Preparation,characterization and electronic properties of LaFeO3 perovskite as photocatalyst for hydrogen production

Perovskite-type LaFeO₃ was successfully used as photocatalyst for the H₂ production. It was prepared by a conventional sol-gel technique via the nitrate route. X-Ray fluorescence/Energy Dispersive X-Ray fluorescence (XRF), X-Ray Diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), UV–Visible diffuse reflectance, FTIR spectroscopy, Scanning Electron Microscopy (SEM/EDX) and specific surface area were deployed to characterize the synthetized material after heat-treated at 850 °C. LaFeO₃ crystallizes in a cubic structure (Space Group: Pm3 m) with a crystallite size of 16 nm and BET surface area of 12 m²/g. Field-dependent magnetization was measured at 300 K in the region (±25 kOe) and the perovskite exhibits a high magnetism with a saturation magnetization (0.15 emu/g). Such result indicates that the Fe-3d are in localized high spin state. LaFeO₃ has a narrow band gap of 2.08 eV determined by diffuse reflectance resulting to the crystal field splitting of 3d orbital of Fe³⁺ octahedrally coordinated with an internal d-d transition. Cyclic voltammetry showed the reduction of adsorbed H₂O molecules to gaseous hydrogen at −0.7 V_SCE, a potential less cathodic than the conduction band (−0.45 V_SCE). The latter was determined from the capacitance measurements in alkaline electrolyte (NaOH 0.1 M) where the perovskite exhibits a stability with an exchange current density of ∼0.4 mA cm⁻². The photocatalytic activity reveals an optimal H₂ production of 99 μmol after 20 min at 50 °C in NaOH medium and a catalyst mass of 50 mg, under visible light irradiation (13 W) in the presence of thiosulfate S₂O₃²⁻ as hole scavenger.     

Elaboration and characterization of the brownmillerite Ca2Fe2O5 synthesized by citrate sol-gel method. Application for photocatalytic H2-Production under visible light over Ca2Fe2O5/ZnO hetero-system

The present work is devoted to the synthesis of the ferrite Ca₂Fe₂O₅ as photocatalyst crystallizing in the brownmillerite structure. The ternary oxide is prepared by sol-gel auto combustion and characterized by physical and electrochemical methods. The thermal analysis (TG/DSC) shows that, the formation of the brownmillerite is observed above 660 °C. The X-ray diffraction and BET analysis show respectively a single phase with an active surface area of ～6 m² g^?1. The SEM micrographs exhibit an inhomogeneous structure formed by agglomeration of irregular shaped grains, confirmed by the laser granulometry analysis. The forbidden band (～2.3 eV) determined from the diffuse reflectance, permits to explore ～ 30% of the sun spectrum into chemical energy. The p-type comportment of Ca₂Fe₂O₅ is demonstrated by the capacitance-potential (C^?2 - E) graph with a flat band potential (E_fb = 0.93 V_SCE), due to oxygen over-stoichiometry. The negative potential of the conduction band (?1.06 V_SCE) predicts the feasibility of the H₂ generation. Indeed, Ca₂Fe₂O₅ is chemical stable in a wide pH domain and is positively experimented as photocatalyst for the H₂-production under visible light. The best performance is obtained in alkaline medium (NaOH, 0.1 M) with a mean evolution rate of 18 μmol g^?1 min^?1. However, Ca₂Fe₂O₅ coupled to ZnO sol-gel (ZnO-SG) improves the catalytic performance. The H₂ evolution rate over (Ca₂Fe₂O₅/ZnO-SG) reached 24 μmol g^?1 min^?1 after 60 min. It has also been shown that ZnO–P, prepared by precipitation, is more efficient than that synthetized by sol-gel method (ZnO-SG) and TiO₂–P25.     

Preparation and characterization of α-Fe2O3 supported clay as a novel photocatalyst for hydrogen evolution

Improvement in the hydrogen evolution is reported over α-Fe₂O₃ supported on Algerian natural clay. The hetero-system is prepared by impregnation and calcination at 450 °C. It was characterized by X-ray diffraction, SEM analysis, FTIR spectroscopy and photo electrochemistry. The hematite Fe₂O₃ crystallizes in the corundum structure and exhibits n-type conductivity with a flat band potential of −0.88 V_SCE. Hence, the photo electrons located in Fe₂O₃-CB (−1 V_SCE) have high ability to reduce water into hydrogen. α-Fe₂O₃ gets effectively dispersed in the clay and the photoactivity increases with increasing its content. SO₃²⁻, working as hole scavenger, provides an absolute protection against the photo corrosion and favors the charges separation. The best performance of H₂ evolution occurs at alkaline pH on 10% Fe₂O₃/clay with a liberation rate 0.121 μmol/mg/min and a quantum efficiency of 1.2%.     

Elaboration,physical and photo-electrochemical properties of NiCr2O4. Application to hydrogen production under visible irradiation

The physical and photoelectrochemical characterization of NiCr₂O₄, prepared by sol gel route, were investigated to be applied for the H₂ production. The thermal gravimetry (TG) indicates that the single phase is formed above 530 °C as confirmed by X-ray diffraction (XRD). The Nano powder crystallizes in a tetragonal structure with lattice constants: a = 8.3276 Å and c = 8.5542 Å and a particle size of 63 nm, smaller than that obtained by Transmission Electronic Microscopy (TEM) analysis; the latter gives sizes between 80 and 150 nm, indicating crystallites agglomeration. The variation of the dielectric constant (ε) with temperature gives a relative value of 26 at 10 kHz. A direct optical transition at 1.79 eV is determined from the diffuse reflectance spectroscopy assigned to Cr³⁺ octahedrally coordinated. The thermal variation of the conductivity shows that 3d-electrons are localized and the data are modelled by a lattice-polaron hopping with an activation energy of 0.17 eV. The dependence of the interfacial capacitance on the potential (C⁻² - E) indicates p-type behavior with a flat band potential (E_fb) of −0.23 VSCE and holes density (N_A) of 5.88 × 10¹⁶ cm⁻³. The potential of the conduction band (−1.85 V_SCE) is below the H₂O/H₂ level (∼-1.2 V_SCE), allowing a spontaneous H₂-release under visible light. The O₂ evolution occurs at high over-voltage as shown from the intensity-potential (J-E) characteristic in Na₂SO₄ solution (0.1 M) and a hole scavenger was used to preclude the photo corrosion. The NiCr₂O₄ mass, pH and the hole scavenger (S₂O₃²⁻ and NO₂⁻) were optimized. The H₂ volume reached 65 μmol with an evolution rate of 8.6 μmol g⁻¹ min⁻¹, liberated under optimized conditions {1.2 g catalyst L⁻¹, pH ∼9 with thiosulfate S₂O₃²⁻ [10⁻³ M]}.     

Hydrogen evolution under visible light illumination on the solid solution CdxZn1-xS prepared by ultrasound-assisted route

The complete solid solution Cd_xZn_1-xS (0 ≤ x ≤ 1) prepared by ultrasound-assisted route is used for the H₂ formation upon visible light illumination. The correlation of chemical and physical characterizations permits to assess the feasibility of the system for the photocatalytic hydrogen evolution. The compounds crystallize in a cubic structure (x < 0.5) and convert to hexagonal variety above 0.5 with a crystallite size (8–17 nm). All materials exhibit n-type conduction with an activation energy (0.22–0.05 eV). The optical transitions are directly allowed (3.10–2.30 eV) and appropriately matched to the sun spectrum while the conduction band, deriving from (Zn, Cd) ns orbital (∼-1 V_SCE), is positioned above the H₂O/H₂ potential (∼-0.68 V_SCE), allowing H₂-liberation under visible illumination. The photocatalyst dose, pH and SO₃²⁻ concentration are optimized. Under the favorable conditions, the H₂ liberation rate reaches 12 × 10⁻⁴ mL mg⁻¹ min⁻¹ with a quantum yield η(H₂) of 1.40%.     

Opto-electrochemical characteristics of synthesized BaFe2O4 nanocomposites: Photocatalytic degradation and hydrogen generation investigation

We report on this study the optical and photo-electrochemical properties of BaFe₂O₄ (BFO) nanoparticles and their role in photocatalytic degradation of an organic pollutant and hydrogen generation. The spinel BFO was synthesized by the sol-gel route and formed at 900 °C, the phase was identified by the X-ray diffraction (XRD) analysis, confirmed by the Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The morphology was investigated by scanning electron microscopy (SEM). The optical and dielectric properties of BFO were investigated by the photoluminescence (PL) and the diffuse reflectance spectrum (DRS); An optical gap of 2.10 eV was found. The cyclic voltammetry of BFO has shown promising outcomes in the generation of hydrogen under visible light with a potential of (～- 0.91 V_SCE). The electrochemical impedance spectroscopy (EIS) was also undertaken in the dark and under illumination. In order to support the results, we tested the activity of this spinel for the degradation of Rhodamine B (Rh B), 93% of Rh B was oxidized after 3 h with a quantum efficiency of 0.32% by the BFO/ZnO. The use of the new BFO/ZnO hetero-system by adding ZnO nanoparticles was performed to enhance the photocatalytic activity which generates radicals for the Rh B degradation and hydrogen liberation. The degradation radicals were determined by scavenger tests, both O₂^??and ^?OH were the main reactive species. Moreover, the stability of BFO/ZnO hetero-system was demonstrated for four consecutive cycles. Hence, the hetero-system was found to be an efficient photocatalyst for hydrogen generation by facilitation of the photo-electron transfer with the deference potential (E_red – E_ZnO–CB = ～0.14 V_SCE); This opens up new opportunities for hydrogen production as we can say that energy supply has a high priority in our time due to its importance.     

Ultrathin Ti-doped hematite photoanode by pyrolysis of ferrocene

Ultrathin Ti-doped α-Fe₂O₃ photoanode was prepared by a facile atmospheric pressure chemical vapor deposition method through pyrolysis of ferrocene at 450 °C on Ti foil. The as prepared ultrathin hematite thin film has a surface feature size of 70 × 30 nm and a thickness of 50 nm. The photocurrent of this ultrathin hematite photoanode prepared at 450 °C in 1 M NaOH reaches 900 μA/cm² at 0.6 V_SCE under AM 1.5G illumination. The superior performance to the thin films prepared on FTO glass was ascribed to the diffusion and doping of Ti⁴⁺ from the metal substrate during pyrolysis deposition of hematite on Ti substrate.     

Hydrogen production on the new hetero-system Pr2NiO4/SnO2 under visible light irradiation

The Pr₂NiO₄/SnO₂ heterojunction with a mass ratio equal to unity was tested with success for the hydrogen production under visible light irradiation. Pr₂NiO₄, prepared by nitrate route, crystallizes in a tetragonal symmetry with K₂NiF₄ type structure. The physical, electrical and photo-electrochemical characterizations are correlated to show the feasibility of Pr₂NiO₄ for the hydrogen formation under visible light. The enhanced hydrogen production activity is due to electron injection of activated conduction band Pr₂NiO₄-CB (−1.53 V_SCE) into SnO₂-CB (−0.87 V_SCE) which acts as an electron pump, resulting in better water reduction. The band gap of the semiconductor Pr₂NiO₄ is 1.81 eV with a direct optical transition. Pr₂NiO₄ acquired p type conductivity, due to oxygen insertion in the layered lattice with an activation energy of 0.09 eV. The flat band potential (E_fb, 0.18 V_SCE), very close to the photocurrent onset potential (0.13 V_SCE) and the density of the holes (N_A, 1.85 10²⁰ cm⁻³) were obtained from the Mott-Schottky characteristic. H₂ production rate of 24.3 μmol g⁻¹ min⁻¹ is obtained with a quantum yield of 1.45% within 30 min under optimal conditions (1 mg of catalyst/mL, pH ~12 and 50 °C) in presence of S₂O₂⁻³ as hole scavenger under visible light flux of 29 mW cm⁻².     

Physical and photo-electrochemical characterizations of α-Fe2O3. Application for hydrogen production

The optical, electrical and photo-electrochemical properties of dense hematite α-Fe₂O₃ have been studied for the photo-catalytic hydrogen production. The band gap was evaluated at 1.96 eV from the diffuse reflectance spectrum and the transition is directly allowed; further indirect transition occurs at 2.04 eV. The oxygen deficiency permits the altering of the transport properties and the oxide exhibits n type behavior with activation energy of 0.11 eV. α-Fe₂O₃ is found to be photo-electrochemically active. The flat band potential V_fb (−0.51 V_SCE) and the density N_D (19.12 × 10¹⁹ cm⁻³) were obtained respectively by extrapolating the linear part to C⁻² = 0 and the slope of the Mott–Schottky plot. The complex impedance pattern is circular in the high frequency region followed by a straight line in the low frequency one, a behavior attributed to the Warburg ionic diffusion. The conduction band edge (−0.62 V_SCE) lies below the H₂O/H₂ level (−0.50 V_SCE) and Fe₂O₃ offers the possibility to be used as hydrogen photocathode. The best activity was obtained in SO₃²⁻ (0.5 M, pH 13.8) solution with a rate evolution of 6 ml (g catalyst)⁻¹ min⁻¹.     

Photoelectrochemical properties of doped polyaniline: Application to hydrogen photoproduction

The semi conducting properties of doped polyaniline (emeraldine-salt, PANI) elaborated by chemical route are investigated by the photo-electrochemical technique. The band gap is found to be 1.48 eV and the transition is directly allowed. The electrical conduction obeys to an exponential law with activation energy of 0.13 eV. p-type conductivity is evidenced from the cathodic photocurrent. The energy band diagram clearly shows the spontaneous hydrogen photo evolution. The potential of the conduction band of PANI (−0.93 V_SCE) determined from the capacitance measurements is suitably positioned with respect to H₂O/H₂ level (−0.66 V_SCE). Therefore, the photocatalytic properties of this material has been evaluated according to the hydrogen generation. The best performance is achieved at pH ∼7 with a liberation rate of 0.113 mL h⁻¹ (mg catalyst)⁻¹ and a quantum efficiency of 0.18% under visible light (29 mW cm⁻²). An increase of 56% is obtained on the hetero-system PANI/TiO₂.     

Co complex modified on Eupergit C as a highly active catalyst for enhanced hydrogen production

In present paper, the preparation and catalytic activity of Eupergit C polymer (EC) modified Co complex was reported. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller Surface Area Analysis (BET), Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM) coupled with energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) were used to characterization of catalyst. EC modified-Co complex was the first time examined as a catalyst in NaBH₄ hydrolysis to H₂ evolution. The kinetic calculations were determined by using two different kinetic methods. The low activation energy barriers were achieved as 21.673 kJ mol^?1 for nth order model and as 21.061kJmol^?1 for Langmuir-Hinshelwood (L-H) model at low temperatures. EC modified-Co complex catalyst exhibited high performance with H₂ evolution rates of 3914 mL H₂g_cat^?1min^?1 and 9183 mLH₂g_cat^?1min^?1 at 30 °C–50 °C. Additionally, Langmuir–Hinshelwood mechanism was explained for EC modified Co complex catalyzed sodium borohydride hydrolysis reaction. The reusability experiments showed that EC modified-Co complex catalyst maintained excellent stability with 100% conversion and without significant lost after the 6th run.     

Fe2O3/spinel NiFe2O4 heterojunctions in-situ wrapped by one-dimensional porous carbon nanofibers for boosting oxygen evolution/reduction reactions

One-dimensional (1D) nanofiber structure of electrocatalyst has attracted increasing attention in oxygen evolution/reduction reactions (OER/ORR) owing to its unique structural properties. Here, MIL-53(Fe) and Ni(NO₃)₂·6H₂O are incorporated into the electrospun carbon nanofibers (CNFs) to prepare the nickel-iron spinel-based catalysts (Fe₂O₃/NiFe₂O₄@CNFs) with 1D and porous structure. The marked Fe₂O₃/NiFe₂O₄@CNFs-2 catalyst has a tube diameter of approximately 300 nm, a high surface area of 282.4 m² g^?1 and a hydrophilic surface (contact angle of 16.5°), which obtains a promising bifunctional activity with ΔE = 0.74 V (E_1/2 = 0.84 V (ORR) and E_j10 = 1.58 V (OER)) in alkaline media. Fe₂O₃/NiFe₂O₄@CNFs-2 has a higher catalytic stability (93.35%) than Pt/C (89.36%) for 30,000 s tests via an efficient 4e^? ORR pathway. For OER, Fe₂O₃/NiFe₂O₄@CNFs-2 obtains a low overpotential of 350 mV and a high Faraday efficiency of 92.7%. NiFe₂O₄ (Ni²⁺ in tetrahedral position) relies on its variable valence states (NiOOH and/or FeOOH) to obtain good catalytic activity and stability for OER, while CNFs wrap/protect the active components (Fe–N and graphic N) in the carbon skeleton to effectively improve the charge transfer (conductivity), activity and stability for ORR. Porous 1D nanofiber structure provides abundant smooth pathways for mass transfer. It indicates that the bimetallic active substances can promote bifunctional activity by synergistically changing the oxide/spinel interface structure.     

Visible light induced hydrogen evolution on new hetero-system ZnFe2O4/SrTiO3

The physical properties and photoelectrochemical characterization of the spinel ZnFe₂O₄, elaborated by chemical route, have been investigated for the hydrogen production under visible light. The forbidden band is found to be 1.92 eV and the transition is indirectly allowed. The electrical conduction occurs by small polaron hopping with activation energy of 0.20 eV. p-type conductivity is evidenced from positive thermopower and cathodic photocurrent. The flat band potential (0.18 V_SCE) determined from the capacitance measurements is suitably positioned with respect to H₂O/H₂ level (−0.85 V_SCE). Hence, ZnFe₂O₄ is found to be an efficient photocatalyst for hydrogen generation under visible light. The photoactivity increases significantly when the spinel is combined with a wide band gap semiconductor. The best performance with a hydrogen rate evolution of 9.2 cm³ h⁻¹ (mg catalyst)⁻¹ occurs over the new hetero-system ZnFe₂O₄/SrTiO₃ in Na₂S₂O₃ (0.025 M) solution.     

Photo-catalytic hydrogen production over Fe2O3 based catalysts

The hydrogen photo-evolution was successfully achieved in aqueous (Fe_1−xCr_x)₂O₃ suspensions (0 ≤ x ≤ 1). The solid solution has been prepared by incipient wetness impregnation and characterized by X-ray diffraction, BET, transport properties and photo-electrochemistry. The oxides crystallize in the corundum structure, they exhibit n-type conductivity with activation energy of ∼0.1 eV and the conduction occurs via adiabatic polaron hops. The characterization of the band edges has been studied by the Mott Schottky plots. The onset potential of the photo-current is ∼0.2 V cathodic with respect to the flat band potential, implying a small existence of surface states within the gap region. The absorption of visible light promotes electrons into (Fe_1−xCr_x)₂O₃-CB with a potential (∼−0.5 V_SCE) sufficient to reduce water into hydrogen. As expected, the quantum yield increases with decreasing the electro affinity through the substitution of iron by the more electropositive chromium which increases the band bending at the interface and favours the charge separation. The generated photo-voltage was sufficient to promote simultaneously H₂O reduction and SO₃²⁻ oxidation in the energetically downhill reaction (H₂O + SO₃²⁻ → H₂ + SO₄²⁻, ΔG = −17.68 kJ mol⁻¹). The best activity occurs over Fe_1.2Cr_0.8O₃ in SO₃²⁻ (0.1 M) solution with H₂ liberation rate of 21.7 μmol g⁻¹ min⁻¹ and a quantum yield 0.06% under polychromatic light. Over time, a pronounced deceleration occurs, due to the competitive reduction of the end product S₂O₆²⁻.     

KW-GO,a graphene-like carbon extracted from kitchen waste (KW) advances the hydrogen production of V2O5

In this paper, graphene-like carbon (KW-GO) extracted from kitchen waste (KW) is used to reduce the agglomeration of V₂O₅ and improve the separation rate of photogenerated electron-hole pairs from V₂O₅. We found that the V₂O₅-KW-GO composite material (VKW-GO) could significantly enhance the photocatalytic activity and H₂ production rate under visible light irradiation compared to pure V₂O₅. To analyze the composition and morphology of the materials, XRD, SEM, BET, UV–Vis, XPS, and Raman were measured. The results showed that the addition of KW-GO reduced the aggregation of V₂O₅ powder. At the same time, the specific surface area of the composite sample increased providing more active sites for photocatalytic hydrogen production. In addition, the visible absorption range of the composite sample also increased. As a result, the hydrogen production rate of V₂O₅ increased from 247.52 mol h^?1 g^?1 to 354.15 mol h^?1 g^?1. The method using V₂O₅ and VKW-GO as a catalyst for H₂ production is innovative, and the conclusion may provide important theoretical guidance for photocatalytic hydrogen production.     

Photocatalytic hydrogen evolution of nanoporous CoFe2O4 and NiFe2O4 for water splitting

The spinels CoFe₂O₄ and NiFe₂O₄ of nanoporous photocatalysts were prepared by dealloying and calcination. The photocatalytic performance for the hydrogen generation rate via water splitting was measured. The results revealed that CoFe₂O₄ exhibits a sheet-like nanoporous structure and that abundant mesopores are distributed in the nanosheets. NiFe₂O₄ shows a typical pore-ligament structure. The measurements show that hydrogen generation is exhibited by both oxides because the bandgap of CoFe₂O₄ and NiFe₂O₄ is higher than the water oxidization potential. The hydrogen generation rate is approximately 0.088 mmol h^?1g^?1 for CoFe₂O₄ and 0.026 mmol h^?1g^?1 for NiFe₂O₄ when the TEOA (10 vol%) sacrificial agent is adopted. This performance is significantly higher than that of methanol as the scavenger because TEOA increases the pH value of the solution, changes the negative shift in the conduction band energy level and improves the electron transport efficiency. The higher performance of CoFe₂O₄ is attributed to its larger specific surface area, ample unimpeded penetration diffusion paths and higher electron transfer rate.     

Sulphur and nitrogen-doped metal-free microalgal carbon catalysts for very active dehydrogenation of sodium borohydride in methanol

Micro algae based on Spirulina platensis is successfully used for the synthesis of S and N-doped metal-free carbon materials. The procedure consists of three stages; (i) Activated carbon production by KOH activation in CO₂ atmosphere (S-AC), (ii) S atom doping to the obtained S-AC using sulphuric acid by hydrothermal activation (S-AC-S), (iii) N atom doping by hydrothermal activation to S-AC obtained using nitric acid (S-AC-S-N). The S and N doped metal-free catalysts are used for H₂ release in NaBH₄ methanolysis reaction (NaBH₄-MR) for the first time. The metal-free carbon catalysts are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM-EDS), X-ray diffractometer spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption and elemental analysis (CHNS) methods. When the HGR values obtained for S-AC-S-N (26,000 mL min^?1 g^?1) and S-AC (2641 mL min^?1 g^?1) are compared, there is a 9.84-fold increase. Activation energy (Ea) value for S-AC-S-N was 10.59 kJ mol^?1.     

Water splitting for hydrogen production with ferrites

The water splitting reaction by a thermo-chemical cycle using ferrites was investigated for H₂ production. In the first step (activation step), ferrites were thermally reduced at 1200 °C to form an oxygen-deficient ferrite. In the second step (water splitting step), the activated ferrites were oxidized by water at 800 °C to produce hydrogen. Among the prepared ferrites, Ni-ferrite was found to be the most suitable for H₂ production. NiFe₂O₄ produced an average of 0.442 cm³/g cycle of H₂. The H₂ productivity of the Ni-ferrite was much higher than that of the other ferrites at the same temperature. XRD showed that the crystal structure of NiFe₂O₄ during the redox reaction was not changed during the repeated cycles, indicating that NiFe₂O₄ was an excellent material in terms of structural stability and durability.     

Enhanced hydrogen evolution reaction on highly stable titania‐supported PdO and Eu2O3 nanocomposites in a strong alkaline solution

In this work, PdO/TiO₂ and Eu₂O₃/TiO₂ nanocomposites (NCs) were synthesized using a new facile, template‐free, and one‐step solvothermal approach and characterized by several instrumentation techniques. X‐ray photoelectron spectroscopy studies revealed the presence of oxidized form of the Pd and Eu nanoparticles within the NC materials (PdO and Eu₂O₃). The two catalysts exhibited remarkable activity for the hydrogen evaluation reaction (HER) in a strong alkaline solution (4.0 M NaOH) with PdO/TiO₂ catalyst being the best, which recorded an exchange current density (j_o) of 0.26 mA cm^?2 and a Tafel slope (β_c) of 125 mV dec^?1. Such parameters are not far from those recorded for a commercial Pt/C catalyst (0.71 mA cm^?2 and 120 mV dec^?1) performed here under the same operating conditions. Eu₂O₃/TiO₂ catalyst recorded j_o and β_c values of 0.05 mA cm^?2 and 135 mV dec^?1. The Tafel slopes 125 and 135 mV dec^?1 calculated on the PdO/TiO₂ and Eu₂O₃/TiO₂ catalysts suggest a HER kinetics controlled by the Volmer step. PdO/TiO₂ catalyzed the HER with a high turnover frequency of 2.3 H₂/s at 0.2 V versus the reversible hydrogen electrode, while Eu₂O₃/TiO₂ catalyst only measured a turnover frequency value of 1.25 H₂/s at the same overpotential. The two catalysts exhibited excellent stability and durability after 10 000 cycles and 72 hours of controlled potential electrolysis at a high cathodic overpotential, reflecting their practical applicability. Scanning electron microscope and X‐ray photoelectron spectroscopy examinations revealed that the morphology and chemistry of both catalysts were not altered as a result of the performed long‐term stability and durability tests.