applications for industrial applications.


Introduction
Conductive polymers represent a captivating and innovative category of electronic materials [1,2].The allure of conductive polymers lies in their unique amalgamation of metallic and polymeric properties, rendering them exceptionally versatile and adaptable for a myriad of applications.Among the plethora of conductive polymers, poly(1-H pyrrole) (P1HP) stands out as an exceptionally compelling choice.Its allure is underscored by a multitude of research publications delving into its electrical properties and the broad spectrum of potential applications it offers.With a conductivity range of about 1.14 S•cm −1 , P1HP has earned its place as a frontrunner in the realm of conductive polymers [3].However, its appeal extends far beyond its electrical prowess; this remarkable material boasts a repertoire of exceptional physicochemical properties that render it a promising candidate for intelligent and adaptive materials.
Capitalizing on its exceptional electrical properties, P1HP extends its influence into the vast domain of the ultraviolet (UV) spectrum.This extension is closely linked to the intriguing phenomenon of electron transitions from the highest unoccupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) states, giving rise to optical behaviors that span the UV region [4].Researchers have diligently pursued avenues to augment the optical characteristics of P1HP, channeling their efforts in two primary directions: Morphological Mastery: The first avenue to enhance the optical performance of P1HP revolves around the meticulous control of its morphological features.Researchers employ strategies to craft this polymer into structures that exhibit exceptional optical properties within the UV range [4].These endeavors encompass the fabrication of P1HP with distinct morphologies that can efficiently capture and interact with UV light.In addition to the synergetic Composites: The second, equally compelling route involves the integration of P1HP with highly optically active inorganic materials.By forming composite materials that combine the unique attributes of P1HP with the optical prowess of inorganic components like NiO, CuO, MnO, MnS, or PbS [5][6][7][8], researchers create materials that open up a vast panorama of opportunities in the realms of optoelectronics and photocatalysis.These composite materials emerge as stellar candidates for a diverse array of optoelectronic and photocatalytic applications, representing a fusion of organic and inorganic worlds to deliver enhanced optical performance and functionality.This synergy not only augments the UV optical behavior but also extends the application spectrum of these materials into hitherto uncharted territories [9][10][11][12][13].The catalytic behavior of the nanocomposite facilitates electron transitions between the composite materials, following a distinctive Z-or S-shaped trajectory as the electron undergoes its transition pathway.Subsequently, the electrons or holes act as effective carriers, instigating supplementary reactions, which may encompass the splitting of water molecules [14,15].
In the realm of renewable energy, with a specific focus on hydrogen generation, P1HP material has found its niche as a photocatalytic substance.However, an inherent limitation of this material lies in the relatively modest quantities of hydrogen gas it can generate, as indicated by the corresponding current density.While P1HP exhibits promising photocatalytic properties for the conversion of water to H 2 , the volume of hydrogen gas produced is constrained by the current density it can generate.This limitation is a critical consideration in the practical application of P1HPbased photocatalysis for hydrogen production.Efforts are underway to optimize and enhance the performance of P1HP photocatalysts, with a particular focus on increasing the current density to augment hydrogen gas yields.Researchers are exploring various strategies, such as modifying the material's composition, improving its morphological characteristics, or integrating it with complementary materials to boost its photocatalytic efficiency [16,17].Overcoming this limitation is pivotal for realizing the full potential of P1HP as a photocatalytic material for green H 2 .As advancements continue in the field of renewable energy, addressing this constraint will be a key step in harnessing P1HP's capabilities to contribute significantly to the sustainable production of hydrogen, a vital component in the transition to a cleaner and greener energy landscape [18,19].
In this study, a groundbreaking composite material known as MoS 3 -MoO 3 /P1HP rods takes the spotlight as an exceptionally promising nanocomposite photoelectrode.This innovative material exhibits remarkable potential for the efficient generation of green hydrogen, and it is put to the test in the context of sewage water treatment.The investigation leaves no stone unturned as it delves into a comprehensive array of analyses.These encompass optical assessments, morphological examinations, elemental characterizations, and crystalline structure evaluations.
The study scrutinizes the photoelectrode's performance under varying conditions, including complete darkness, exposure to white light, and the utilization of monochromatic wavelengths for the hydrogen generation reaction.Furthermore, the investigation extends its scope to calculate two crucial parameters.The incident photon to current efficiency (IPCE) that is evaluated to gauge the photoelectrode's ability to convert incident photons into electrical current.Additionally, the quantity of hydrogen gas produced is meticulously quantified in terms of moles.This comprehensive exploration of the MoS 3 -MoO 3 /P1HP nanocomposite photoelectrode opens up exciting prospects for sustainable hydrogen production from sewage water.By shedding light on the material's behavior in different light conditions and quantifying its performance through IPCE and hydrogen production measurements, the study paves the way for innovative solutions in wastewater treatment and renewable energy generation.Conversely, in the absence of the Na 2 MoO 4 oxidant, a separate process occurs for P1HP thin film formation.In this scenario, the polymerization process proceeds, but the MoS 3 -MoO 3 inorganic filler is not introduced into the polymer network.

Photoelectrochemical reaction of
MoS 3 -MoO 3 /P1HP thin film photocathode for hydrogen generation The photoelectrochemical reaction of the MoS 3 -MoO 3 / P1HP thin film photocathode, aimed at hydrogen generation, is conducted by employing this photocathode as the main electrode.In this configuration, another electrode is introduced, specifically a graphite electrode, serving as the auxiliary electrode.Additionally, a calomel electrode is utilized as the reference electrode.This electrochemical cell is connected to the CHI608E workstation for the precise measurement and monitoring of the electrochemical reactions.
The electrolyte used in this setup consists of sewage water, which has undergone a thorough treatment process within the Beni-Suef city company responsible for drinking and salination.This treated water exhibits a pH level of 7.2.It is important to note that this water has undergone rigorous purification and treatment procedures.
The experiments are conducted under a metal halide lamp.To precisely control the wavelengths of light, optical filters are employed.This enables the systematic study of the photocathode's performance under different lighting conditions.The configuration of the cell used in these experiments is visually represented in Figure 1.Let us examine the primary peaks and their attributions in these spectra:

Analysis processes
In the spectrum of pyrrole (P1HP), absorptions are observed at 681 and 797 cm −1 related to the pare substituted P1HP ring.Prominent absorption peaks centered at 1,045 and 1,177 cm −1 are for the C-H bonds [20].The dominant absorption peak is located around 3,420 cm −1 for the N-H bonds present in the pyrrole amines [21].Peaks centered at 1,621 cm −1 are for C]C bonds within the molecular structure.A peak at 1,545 cm −1 can be assigned to the C]C stretching vibrations originating from the pyrrole rings.The peak appearing at 1,463 cm −1 is linked to the conjugated pyrrole C-N.An intermediate-intensity band at 1,312 cm −1 is for the valence vibrations of the pyrrole C-N bond [22].Overall, the observed FTIR spectrum is in excellent agreement with the proposed molecular structure of pyrrole.These characteristic peaks and their assignments confirm the presence of key functional groups and molecular bonds within the P1HP molecule.Furthermore, the FTIR spectrum of MoS 3 -MoO 3 /P1HP emerges as a valuable instrument for evaluating the structural modifications and interactions occurring in the course of nanocomposite formation with additional shifts compared to the pristine P1HP polymer related to the interaction of the inorganic components with the pristine polymer during the polymer formation [23].This analytical tool aids in clarifying the impact of introducing MoS 3 -MoO 3 on the vibrational properties of the polymer, as evidenced by enhanced peaks at 681 and 797 cm −1 in the composite.These peaks signify the vibrational characteristics associated with Mo-O and Mo-S, shedding light on the alterations induced by the inclusion of MoS 3 -MoO 3 in the composite material.
However, it is noteworthy that both P1HP and MoS 3 exhibit an amorphous nature in this composite.This amorphous behavior is consistent with the known properties of these materials, which have been documented in previous literature.For instance, the broad peaks observed at 12.66°a nd 51.0°for MoS 3 substantiate its amorphous character with its sulfur constituents [25,26].Similarly, the XRD curve for P1HP exhibits broad bands, reinforcing the amorphous nature associated with this polymer material with limited shifts in these broad peaks after the composite formation, related to the behavior of the inorganic materials on the chain network of the pristine P1HP [27].
To determine the crystalline size (D), the Scherrer equation (Eq. 1) is employed [28], utilizing the full-width at half maximum (W) of the high-intensity peak observed at 2ϴ 31.0°,concerning the wavelength of the incidence XRD (λ).The calculation yields a crystalline size value of 65 nm.For a comprehensive understanding of the fabricated MoS 3 -MoO 3 /P1HP nanocomposite's chemical composition, elemental constituents, and oxidation states, XPS analyses were conducted, and the results are shown in Figure 2(c) and (d). Figure 2(c) provides valuable insights into the chemical structure of P1HP.This is evident from the evaluation of the binding energies associated with C and N elements.The binding energies for C and N are identified at 285.4 and 400.3 eV, respectively.Furthermore, the presence of chloride ions (Cl) is detected at 200.4 eV.This presence can be related to the use of hydrochloric acid as both the acid medium and solvent for the monomer during the synthesis process.The presence of Cl − ions is particularly noteworthy for boosting the conductivity of the entire composite due to their favorable interaction with the polymer's nitrogen atoms through Van der Waals forces.Figure 2(d) delves into the characterization of MoS 3 and MoO 3 within the nanocomposite.The binding energies associated with the Mo3d orbital are used to confirm the presence of these compounds.Specifically, Mo3d 5/2 and Mo3d 3/2 binding energies are at 231.4 and 234.3 eV, respectively, which aligns with the characteristics of MoS 3 [29].Meanwhile, for MoO3, the Mo3d 5/2 and Mo3d 3/2 binding energies are at 232.8 and 235.6 eV, respectively [30].
The surface topography and morphological characteristics of both the synthesized P1HP and the MoS 3 -MoO 3 / P1HP nanocomposite are vividly portrayed through SEM images, as depicted in Figure 3(a) and (b), respectively.Let us delve into the observations and insights provided by these images.
In Figure 3(a), the SEM image of P1HP reveals the presence of uniform semi-spherical particles with approximately 250 nm.These particles exhibit a porous nature, and there is a notable degree of porosity between them.This porous structure is particularly advantageous for facilitating the formation of the nanocomposite [31,32].
Upon the formation of the MoS 3 -MoO 3 /P1HP nanocomposite, as illustrated in Figure 3(b), a substantial alteration in morphology becomes evident.The composite material displays a distinctive transformation, with the emergence of rod-like particles.This transformation in morphology can be attributed to the interaction between the inorganic components, MoS 3 -MoO 3 , and the organic component, P1HP, during the polymerization process.This interaction leads to the creation of a novel nanocomposite structure characterized by a distinct diameter [33].
Figure 3(c) offers a closer look at the nanocomposite's morphology through a transmission electron microscopy (TEM) image.In this image, the nanocomposite is composed of rod-shaped particles with an average length of approximately 400 nm and a width of about 30 nm.These nanorods exhibit an intriguing arrangement adorned with additional semi-spherical particlesthese semi-spherical particles are of 75 nm.To gain a more detailed view of these semi-spherical particles, Figure 3(d) provides an enlarged perspective.This image clearly reveals that the semi-spherical particles are not isolated; rather, they are enveloped by an additional thin film.This structural complexity further underscores the intricate and finely tuned composition of the MoS 3 -MoO 3 /P1HP nanocomposite.
So, the SEM and TEM images presented in Figure 3(a)-(d) offer valuable insights into the topography and morphological evolution of both P1HP and the MoS 3 -MoO 3 /P1HP nanocomposite.
In Figure 4(a), the absorbance of pristine P1HP and the MoS 3 -MoO 3 /P1HP nanocomposite are presented, offering critical insights into the materials' optical properties.The P1HP displays two distinct peaks at approximately 295 and 480 nm.These peaks correspond to ᴨ-ᴨ* transitions, aligning with previous findings [34][35][36].The absorbance spectrum of the MoS 3 -MoO 3 /P1HP nanocomposite, on the contrary, exhibits significant changes.There is a pronounced increase in absorbance intensity, with shifts in the second peak position from 480 to 740 nm, suggesting the successful integration of MoS 3 -MoO 3 nanorods into the P1HP matrix.
In Figure 4(b), the bandgap of the synthesized materials is addressed.The bandgap calculation, performed using Tauc's equation [37], yields an E g value of 2.9 eV for P1HP.However, upon the incorporation of MoS 3 -MoO 3 rods, a significant decrease in bandgap to 1.4 eV is observed; this behavior is due to nanorod incorporation [34,38].

Photoelectrochemical testing of the MoS 3 -MoO 3 /P1HP nanocomposite photocathode for green hydrogen generation
The photoelectrochemical assessment of the MoS 3 -MoO 3 / P1HP nanocomposite photocathode for the production of green hydrogen is performed using sewage water with a chemical composition outlined in Table 1.This specific type of sewage water serves as an electrolyte, eliminating the need for any additional synthetic electrolytes.In this unique process, the study capitalizes on the contaminants present in the sewage water as a source of renewable energy.This innovative approach represents an environmentally friendly and sustainable means of harnessing energy from a previously underutilized resource.Furthermore, the utilization of sewage water in this context presents a highly valuable and abundant resource.Sewage water is both readily available and abundant in virtually every corner of the world.Its ubiquity makes it an incredibly valuable asset for this energy conversion process.By tapping into this resource, the study not only addresses the challenge of wastewater management but also transforms a traditionally discarded and problematic substance into a valuable energy source.
In essence, the photoelectrochemical testing of the MoS 3 -MoO 3 /P1HP nanocomposite photocathode in sewage water, as described, not only demonstrates the potential for green hydrogen generation but also showcases a sustainable approach to addressing wastewater challenges.It exemplifies an ingenious way to repurpose and extract value from a resource that is both readily available and abundant, offering significant promise for a more sustainable and energy-efficient future.
Figure 5(a) depicts the current-voltage relationship observed for the MoS 3 -MoO 3 /P1HP nanocomposite photocathode under two distinct conditions: darkness and white light illumination.The graph clearly illustrates discernible current values for the photocathode, denoted as the current density during light exposure (J ph ) and in the absence of light (J o ), highlighting the differences between these contrasting conditions.Specifically, the photocathode yields J ph and J o values of 4.6 and 1.4 mA•cm −2 , respectively, when exposed to white light, whereas these values decrease significantly in the absence of light at −0.85 V.
Figure 5(b) effectively illustrates this behavior by showcasing the impact of alternating light conditions, denoted as chopping on/off light.During this process, the produced current demonstrates a direct correlation with the presence or absence of incident light.This correlation is exemplified by the J ph values, which exhibit substantial changes as the light source is toggled on and off.Notably, the J ph values experience a notable sequential decrease, shifting from −1.07 mA•cm −2 when the light is on to −0.57mA•cm −2 when the light is off.This pronounced alteration highlights two critical aspects of the synthesized MoS 3 -MoO 3 /P1HP nanocomposite photocathode.
First, it underscores the exceptional stability exhibited by the photocathode, as reflected in the consistent current levels observed in both light and dark conditions.This  stability speaks to the robust performance and reliability of the photocathode under varying environmental conditions.Second, it emphasizes the photocathode's remarkable sensitivity to incident photons and its capacity to respond dynamically to changes in light exposure.The increase in J ph under light clearly illustrates this heightened sensitivity.This responsiveness is attributed to the unique light-absorbing properties of the constituent materials, namely MoS 3 , MoO 3 , and P1HP.These materials exhibit diverse absorbance behaviors across different optical regions, effectively capturing photons with varying energies.The sensitivity of the synthesized MoS 3 -MoO 3 /P1HP nanocomposite photocathode to incident photons is effectively assessed by examining the J ph values [13,39] when subjected to monochromatic light, as depicted in Figure 6(a).Additionally, Figure 6(b) displays the resulting J ph values obtained under these monochromatic light conditions.A notable observation is that the produced J ph values exhibit a strong dependency on the frequency or wavelength of the incident light.The optimal J ph value is achieved at a wavelength of 340 nm, where it reaches −4.2 mA•cm −2 .Subsequently, it is evident that 730 nm light has a more significant effect on the photocathode for hydrogen generation compared to 540 nm light, with J ph values of −3.5 and −2.2 mA•cm −2 , respectively.This behavior confirms the optical absorbance curve (Figure 4(a)), through which the wavelength at 730 nm has a much higher absorbance than 540 nm.These correlations are depicted in Figure 5(b) through the wavelength-produced current relationship at −0.85 V.
These data clearly illustrate that the prepared photocathode possesses a remarkable efficiency for generating hydrogen from sewage water across a wide range of optical regions, extending from the UV to the infrared (IR) regions.This exceptional performance can be attributed to the diverse compositions of the synthesized photocathode, encompassing MoS 3 , MoO 3 , and P1HP.These materials have been skillfully combined within the nanocomposite to facilitate light absorption and uniformly respond to photons spanning various optical regions.
By equation, E = hv, it is crucial to note that the energy of incident light at 340, 540, and 730 nm amounts to 3.6, 2.3, and 1.6 eV, respectively.Importantly, all of these energy levels surpass the nanocomposite's bandgap value of 1.4 eV.Moreover, all incident photons possess adequate energy to stimulate hot electrons and propel them into the conducting band.These electrons finally stay in the aqueous wastewater, where they facilitate the hydrogen generation reaction, ultimately contributing to the production of J ph .
The IPCE generated by the synthesized MoS 3 -MoO 3 / P1HP nanocomposite photocathode is meticulously calculated across a range of wavelengths, as illustrated in Figure 7(a) using Eq. 2 [40].This analysis reveals that the MoS 3 -MoO 3 / P1HP nanocomposite photocathode attains its peak IPCE at 340 nm, achieving an impressive efficiency of 12.66%.This efficiency is noteworthy for two key reasons: First, the hydrogen production process is conducted using sewage water as the source material.This approach effectively converts contaminants present in sewage water into a valuable source of renewable energy.The ability to harness energy from such a waste product underscores the environmental and sustainability benefits of this technology.
Second, the photocathode itself is constructed from a costeffective MoS 3 -MoO 3 /P1HP nanocomposite material supported on a glass slide.This cost-effective nature of the photocathode highlights the potential for large-scale and economically viable applications.Thus, this study demonstrates the production of highly efficient products through cost-effective techniques, further enhancing its practicality and relevance.
Figure 7(b) provides additional insight into this phenomenon by depicting the quantity of hydrogen molecules produced, which amounts to 1.2 moles•h −1 •cm −2 .These substantial hydrogen production figures serve as further evidence of the efficiency of the MoS 3 -MoO 3 /P1HP nanocomposite photocathode.The calculation of these quantities is accomplished through the application of the Nernstian equation, Eq. 3 [41].
So, the MoS 3 -MoO 3 /P1HP nanocomposite photocathode achieves an outstanding level of efficiency, as demonstrated by its peak IPCE of 12.66% at 340 nm.This efficiency is particularly remarkable due to the utilization of sewage water as the source of hydrogen production and the cost-effective composition of the photocathode.Furthermore, the significant quantities of hydrogen molecules produced underscore the effectiveness and practicality of this innovative technology The synthesized MoS 3 -MoO 3 /P1HP nanocomposite, shown in Figure 8, serves as a highly promising photocathode for H 2 generation using sewage water.This promin composite is related to the interaction of the MoS 3 -MoO 3 and P1HP during the polymerization reaction under the formation of coordination bonds.
The schematic mechanism provides a comprehensive overview of the nanocomposite's theoretical modeling and its photoactive nature.In the illustration, the nanocomposite exhibits rod-like structures with dimensions specified at 245 nm in length and 64 nm in width.Notably, the rod structure reveals a porous nature, indicative of the incorporation of inorganic materials MoS 3 -MoO 3 within the polymer network.This integration gives rise to distinct dark and faint regions within the nanocomposite.
Under light illumination, the photocatalytic properties of the material come into play.External level splitting occurs, initiating the generation of photogenerated  carriers, specifically electron-hole pairs.The electrons undergo accumulation on the surface of the P1HP, facilitated by their migration from the MoS 3 -MoO 3 materials, while the holes travel in the opposite direction.As the process unfolds, the hot electrons become attached to the wastewater, marking significant steps in the photocatalytic cycle [42,43].Ultimately, a series of reactions culminated in the production of H 2 gas.This multifaceted mechanism demonstrates the nanocomposite's efficiency in harnessing light energy to drive the photocatalytic generation of hydrogen from sewage water, offering a promising avenue for sustainable and environmentally friendly H 2 production.

Conclusions
The synthesis of rod-shaped MoS 3 -MoO 3 /P1HP involves a one-pot preparation method.In this process, the pyrrole monomer is oxidized using Na 2 MoO 4 as the oxidizing agent.This oxidation process is crucial for the integration of the inorganic components into the polymer matrix.The resulting material undergoes a comprehensive range of analyses, collectively providing a profound understanding of its properties.These investigations encompass an exploration of its chemical structure, crystalline characteristics, elemental composition, oxidation states, as well as its optical and electrical behavior.
One of the standout features of this material is its bandgap, which is optimally situated at 1.4 eV.This places it in a highly favorable position for its intended applications.Furthermore, its rod-like structure, with an average length of 400 nm and a width of 30 nm, enhances its appeal.In practical applications, the MoS 3 -MoO 3 /P1HP thin film serves as an exceptionally promising photoelectrode.Its primary strength lies in its ability to efficiently generate hydrogen from sewage water.It achieves an impressive efficiency rate of 12.66%, specifically at 340 nm.Additionally, it boasts an extraordinary hydrogen generation rate of 1.2 moles•h −1 •cm −2 .
The exceptional performance and unique properties of this composite material have prompted experts to recommend its adoption for hydrogen generation in industrial settings.Its efficiency and capability to produce hydrogen from wastewater make it a highly promising candidate for sustainable and environmentally friendly industrial applications.This breakthrough could pave the way for advancements in the field of hydrogen production, offering a cleaner and more efficient alternative to traditional methods.

Figure 2 (
Figure2(a) provides the FTIR transmittance spectra for both P1HP and MoS 3 -MoO 3 /P1HP, offering insights into their molecular compositions and characteristic peaks.Let us examine the primary peaks and their attributions in these spectra:In the spectrum of pyrrole (P1HP), absorptions are observed at 681 and 797 cm −1 related to the pare substituted P1HP ring.Prominent absorption peaks centered at 1,045 and 1,177 cm −1 are for the C-H bonds[20].The dominant absorption peak is located around 3,420 cm −1 for the N-H bonds present in the pyrrole amines[21].Peaks centered at 1,621 cm −1 are for C]C bonds within the molecular structure.A peak at 1,545 cm −1 can be assigned to the C]C stretching vibrations originating from the pyrrole rings.The peak appearing at 1,463 cm −1 is linked to the conjugated pyrrole C-N.An intermediate-intensity band at 1,312 cm −1 is for the valence vibrations of the pyrrole C-N bond[22].Overall, the observed FTIR spectrum is in excellent agreement with the proposed molecular structure of pyrrole.These characteristic peaks and their assignments confirm the presence of key functional groups and molecular bonds within the P1HP molecule.Furthermore, the FTIR spectrum

Figure 1 :
Figure 1: Three-electrode cell diagram used for the green hydrogen generation using the MoS 3 -MoO 3 /P1HP thin film photocathode for green H 2 production.

Figure 3 :
Figure 3: Morphology and topography of the synthesized nanomaterials: (a) SEM of P1HP, (b) SEM of MoS 3 -MoO 3 /P1HP, and (c and d) TEM of this nanocomposite.

Figure 5 :
Figure 5: Photoelectrochemical response of the MoS 3 -MoO 3 /P1HP nanocomposite photocathode (a) under darkness and light and (b) chopped on/off the light.

Figure 6 :
Figure 6: (a) Responsivity of the MoS 3 -MoO 3 /P1HP photocathode to different monochromatic light and (b) the estimated J ph value at −0.85 V.

Figure 7 :
Figure 7: (a) IPCE and (b) the hydrogen mole produced for the MoS 3 -MoO 3 /P1HP nanocomposite photocathode inside the three electrodes for green hydrogen generation.

Figure 8 :
Figure 8: Schematic mechanism for the synthesized MoS 3 -MoO 3 /P1HP photocathode for the hydrogen generation from wastewater (through the rodshaped particle) and mention the chemical formula of this nanocomposite.

Table 1 :
Compositions of the used wastewater for green hydrogen production