Facile synthesis of MoSe₂ embedded in La₂O₃ crystal for enhancing hydrogen evolution reaction

ABSTRACT

Molybdenum diselenide (MoSe₂) is a potential catalyst for the electrocatalytic hydrogen evolution reaction (HER). However, MoSe₂ exhibits a high overpotential in HER due to its low density of active sites, which may limit its practical applicability. Tuning the assisted metal interaction is an effective method for altering the atomic structure and catalytic efficiency of transition metal catalysts. Herein, we report a simple hydrothermal process for synthesising hybrid MoSe₂-La₂O₃ heterostructures for HER. The electrocatalytic HER of nanoflower MoSe₂ was improved in the presence of a supported lanthanide-oxide interaction (La₂O₃), proving that La₂O₃ materials produce additional activity sites in the MoSe₂ materials. The nanocomposite was drop-cast onto screen-printed carbon electrodes (SPCE) and showed reduced overpotential values compared to pristine MoSe₂ and La₂O₃ materials. Across all ratios tested, the MoSe₂-La₂O₃ (M-L2) nanocomposites with a molar ratio of 1:2 exhibit rapid charge transfer during HER performance, with a Tafel slope value of 66 mV/dec and an onsetpotential of 270 mV.

KEYWORDS:

• Molybdenum diselenide
• lanthanum oxide
• screen-printed carbon electrode
• hydrogen evolution reaction

1. Introduction

Hydrogen is considered one of the most likely replacements for fossil fuels in light of the depletion and pollution of traditional fossil fuels (Dresselhaus and Thomas 2001; Nicoletti et al. 2015; Sharma, Agarwal, and Jain 2021). An excellent and highly effective method to produce hydrogen is by electrocatalytic water-splitting process (Shinagawa and Takanabe 2017). When choosing a catalyst material for hydrogen evolution, it is essential to consider the efficiency of the electricity-to-hydrogen conversion (Laursen et al. 2012). Platinum (Pt) noble metals have been identified as the most efficient hydrogen evolution catalysts due to their almost negligible Gibbs free energy for hydrogen absorption (X. Liu et al. 2023; Yan et al. 2021; Zou and Zhang 2015). However, their limited availability and expensive price hinder their widespread application. Consequently, developing effective and economical catalysts that may substitute noble metals for HER is imperative to potentially lower the cost and increase the accessibility of hydrogen generation.

Recently, there has been considerable interest in developing a variety of Pt-free catalysts to lessen the Pt dependence of HER catalysts. Transition metal dichalcogenides (TMDC) have sparked a lot of interest as electrocatalysts due to their unusual structure, excellent electrochemical activity, and wide availability (Alahmadi et al. 2021; Ren et al. 2018). It is worth noting that all transition metal dichalcogenide crystals are composed of three layers held together by Van der Waals forces; the metal forms the core atom, while chalcogenide atoms (X) constitute the top and bottom layers. The chalcogenide atoms improve the electrical properties and structural stability of the crystals (Manzeli et al. 2017; Vikraman et al. 2018). Unlike other TMDC materials, molybdenum diselenide (MoSe₂) materials, which have two phases: 2H, a semiconductor, and IT, a metal, have attracted interest in research as HER electrocatalysts (Deng et al. 2019; Li et al. 2018). It is well known that electrocatalytic HER activity can be influenced by active sites, intrinsic activity, and conductivity. Typically, the basal plane of the majority of TMDC materials is rather inert, but the outer edges provide catalytically active sites (Wu et al. 2021). Additionally, due to the MoSe₂ nanoflakes having several inert basal planes, the electrochemical activity of these flacks is caused by unsaturated Se atoms at their edge positions (Masurkar, Thangavel, and Arava 2018; Tang et al. 2014). As a result, the electrocatalytic efficiency of MoSe₂ can be limited by its small number of active sites.

To address this critical issue, numerous attempts have been undertaken to increase electron delivery in the catalyst. By combining MoSe₂ with other materials such as highly conductive carbon materials graphene, carbon nanotubes, and gold, electron transport in the catalyst might be enhanced (Mabuea, Erasmus, and Swart 2023). Additionally, researchers have explored the use of doping techniques to improve the electron transport properties of MoSe₂ catalysts (Alahmadi and Aoun 2024). These techniques include introducing metallic or nonmetallic element dopants or creating defects in the MoSe₂ structure. The HER performance can be also enhanced by changing the growth conditions of MoSe₂, which results in the production of MoSe₂ nanosheets with specific structures and high active edge sites.

In the current study, a nanocomposite composed of MoSe₂ and La₂O₃ materials was produced using a simple one-step hydrothermal process to improve the HER activity of MoSe₂. These hybrid mixtures were evaluated as HER catalysts using a screen-printed carbon electrode. We believe that various interactions in the material, such as those between Mo and Se atoms and La₂O₃ component atoms, might lead to the development of additional catalytic sites, which are critical for improving the electrocatalytic performance of MoSe₂. With the inclusion of La₂O₃ components, MoSe₂ nanoflower structures may self-assemble into nanosheets, resulting in more active sites and, hence, increased electrochemical activity. Additionally, the investigation results demonstrated that M-L2 is much superior and more efficient than M-L1 and M-L3 for electrocatalytic HER performance. Similarly, the other electrocatalytic data studied at acidic conditions approved low charge transfer resistance and the high stability of M-L2. Several techniques were conducted to analyze the phase structure, composition, and morphology of the hybrid nanocomposite.

2. Experimental section

2.1. Material

Ammonium molybdate tetrahydrate ((NH₄)₆Mo₇O₂₄·4H₂O), lanthanum oxide (La₂O₃) and selenium (Se) were purchased from Sigma-Aldrich. The screen-printed carbon electrodes (SPCE) are obtained from Metrohm. Without additional purification, all chemicals were utilised simply as purchased.

2.2. Synthesis of the hybrid MoSe₂/La₂O₃ nanocomposite

The MoSe₂-La₂O₃ nanocomposite was synthesised in a single step using hydrothermal synthesis. This affordable approach aids in producing well-dispersed, scalable, and easy-to-handle nanomaterials. Figure 1 illustrates the procedure used for producing the MoSe₂/La₂O₃ heterogeneous structure. Briefly, 1 mmol of (NH₄)₆Mo₇O₂₄·4H₂O powdered was dissolved in 30 mL of distilled water. The same solution was subsequently supplemented with 2 mmol of selenium precursor (Se). Next, the mixture was agitated at room temperature for an hour to ensure homogeneity. To increase the limited number of active edge sites in MoSe₂ material, La₂O₃ has been selected to augment these sites at different concentrations. Thus, the same solution was mixed with varying amounts of commercial La₂O₃ (1, 2, and 3 mmol) and stirred for two hours to create a homogenous mixture. After the homogeneous mixture was placed into a 100 mL autoclave, it was heated for 24 hours to 200°C. After hydrothermal heating, the resulting mixture was cooled to the ambient temperature. The synthesised black precipitates were finally rinsed with distilled water and ethanol. Finally, the resultant nanocomposite was then dried for 6 hours. For comparison, the additional three MoSe₂/La₂O₃ heterojunctions were synthesised using the same method with mmole ratios of (NH₄)₆Mo₇O₂₄.4H₂O and La₂O₃ of 1:1 (denote as M-L1), 1:2 (denote as M-L2), and 1:3 (denote as M-L3). Additionally, the same processes were employed for producing pure MoSe₂ yet without the inclusion of La₂O₃.

Figure 1. Schematic illustration of MoSe₂/La₂O₃ heterostructure fabrication.

2.3. Characterisation

To investigate the phase composition of the obtained materials, X-ray powder diffraction (XRD) was carried out using a SHIMADZU-MAXima-XRD-7000 diffractometer that was outfitted with Cu-Ka radiation. The topographical structure of the materials was studied using a field emission scanning electron microscope (FESEM-JSM-IT700HR). To investigate the chemical component of the produced nanocomposites, a FESEM-JSM-IT700HR was also used to perform energy-dispersive X-ray (EDX) spectra and elemental mapping studies. Raman spectra of the prepared materials were recorded using Senterra at a wavelength of 532 nm laser excitation. Transmission electron microscopy (TEM) (QUANTA FEG 250) was involved to study the composite material. Details regarding elemental composition and their valence were obtained utilising an XPS Thermo Fisher Scientific, USA (with monochromatic X-ray Al K-Alpha radiation from 10 to 1350 eV and a spot size of 400 mm at a pressure of 10^–9 mbar).

2.4. Electrochemical measurements

Autolab (PGSTAT204) was used to conduct the electrochemistry measurements at room temperature. The disposable screen-printed carbon electrode (SPCE, Metrohm) is manufactured and constructed with a carbon serving as the counter electrode, an Ag/AgCl serving as the reference electrode, and a carbon serving as the working electrode. In all experiments, sulphuric acid (H₂SO₄, 0.5M) was used as the electrolyte. The equation E_RHE= E_Ag/AgCl + 0.1976 + 0.056 pH was applied in this work to determine the potentials with regard to the reversible hydrogen electrode. Next, 400 mg of catalytic material was dispersed in 3 mL of a 1:3 water-to-propanol solution. After that, the resultant suspension was ultrasonicated for at least an hour to produce a uniform solution. Subsequently, 2 µL of the slurry ink was delicately dropped casted onto the surface working electrode (4 mm diameter), followed by the addition of 2 µL of Nafion solution (5%). All experiment measurements were performed in an N₂-purge 0.5 M H₂SO₄ electrolyte at room temperature. Before assessing the electrocatalytic activity of the MoSe₂-La₂O₃ catalyst, many cyclic voltammetry (CV) cycles were performed. Linear sweep voltammetry (LSV) was conducted at a scan rate of 1 mV/s throughout a potential range of 0.2 to −0.8 V vs. RHE. The electrochemical impedance spectroscopy (EIS) experiment was performed using a constant 400 mV voltage and frequencies ranging from 100 kHz to 1 Hz.

3. Results and discussion

3.1. General characterisation of nanomaterials

X-ray powder diffraction (XRD) patterns in Figure 2(a) demonstrate the phase structure of the pristine La₂O₃ and MoSe₂ nanostructures, as well as the hybrid M-L2 nanostructure. The XRD peaks obtained from pristine La₂O₃ match the JCPDS data for La₂O₃ Card No. 04-0856 (Mustofa et al. 2020). The typical peaks at 2θ of 15.7, 27.3, 27.9, 39.5, and 48.7 relate to the La₂O₃ planes (100), (002), (101), (102), and (211), respectively (Wang et al. 2014). In the case of MoSe₂ material, all of the diffraction peaks observed in the XRD pattern of the produced MoSe₂ are perfectly aligned with the 2H-phase MoSe₂ (JCPDS Card No. 77-1715) (Yuan Liu, Zhu, and Chen 2015). The MoSe₂ phase planes (002), (100), (103), and (110) are indicated by prominent peaks at 13.3, 31.6, 37.5, and 56.4, respectively. For the mixed M-L2 sample, peak diffractions were observed for pristine La₂O₃ and MoSe₂. Raman spectroscopy was also utilised to examine the crystal structures of pure MoSe₂, pristine La₂O₃, and the M-L2 hybrid structures. The Raman spectra were recorded via a 532 nm laser excitation wavelength. The La₂O₃ material exhibits the typical Raman peak at 337 and 445 cm⁻¹, which matches to Eg_v1 vibration mode of the La-O, respectively (Bilel et al. 2021). In the resulting MoSe₂, a prominent Raman peak is observed at 240 cm⁻¹, corresponding to the out-of-plane mode (A_1g), which is consistent with earlier results (Markeev et al. 2021; Nayak et al. 2017). The hybrid M-L2 nanostructures (top spectrum in Figure 2(b)) contain the typical Raman peaks of MoSe₂ and La₂O₃. In fact, the Raman spectrum of the M-L2 composite structure has no extra peaks when compared to its constituents, La₂O₃ nanoparticles and MoSe₂ nanoflowers.

Figure 2. (a) XRD patterns; (b) Raman spectra of pure MoSe₂, La₂O₃, and hybrid M-L2.

FESEM was used to investigate the structure and morphology of pure MoSe₂, pristine La₂O₃, and M-L2 nanocomposite materials. Figure 3(a,b) show SEM images of pure La₂O₃ in the form of dense nanoparticles or nanocrystals with an inconsistent shape. These nanoparticles have a wide variety of sizes, which can reach several hundred nanometers. In contrast, microscopy images of pristine MoSe₂ at various magnifications are shown in Figure 3(c,d). Pristine MoSe₂ has the morphology of a microflowers-like structure with a large number of petals. Figure 3(e,f) demonstrate the unique nanosheet shape of the M-L2 nanocomposite. The rose-like structures of MoSe₂ are unaffected by the formation of the M-L2 nanocomposite, which has a more porous and opened structure with outstanding uniformity, indicating successful synthesis and formation of the nanocomposite. The nanosheet structure exhibits a high degree of uniformity in size and shape, indicating the high quality and crystallinity of the material. The edges of the nanosheets appear smooth and well defined. Furthermore, a significant number of edge nanosheets may provide a large number of active sites as well as a large specific surface area, which can boost electrocatalytic HER activity. The distribution and elemental composition of La, O, Mo, and Se were examined using energy dispersive spectroscopy (EDS) and element mapping. According to the EDS study shown in Figure 4(a), the atomic ratio of Mo:Se is estimated to be 1:2, which is about the same as the atomic ratio of MoSe₂. From Figure 4(c–f), elemental mapping images reveal that the W, Se, La, and O components were distributed consistently, indicating a homogeneous distribution of La₂O₃ in the MoSe₂ microflower structures. This leads to a close contact between MoSe₂ and La₂O₃, which promotes a synergistic impact of M-L2 during the electrocatalytic process and could boost catalytic HER performance. TEM and HRTEM images were obtained to investigate the crystal structure of the M-L2 catalyst (Figure 4(g–i)). The M-L2 HRTEM image reveals uniformly aligned lattice planes, which correspond to La₂O₃. Figure 4(i) shows an enlarged view of the lattice distances. The interplanar lattice spacing matches the [100] plane of La₂O₃.

Figure 3. FESEM images of produced products at different magnifications: (a, b) pristine La₂O₃, (c, d) Pure MoSe₂, and (e, f) M-L2 nanohybrid.

Figure 4. (a) EDX spectrum of the as prepared M-L2 sample. (b) SEM mage of elemental mapping. (c–f) EDX elemental mapping of La, O, Mo, and Se, respectively. (g) TEM image and (h and i) HRTEM along with magnified view of lattice plane of as prepared M-L2 sample.

The elemental composition and valence state of the MoSe₂, La₂O₃, and M-L2 nanohybrid surfaces were investigated using high-resolution X-ray photoelectron spectroscopy (XPS). Figure 5(a) demonstrates the entire scan spectra of the MoSe₂, La₂O₃, and M-L2 nanostructures. The XPS analysis of M-L2 revealed that La, O, Mo, and Se are the four primary elements detected in the synthesised materials, confirming the incorporation of these elements into the hybrid structure. The primary source of the C 1S signal at 284.6 eV is the carbon-conductive tape, which was employed for holding the sample during XPS measurements. Furthermore, the La 3d core level photoelectron spectra collected from pristine La₂O₃ nanoparticles and the M-L2 nanohybrid are depicted in Figure 5(b). The most prominent XPS peaks of elemental lanthanum are the La 3d_3/2 and La 3d_5/2 peaks, which are attributed to 851.6 and 834.78 eV, respectively (Agrawal et al. 2020; Sarkar et al. 2016). These peaks shifted by 0.3 eV to high-binding energy after being combined with MoSe₂, as shown in the M-L2 nanohybrid spectrum. Additionally, Figure 5(c) demonstrates the XPS spectrum of O 1s core level for La₂O₃ nanoparticles and M-L2 nanohybrid in which the binding energy at 530 eV is attributed to the La – O bond (Karthikeyan, Selvapandiyan, and Sankar 2022). Moreover, the XPS spectrum of Mo 3d derived from pure MoSe₂ and M-L2 nanohybrid displays four primary peaks, as shown in Figure 5(d). The oxidation state of Mo⁴⁺ is illustrated by two peaks at 228.6 and 231.7 eV, which agree to Mo 3d_5/2 and Mo 3d_3/2, respectively (Alahmadi and Sami 2023; J. Yang et al. 2016). In contrast to pristine MoSe₂, the electronic structure of MoSe₂ in the nanohybrid (M-L2 spectra) was changed, as demonstrated by the 0.8 eV shift of the Mo (IV) 3d_5/2 peak. Additionally, two peaks at 231.2 and 235.4 eV match Mo 3d_5/2 and Mo 3d_3/2, indicating the +6 valence state of Mo (Zhang et al. 2015). In the case of M-L2 spectrum, Mo (IV) 3d_5/2 binding energy shift by 0.8 eV. On the other hand, the hexavalent state peak at 235 is significantly pronounced in the M-L2 spectrum but is barely apparent in the pristine MoSe₂ spectrum. This peak could point to a stronger interaction of components in the M-L2 mixture. Similarly, Figure 5(e) shows the high-resolution XPS of Se 3d. The two identical peaks correspond to 3d5/2 (55 eV) and Se 3d3/2 (56.3 eV). This implies that the element selenium is in a −2 valence state (Tang et al. 2014; Vikraman et al. 2021). As indicated by Figure 5(e), the peaks (Se 3d_5/2 and Se 3d_3/2) in the M-L2 spectrum shift by 0.5 eV to low-binding energy, proving that the crystal structure of MoSe₂ in the nanohybrid has been changed. The findings support the successful production of the hybrid composite.

Figure 5. XPS results of pristine MoSe₂, La₂O₃, and an M-L2 nanocomposite sample. (a) Scan spectra for the three materials. High-resolution XPS spectra of (b) La 3d, (c) O 1s, (d) Mo 3d, and (e) Se 3d.

3.2. Electrocatalytic performance

In the following section, the electrochemical performance of bare and modified SPCE electrodes made from pristine MoSe₂ and pristine La₂O₃ are compared to that of modified SPCE electrodes formed from different nanocomposites (M-L1, M-L2, and M-L3). Besides, the electrochemical characteristics of Pt were employed as a control experiment. First, to verify the fabricated electrode activity, a few cyclic voltammetry (CV) cycles were performed before measuring HER performance in nitrogen-saturated 0.5 M H₂SO₄. First, the HER catalytic activity of as-fabricated nanocatalysts modified SPCE was examined using LSV at room temperature and a scan rate of 1 m/Vs as shown in Figure 6(a). The prepared catalysts are labelled as MoSe₂/SPCE, La₂O₃/SPCE, M-L1/SPCE, M-L2/SPCE and M-L3/SPCE. In acid electrolytes, MoSe₂/SPCE and La₂O₃/SPCE materials do not display significant catalytic activity for HER. The effect of varying the La₂O₃ catalyst's precursor concentration on MoSe₂ activity was investigated. When the molar ratio of La₂O₃ is raised from 1 to 2 mmol, the M-L2/SPCE electrode exhibits enhanced current density and a decreased overpotential (Figure 6(a)), indicating improved HER activity. The M-L2/SPCE hybrid exhibited the highest HER catalytic activity with a current density of 10 mA cm⁻² at an overpotential of around 400 mV. The presence of active sites generated by metal oxides at Mo and Se atoms may improve the nanocomposite's catalytic activity. However, the polarisation curve and overpotential show a reduction in activity after adding 3 mmol of La₂O₃ (M-L3) catalysts. Noteworthy is the fact that the amount of precursor used can significantly alter the phases of nanostructures, resulting in reduced overpotential and Rct. This indicates that selecting appropriate precursor concentrations can improve the catalytic performance in HER applications. Table 1 shows that MoSe₂/La₂O₃ exhibits better HER activity than previously described TMDC MoSe₂-based catalysts. It has long been recognised that the quantity of catalyst on the supporting electrode influences the performance of HER. Additionally, according to a recent study, Tafel slopes are strongly reliant on catalyst mass and fluctuate with the mass loading (Anantharaj and Kundu 2019).

Figure 6. (a) LSV polarisation curves. (b) The corresponding Tafel plots obtained from polarisation curves for the bare carbon, MoSe₂, La₂O₃, M-L1, M-L2 and M-L3.

Table 1. A comparison of HER catalytic performance of MoSe₂ materials.

Materials	Supporting Electrode	Loading (mg cm^−2)	Electrolyte	Tafel slope (mV/dec)	Ref.
Porous MoSe2	GC	0.4	0.5M H2SO4	80	Lei, Xu, and Wu (2016)
MoSe2/CC-30	GC	0.15 µm (th)	0.5M H2SO4	76	Yundan Liu et al. (2016)
MoSe2/CC-180	GC	3.2 µm (th)	0.5M H2SO4	102
Porous MoSe2	SPCE	1.11	0.5M H2SO4	56	Tran, Poorahong, and Siaj 2017)
MoSe2/CoMoSe	GC	1.8 nm (th)	0.5M H2SO4	95.2	Chen et al. (2017)
Boron-2H MoSe2	GC	0.64	0.5M H2SO4	72.4	Z. Mao et al. (2020)
MoSe2/WS2 (MW22)	GC	0.28	0.5M H2SO4	150	Hwang and Shin (2021)
NiSe2/MoSe2 HTs	GC	0.57	1M KOH	82	Dai et al. (2022)
MoSe2/La2O3	SPC	0.2	0.5M H2SO4	66	This work

* Key: GC: glassy carbon; Th: thickness; SPCE: screen-printed carbon electrode.

The Tafel slope of each electrocatalyst is illustrated in Figure 6(b). The Tafel equation (k = b log (j) + a) can be applied to derive Tafel slopes, where g is the overpotential, b is the Tafel slope, and j is the current density. MoSe₂, having Tafel slopes of 160 mV/dec, is a more potent HER catalyst than pristine La₂O₃ and bare carbon, which possessed Tafel slopes of 171 and 198 mV/dec, respectively. The hybrid M-L2 nanocomposite has a superior catalytic response as compared to its predecessors, with a value of 66.8 mV/dec. The synergistic impact of integrating different material components (MoSe₂ and La₂O₃) may be responsible for the improved HER efficiency and water-splitting ability of nanocomposite materials. As a result, the nanocomposites have higher HER activity compared to their pure components. Based on the lowest Tafel slope value across electrocatalysts, the electrochemical desorption process is expected to be the limiting step for M-L2/SPCE. We may deduce from the Tafel slope values that La₂O₃ is a promising catalyst for improving HER performance. Additionally, our M-L2@SPCE combination exhibits better electrocatalytic activity and more efficient charge transfer kinetics than other MoSe₂ materials previously examined, including tube-like MoSe₂/CoSe₂ microcages (73 mV/dec) (Mu et al. 2016), hetero-dimensional hybrid MoSe₂ (72 mV/dec) (B. Mao et al. 2017), and Ni-doped MoSe₂ (83 mV/dec) (Y. Yang et al. 2020).

To determine the electrical resistance of the catalysts, further investigation was conducted on the as-synthesis materials MoSe₂, La₂O₃, M-L1, M-L2, and M-L3 using electrochemical impedance spectroscopy (EIS). All electrocatalysts were measured using EIS in 0.5 M H₂SO₄. Figure 7(a) depicts the Nyquist plots produced from EIS measurements for all nanocatalysts modified SPCE. The diameter of a semicircle was utilised to calculate the catalyst charge transfer resistance R_(ct). Among all samples, M-L2/SPCE sample exhibits the lowest R_ct (∼250 Ω) and the highest electrical conductivity, indicating that electrons are moving rapidly across the electrocatalyst-electrolyte interface. The EIS data supports the earlier results that M-L2 was the most effective electrocatalyst for the HER since it showed a rapid rate of reaction. Furthermore, durability is a significant factor to consider when evaluating electrocatalytic HER performance, whether the catalyst will be used for industrial or commercial uses. The long-term stability of the optimised electrode towards HER was assessed by testing ideal catalysts (M-L2/SPCE) over 1000 CV cycles in 0.5 M H₂SO₄, as shown in Figure 7(b). This result suggests that the M-L2 catalyst demonstrated stability during HER performance. With a slight drop in the M-L2 electrocatalyst's catalytic activity, this data implies that the M-L2 catalyst is durable during HER performance. It is likely that during the HER event, the hybrid M-L2 mixture delaminated from the SPCE's surface, leading to the observed drop in HER catalytic activity (Benck et al. 2012).

Figure 7. (a) Electrochemical impedance spectra of the bare carbon, MoSe₂, La₂O₃, M-L1, M-L2 and M-L3. (b) Stability results for the M-L2 sample before and after 1000 CV cycles in 0.5 M H₂SO₄ under N₂ atmosphere_.

4. Conclusion

In conclusion, a hybrid nanocomposite of MoSe₂-La₂O₃ with high catalytic activity toward HER can be prepared using one-step hydrothermal techniques. Metal oxide (La₂O₃) has significantly improved MoSe₂ HER performance by increasing the possibility of H⁺ adsorption at active edge sites. It has been proven that a small quantity of La₂O₃ is critical for increasing the activity of MoSe₂ even though La₂O₃ and MoSe₂ alone have low activity. In acidic conditions, among several developed nanocomposites, the M-L2 nanocomposite sample demonstrates considerably better electrocatalytic capabilities for HER, with a low overpotential of around 400 mV at 10 mA/cm², which is significantly lower than that of the pure MoSe₂. Finally, these catalysts are stable, making them excellent for electrocatalytic hydrogen production.

Disclosure statement

No potential conflict of interest was reported by the author(s).