Decoration of plasmonic Cu nanoparticles on WO3/Bi2S3 QDs heterojunction for enhanced photoelectrochemical water splitting

We report a WO₃/Cu/Bi₂S₃ wherein incorporation of Cu nanoparticles (Cu NPs) to enhance the photoelectrochemical activity over WO₃/Bi₂S₃. Cu NPs effectively harvest the light energy upon plasmon excitation and transfer the energy to contacted WO₃, thereby improving the photoelectrochemical (PEC) performance. The WO₃/Cu/Bi₂S₃ composite was characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray diffraction (XRD) to analyze the morphology and interfacial contact between the semiconductors. The photocurrent density and Solar-to-Hydrogen conversion efficiency for this composite is 10.6 mA cm⁻² at 1.23 V (versus RHE) and 3.21% at 0.81 V (versus RHE), which are much higher than WO₃/Bi₂S₃ with 4.02 mA cm⁻² at 1.23 V (versus RHE) and 2.46% at 0.81 V (versus RHE) respectively. Moreover, the stability and photo-response of WO₃/Cu/Bi₂S₃ were carried out through chronoamperometric studies. The composite retained its stability over 50 cycles without decay in PEC performance. High incident photon conversion efficiency (IPCE) value of about 51% is achieved which is evident from the high photocurrent density. Incorporation of Cu NPs increase the photoactivity which is evident from the photocurrent value. The increased activity of Cu NPs sandwiched composite is attributed for the quick electron transfer to semiconductor due to surface plasmon resonance (SPR) effect.     

Combustion synthesis of copper ceria solid solution for CO2 conversion to CO via reverse water gas shift reaction

The reverse water–gas shift chemical (RWGS) reaction is a promising technique of converting CO₂ to CO at low operating temperatures, with high CO selectivity and negligible side products. In this study, we investigate the synthesis of Cu/CeO₂ catalyst using Solution Combustion Synthesis (SCS) technique and its performance for the RWGS reaction using a tubular packed bed reactor. Results indicate that the catalytic activity and stability of CeO₂ at low and moderate temperatures can be effectively improved by the addition of a small quantity of copper (1 wt%). The conversion of CO₂ improves with an increase in temperature, with a maximum value of 70% at 600 °C, showing a steady time on stream (TOS) performance for 1200 min with negligible carbon deposition of <0.05 wt%. The high catalyst activity is due to the synergistic interaction between the active Cu⁰ species and Ce³⁺-oxygen vacancy. The Cu/CeO₂ catalyst was also found to have 100% selectivity for CO, and no CH₄ was detected in the outlet stream. Moreover, the morphological characteristics of the support and catalysts (fresh and post-reaction samples), as well as the impact of reaction on the catalysts surface were investigated using various methods such as x-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy with energy dispersive x-ray spectra (SEM/EDX). The results demonstrate that Cu/CeO₂ offers a good potential for being a robust RWGS catalyst with exclusive selectivity for CO without the undesired methanation side-reaction.     

Photoelectrochemical performance of Cu-doped ZnIn2S4 electrodes created using chemical bath deposition

A solution growth method for the deposition of Cu-doped zinc-indium-sulfide (ZnIn₂S₄) semiconductor film electrodes is presented. The structural, optical, and photoelectrochemical (PEC) properties of samples were studied as a function of Cu content in samples. The X-ray diffraction pattern of the cubic ZnIn₂S₄ phase of an undoped sample was obtained. No Cu alloys or other binary compounds that included the Cu element were present in Cu-doped ZnIn₂S₄ samples. Images from a scanning electron microscope and atomic ratios of elements in samples obtained from the energy dispersion analysis of X-ray reveal a change in surface morphology and composition for Cu-doped ZnIn₂S₄ samples. The direct energy band gaps, indirect energy band gaps, and thicknesses of samples prepared in this study varied in the ranges 2.07-2.58 eV, 1.60-2.06 eV, and 521-879 nm, respectively. The maximum photoelectrochemical response of samples in 0.5 M K₂SO₄ aqueous solution reached 1.15 mA cm⁻² at an external potential of +1.0 V vs. an Ag/AgCl reference electrode under illumination using a 300-W Xe lamp with light intensity kept at 100 mW cm⁻². The experimental results show that Cu doping with Cu/(Cu+Zn) atomic ratio of 0.08 in samples improves the performance of the ZnIn₂S₄ photoabsorber for PEC applications.     

Cu doped Ni–Co spinel protective coatings for solid oxide fuel cell interconnects application

Four different amount of Cu doped Ni–Co alloy coatings were fabricated on SUS430 substrate by electroplating for solid oxide fuel cells (SOFCs) interconnects application. After oxidation at 800 °C, the microstructure and oxide phase of samples were tested by scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Our experimental results indicated that the Cu addition improved the electrical behavior of Ni–Co alloy coating. Cu doping reduced the activation energy (Ea) of electrons hopping and inhibited the growth of Cr₂O₃ oxide layer. Furthermore, the oxidation kinetics and electrical properties of the alloy coatings were obtained. These results showed that the 9% Cu doped Ni–Co coated steels achieved the minimum parabolic rate constant (2.05 × 10⁻¹⁴ g²cm⁻⁴s⁻¹) and area specific resistance (14.11 mΩ cm²) after the thermostatic oxidation process.     

Photoelectrochemical water splitting with 600 keV N2+ ion irradiated BiVO4 and BiVO4/Au photoanodes

Low energy N²⁺ ion beam with 600 keV energy has been used to irradiate BiVO₄ and Au nanoparticles loaded BiVO₄ (BiVO₄/Au) thin films deposited over fluorine doped tin oxide substrates via spray pyrolysis technique. Ion irradiation results in tailoring the optical, electrical, and morphological properties of the thin films and thence also responsible for changes in electrochemical properties. The scanning electron microscope images reveal the evolution of Au nanoparticles after irradiation at 2 × 10¹⁵ fluence to a nanourchins type of morphology. In consequence of morphological changes, the signature of surface plasmon resonance peak exhibited by Au nanoparticles in BiVO₄/Au shows improvement. An increase of approximately 92% in photocurrent density in comparison to pristine BiVO₄ has been found after irradiation in BiVO₄/Au photoanode at 2 × 10¹⁵ ions/cm² fluence. Moreover, irradiation also aids in improving photoelectrochemical response of BiVO₄ photoanodes without Au nanoparticles. The enhancement can be attributed to the notable changes in onset potential, charge separation, charge transfer resistance and optical properties.     

Photocatalytic hydrogen evolution from water splitting using Cu doped ZnS microspheres under visible light irradiation

Cu/ZnS microspheres have been successfully synthesized using microwave irradiation method without using any template. Cu/ZnS microspheres were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), inductively coupled plasma optima optical emission spectrometer (ICP-OES), X-ray photoelectron spectroscopy (XPS), diffused reflectance spectroscopy (DRS), and electrochemical impedance spectroscopy (EIS) methods. Tuning of band gap from 3.43 to 2.36 eV was successfully achieved upon doping copper (0–10%) into ZnS. The photocatalytic activity was investigated by photosplitting of water containing an aqueous Na₂S solution under visible light irradiation. Among the prepared photocatalysts, the hydrogen evolution rate reaches the maximum of about 973.1 μmol h⁻¹ g⁻¹ for 2.0 mol% Cu²⁺ ion doped ZnS. Moreover, Cu/ZnS microspheres were found photocatalytically stable during the 48 h test runs.     

Electrical and optical properties of Cu2ZnSnS4 thin films prepared by rf magnetron sputtering process

Cu₂ZnSnS₄ thin films were deposited on corning 7059 glass substrates without substrates heating by rf magnetron sputtering. The Cu/(Zn+Sn) ratio of the thin film sputtered at 75 W was close to the stoichiometry of Cu₂ZnSnS₄. However, the S/(Cu+Zn+Sn) ratio was less than the stoichiometry. The as-deposited films were amorphous and annealed in the atmosphere of Ar+S₂ (g). The annealed (1 1 2), (2 0 0), (2 2 0), (3 1 2) planes were conformed to all the reflection of a kesterite structure. A preferred (1 1 2) orientation was observed with the increase of the annealing temperature. The optical absorption coefficient of the thin film was about 1.0×10⁴ cm⁻¹. The optical band energy was derived to be 1.51 eV. The optical absorption coefficient of the sputtered Cu₂ZnSnS₄ thin films was less than that of CuInS₂ thin film, however, the band gap energy was more appropriate for photovoltaic materials.     

Vacuum-assisted electroless copper plating on Ni/(Sm,Ce)O2 anodes for intermediate temperature solid oxide fuel cells

Cu is incorporated by vacuum-assisted electroless plating into porous Ni/Sm_0.2Ce_0.8O_1.9 (Ni/SDC) anodes as the active anodes for the oxidation reaction of hydrogen and methane of intermediate temperature solid oxide fuel cells (IT-SOFCs). The scanning electron microscopy (SEM) observation indicates the formation of a uniformly distributed nano-structured Cu network within the porous Ni/SDC microstructure. The maximum power density of the cell with the Cu electroless-plated Ni/SDC anodes is 0.84 and 0.54 W cm⁻² in dry H₂ and dry CH₄ at 600 °C, respectively, enhanced by ∼30% as compared to the cell with conventional Ni/SDC anodes. The increase in the performance of the cell with the Cu electroless-plated Ni/SDC anodes is most likely attributed to the enlarged effective three-phase boundaries (TPBs) by interconnecting the isolated Ni and/or SDC particles with the electroless-plated Cu network and the formation of TPBs at the Cu/SDC interface due to the activation of SDC surface by the Cu deposition. The stability test shows that cell degradation in dry methane due to carbon deposition is significantly reduced by the electroless copper plating.     

Investigation of pulsed non-melt laser annealing on the film properties and performance of Cu(In,Ga)Se2 solar cells

Pulsed non-melt laser annealing (NLA) has been used for the first time to modify near-surface defects and related junction properties in Cu(In,Ga)Se₂ (CIGS) solar cells. CIGS films deposited on Mo/glass substrates were annealed using a 25 ns pulsed 248 nm laser beam at selected laser energy density in the range 20–60 mJ/cm² and pulse number in the range 5–20 pulses. XRD peak narrowing and SEM surface feature size increase suggest near-surface structure changes. Dual-beam optical modulation (DBOM) and Hall-effect measurements indicate NLA treatment increases the effective carrier lifetime and mobility along with the sheet resistance. In addition, several annealed CdS/CIGS films processed by NLA were fabricated into solar cells and characterized by photo- and dark-J–V and quantum efficiency (QE) measurements. The results show significant improvement in the overall cell performance when compared to unannealed cells. The results suggest that an optimal NLA energy density and pulse number for a 25 ns pulse width are approximately 30 mJ/cm² and 5 pulses, respectively. The NLA results reveal that overall cell efficiency of a cell processed from an unannealed film increased from 7.69% to 13.41% and 12.22% after annealing 2 different samples at the best condition prior to device processing.     

High performance Ni exsolved and Cu added La0.8Ce0.2Mn0.6Ni0.4O3-based perovskites for ethanol steam reforming

La_0.8Ce_0.2Mn_0.6Ni_0.4O₃ with (LCMN@CuO) and without (LCMN) CuO addition are prepared by solution methods, followed by reduction in 5% H₂–N₂ stream at 650 °C to form Ni exsolved and CuO reduced catalysts, LCMN@Ni and LCMN@Ni/Cu, for ethanol (EtOH) steam reforming (ESR). The catalysts are characterized by X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), temperature programmed reduction (H₂-TPR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy etc., and are evaluated for ESR with a steam/carbon ratio of 3 and a weight hourly space velocity (WHSV) of 4 h⁻¹ at temperatures between 500 and 700 °C. Ni exsolution and CuO reduction are confirmed on the substrates in LCMN@Ni and LCMN@Ni/Cu. Both the catalysts demonstrate a complete conversion of EtOH, forming mainly H₂, CO₂, CO and CH₄. And increasing temperature to 700 °C increases the yields of H₂ and CO to the levels about 90% and 40%, respectively, at the cost of CH₄; and such performance remains unchanged for 30 h. These results indicate that both LCMN@Ni and LCMN@Ni/Cu are promising catalysts for ESR, the main difference between them is that the latter is more chemically stable and more resistant to carbon deposition under ESR conditions.     

Low-temperature CO preferential oxidation in H2-rich stream over iron modified Pd–Cu/hydroxyapatite catalyst

The effect of FeCl₃ addition on the catalytic property of Pd–Cu/hydroxyapatite (Pd–Cu/HAP) for low-temperature CO preferential oxidation (CO-PROX) under H₂-rich condition has been investigated. It can be found that CO conversion of Pd–Cu/HAP rapidly decreases from 56% to 21% within 2 h at 30 °C in the presence of water, however, the Pd–Cu–Fe/HAP with the Fe/Cu atomic ratio of 1:1 presents a stable CO conversion of 40% and CO₂ selectivity of 100% under the same reaction conditions. The characterization results display that the addition of FeCl₃ to Pd–Cu/HAP causes the formation of Fe₂O₃ species, and the strong interaction presents between Fe₂O₃ species and Pd–Cu/HAP. Thus, the Pd⁰ species generated during CO-PROX over Pd–Cu–Fe/HAP can be more easily oxidized than that over Pd–Cu/HAP, which could avoid H₂ adsorption on Pd⁰ species and maintain CO adsorption and activation.     

Physicochemical properties and electrochemical hydrogen storage performance of Li2M(WO4)2 (M = Co,Ni and Cu)

In this work, new materials of the Li₂M(WO₄)₂ type with (M = Co, Ni and Cu) have been studied for the first time as electrodes for electrochemical hydrogen storage. The three double tungstates compounds, have been synthesized by a one-step solid-state reaction and carefully characterized, using X-ray diffraction, scanning electron microscopy, UV–visible and FTIR spectroscopy. The presence of a pure and single phase is confirmed by XRD with the Rietveld refinement for all the studied materials, while SEM observation reveals the granular microstructure of these compounds (1-10 μm). Very close energy gaps of 1.60 eV, 1.62 eV and 1.64 eV are respectively attributed to Li₂Cu(WO₄)₂, Li₂Co(WO₄)₂ and Li₂Ni(WO₄)₂. Cyclic voltametry shows the characteristic redox peaks of these samples and clearly elucidates the redox behavior of the battery type. EIS results show good contact between the surface of the studied materials and the H₂SO₄ electrolyte, with a surface resistance of (~2 Ω/cm²). The charge-discharge galvanostatic cycling gives a specific storage capacity of 120.1 mA h.g⁻¹ Li₂Ni(WO₄)₂, 98.88 mA h.g⁻¹ Li₂Co(WO₄)₂ and 84.44 mA h.g⁻¹ Li₂Cu(WO₄)₂ at 1 A g⁻¹. They also exhibit a good life cycle stability that exceeds 84%–90% of the retention capacity of Li₂Ni(WO₄)₂ after 50 cycles at 1 A g⁻¹.     

Effective MgO‐doped TiO2 nanoaerogel coating for crystalline silicon solar cells improvement

This study looks at investigating the influence of high surface area TiO₂ and MgO‐doped TiO₂ aerogel nanomaterials to improve the photovoltaic performance of monocrystalline silicon (mono‐Si) solar cells. TiO₂ and MgO‐doped TiO₂ anatase nanoaerogels were synthesized via a single‐step colloidal homogeneous precipitation sol‐gel method in a compact high‐pressure hydrogen reactor. TiO₂‐based nanoparticles were encapsulated in ethylene vinyl acetate resins, and the obtained composite solutions were screen printed on the textured surface of the cells. The specific surface area, microstructural, composition, and optical properties of the nanoaerogels were characterized by Brunaur‐Emmett‐Teller, X‐ray powder diffractometer, energy‐dispersive X‐ray spectroscopy, field emission transmission electron microscope, field emission scanning electron microscope, and ultraviolet‐visible spectrophotometry. We observed that the MgO‐doped TiO₂ (2% mol) nanoaerogel exhibited a much superior specific surface area (231 m²/g) compared with the undoped TiO₂ (154 m²/g). Experimental results showed that the calculated relative power conversion efficiency increased by 4.6% for the MgO‐doped TiO₂ coating and 3.4% for the undoped TiO₂ under a simulated one‐sun illumination.     

Studies on Cu2ZnSnS4 (CZTS) absorber layer using different stacking orders in precursor thin films

Cu₂ZnSnS₄ (CZTS) thin films were deposited by sputtering on glass substrates using stacked precursors. The stacked precursor thin films were prepared from Cu, SnS₂ and ZnS targets at room temperature with different stacking orders of Cu/SnS₂/ZnS/glass (A), ZnS/Cu/SnS₂/glass (B) and SnS₂/ZnS/Cu/glass (C). The stacked precursor thin films were sulfurized using a tubular rapid thermal annealing system in a mixed N₂ (95%)+H₂S (5%) atmosphere at 550 °C for 10 min. The effects of the stacking order in the precursor thin films on the structural, morphological, chemical, electrical and optical properties of the CZTS thin films were investigated. X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy studies showed that the annealed CZTS thin film using a stacking order A had a single kesterite crystal structure without secondary phases, whereas stacking orders B and C have a kesterite phase with secondary phases, such as Cu_2−xS, SnS₂ and SnS. The annealed CZTS thin film using stacking order A showed a very dense morphology without voids. On the other hand, the annealed CZTS thin films using stacking orders B and C contained the volcano shape voids (B) and Sn-based secondary phases (C) on the surface of the annealed thin films. The direct band gap energies of the CZTS thin films were approximately 1.45 eV (A), 1.35 eV (B) and 1.1 eV (C).     

Spherical NiCu phyllosilicate photocatalysts for hydrogen generation

To enhance the photocatalytic performance of semiconductors, a highly active and durable SiO₂@xNiCuPS photocatalyst was evaluated for photocatalytic hydrogen generation. The photocatalyst was prepared by a hydrothermal method using SiO₂ spheres, and a 1:1 Cu:Ni mixture (5 and 10 wt%). The reaction gave a highly stable phyllosilicate material with a core@shell structure. The materials were characterized by a range of techniques. DRS data revealed indirect optical transitions at 1.5 eV and 2.75 eV for the SiO₂@5NiCuPS and SiO₂@10NiCuPS materials. The new photocatalysts were successfully tested for hydrogen generation under visible irradiation to give H₂ yields of 184 and 47 μmol g⁻¹. min⁻¹ for SiO₂@5NiCuPS and SiO₂@10NiCuPS, respectively. The data suggest that the enhanced activity of adding Cu to Ni to form Ni/Cu phyllosilicates is not due to NiCu alloy formation but due to changes in the support morpholohgy brought about by metal-support interactions. The catalysts were stable over 4 repeat reaction cycles.     

Cu–MoS2/rGO hybrid material for enhanced hydrogen evolution reaction performance

Cu doped MoS₂ (Cu–MoS₂)/reduced graphene oxide (rGO) (Cu–MoS₂/rGO) hybrid material is fabricated by a facile one-step solvothermal method. The X-ray diffraction (XRD) results suggest that the doping of Cu does not alter the crystal structure of MoS₂. X-ray photoelectron spectroscopy (XPS) analysis reveal that the doping of Cu atoms influences the electronic structure of MoS₂, which is favorable to increase active sites of edges. Electrochemical impedance spectroscopy (EIS) results indicate that Cu–MoS₂/rGO performed a faster charge-transfer in comparison to MoS₂/rGO hybrid. In addition, the resultant Cu–MoS₂/rGO catalyst with Cu/Mo mole ratio of 9% exhibits a lower overpotential of 199 mV at 10 mA cm⁻², small Tafel slop of 44 mV dec⁻¹ and cycling stability, indicative of enhanced electrocatalytic activity towards HER. The improved performance is attributed to the increased active sites and a synergistic effect between copper and molybdenum, leading to electronic structure change and charge redistribution of MoS₂.     

Facile hydrothermal synthesis of 3D flower‐like La‐MoS2 nanostructure for photocatalytic hydrogen energy production

Three‐dimensional (3D) flower‐like MoS₂ nanostructures were prepared via facile and cost‐effective hydrothermal method by varying hydrothermal temperature (180°C, 200°C, and 220°C) and reaction time (6, 12, 24, and 36 hours). The results demonstrated that the sample prepared at 200°C for 24 hours have 3D flower‐like MoS₂ nanostructure (SEM) with hexagonal phase structure (XRD). Moreover, this novel photocatalyst was also modified by lanthanum element (La³⁺) with varying La³⁺ atomic ratio (0.5%, 1%, 2%, 3%, and 4%). Interestingly, the La³⁺ incorporation into MoS₂ has good effect on the specific surface area and optical properties of MoS₂ photocatalyst. Furthermore, the flower‐like 3%LaMoS₂ nanostructure photocatalyst exhibited 5.2‐times higher efficiency for H₂ evolution via water splitting as compared with pure MoS₂ under the same conditions. This superior efficiency of the photocatalyst for H₂ production arises from the positive synergistic effect between MoS₂ and lanthanum in the composite photocatalyst due to higher surface area, enhanced light absorption, and inhibited electron‐holes pair recombination. This study presents an expensive photocatalyst for energy production via water spitting.     

Supported mesoporous Cu/CeO2-δ catalyst for CO2 reverse water–gas shift reaction to syngas

The design and development of a high performance hydrogenation catalyst is an important challenge in the utilization of CO₂ as resources. The catalytic performances of the supported catalyst can be effectively improved through the interaction between the active components and the support materials. The obtained results demonstrated that the oxygen vacancies and active Cu⁰ species as active sites can be formed in the Cu/CeO_2-δ catalysts by the H₂ reduction at 400 °C. The synergistic effect of the surface oxygen vacancies and active Cu⁰ species, and Cu⁰–CeO_2-δ interface structure enhanced catalytic activity of the supported xCu/CeO_2-δ catalysts. The electronic effect between Cu and Ce species boosted the adsorption and activation performances of the reactant CO₂ and H₂ molecules on the corresponding Cu/CeO_2-δ catalyst. The Cu/CeO_2-δ catalyst with the Cu loading of 8.0 wt% exhibited the highest CO₂ conversion rate in the RWGS reaction, reaching 1.38 mmol·g_cat⁻¹ min⁻¹ at 400 °C. Its excellent catalytic performance in the RWGS reaction was related to the complete synergistic interaction between the active species via Ce³⁺-□-Cu⁰ (□: oxygen vacancy). The Cu/CeO_2-δ composite material is a superior catalyst for the RWGS reaction because of its high CO₂ conversion and 100% CO selectivity.     

Effect of alkaline-doping on photoelectrochemical activity of electrodeposited cuprous oxide films

P-type Cu₂O films with alkaline ions (Li⁺, Na⁺ and K⁺) of unintentional dopants on indium tin oxide coated glass substrate are successfully fabricated via a simple electrodeposition method for photoelectrochemical (PEC) hydrogen generation. The SEM and XRD analysis show the as-grown films with the pyramid-like morphology and cubic structure, and the composition of alkaline-doped Cu₂O films are examined using XPS spectroscopy to demonstrate the substitution of alkaline ions in the Cu₂O lattice. The optical analyses, including the absorbance and low-temperature photoluminescence spectra, confirm a bandgap of 2.3 eV and the presence of structural defects in alkaline-doped Cu₂O films. The Mott-Schottky plot shows the flat band potentials of the alkaline-doped Cu₂O films to be approximately ?0.1 V and the hole concentrations in the order of 10¹⁷ cm^?3. Significantly, the Cu₂O:Li film photocathode exhibits a higher photocurrent of ?2.2 mA cm^?2 at a potential of ?0.6 V vs Ag/AgCl which are greater than those of Cu₂O:K and Cu₂O:Na films due to greater preferred orientation degrees along (111) and less structural defects, because the ionic radii of Cu and Li is similar. These results demonstrate the great potential of alkaline doped Cu₂O films in solar-related applications.     

CuO-TiO2 nanostructures prepared by chemical and electrochemical methods as photo electrode for hydrogen production

In present study, copper (II) oxide (CuO) nanostructures were separately synthesized via chemical and electrochemical methods. CuO were coated with chemically synthesized titanium dioxide (TiO₂). Morphological and structural properties of CuO and TiO₂ coated CuO (CuO-TiO₂) materials were examined via field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). FESEM images showed that nanowire like CuO formed at both chemical and electrochemical techniques. TiO₂ nanoparticles were homogenously distributed all over CuO surfaces. XRD pattern revealed CuO has monoclinic crystal structure with metallic Cu. Moreover, rutile TiO₂ crystallized in the tetragonal crystal structure. Electrochemical impedance spectroscopy (EIS) and potentiodynamic (PD) polarization measurements were utilized to study electro catalytic performance of the materials towards hydrogen evolution reaction (HER). The values of both energy consumption, and energy efficiency were determined as 329.43 kJ mol^?1 and 86.0% at ?50 mA cm^?2 current density for HER on electrochemically synthesized CuO-TiO₂ at 25 °C.