Water Splitting Cells Research Articles

Parallel multi-stacked photoanodes of Sb-doped p–n homojunction hematite with near-theoretical solar conversion efficiency

Developing transparent and efficient photoanodes is a challenging but essential task in tandem photoelectrochemical cell for unassisted solar water splitting without an external bias. Here we report construction of p–n homojunction hematite photoanodes by hybrid microwave annealing-induced single antimony doping, which results in the gradually-increased valence states from the surface to the inside by the unique features of hybrid microwave annealing. The Sb-doped p–n homojunction hematite photoanode exhibits improved performance and displays a good transparency, achieving a stable photocurrent density of ~4.21 mA cm−2 at 1.23 VRHE under 100 mW cm−2 solar irradiation, which is comparable to the reported state-of-the-art hematite photoanodes. More importantly, a parallel-connected stack of six photoanodes of transparent p–n homojunction records a near-theoretical photocurrent density of ~10 mA cm–2 at 1.23 VRHE under standard photoelectrochemical water splitting conditions, which serves as a useful reference for hematite photoanodes and promises its practical application for unbiased photoelectrochemical water splitting.

“There is plenty of energy at the bottom”: A spectral conversion approach for upconversion-powered water-splitting PEC cell

An avant-garde step towards the use of the long infrared tail of the incident solar radiation with untapped and crucial applications in photocatalysis and energy harvesting schemes is presented: “there is plenty of energy at the bottom”. In detail, a pure photonic approach to enhance titanium dioxide (TiO2) photocatalytic activity is proposed, by using rare-earth doped luminescent glassy materials, capable of performing NIR-to-UV-VIS spectral conversion (up-conversion). Therefore we report infrared-driven boosting of green hydrogen production in a photo-electrochemical water-splitting cell using TiO2 electrodes, revisiting the original design of Fujishima and Honda fifty years later. This proof-of-concept comprises infrared-induced hydrogen and oxygen evolution via water-splitting and determines univocally the role of a solely photonic effect to split water. Thus, the conversion of the incident NIR radiation, before its interaction with the photocatalyst, emerges as a significant contribution to the state-of-the-art for an effective harvest of the near-infrared portions of sunlight.

Partial oxidation of Rh/Ru nanoparticles within carbon nanofibers for high-efficiency hydrazine oxidation-assisted hydrogen generation

Hydrazine oxidation reaction (HzOR), an alternative to oxygen evolution reaction, effectively mitigates hydrazine pollution while achieving energy-efficient hydrogen production. Herein, partially oxidized Ru/Rh nanoparticles embedded in carbon nanofibers (CNFs) are fabricated as a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and HzOR. The presence of multiple components including metallic Ru and Rh and their oxides provides numerous electrochemically active sites and superior charge transfer properties, thus improving the electrocatalytic performance. Additionally, the confinement of the active components within CNFs further enhances structural stability. Consequently, the optimized electrocatalyst exhibits ultralow overpotentials of 16 mV at 10 mA cm−2 and 176 mV to reach an industry-level current density of 1 A cm−2 for HER, considerably outperforming the benchmark Pt/C catalyst. Furthermore, it shows an outstanding anodic HzOR activity, achieving a small potential of –0.019 V to generate 10 mAcm−2. A two-electrode overall hydrazine splitting (OHzS) cell prepared using the electrocatalyst operates at a compelling voltage that is 1.953 V lower than that of the overall water splitting (OWS) cell at 200 mA cm−2. Furthermore, the OHzS cell achieves a hydrogen production rate of 1.17 mmol h−1, which is 15-fold that of OWS. Additionally, Rh1Ru1Ox-CNFs-350 is used to construct a Zn-hydrazine battery with excellent performance. This study presents an effective system for achieving high-yielding green H2 production with low energy consumption while simultaneously addressing hydrazine pollution.

Synthesis, characterization and application of quinoxaline-based organic dyes as anodic sensitizers in photoelectrochemical cells

Three new D-A-π-A organic dyes (1a-c) containing a 2,3-diphenylquinoxaline core as the main chromophore were designed to act as sensitizers for the TiO2-based photoanode of dye-sensitized photoelectrochemical cells (DS-PEC) for water splitting. The dyes structures featured a cyanoacrylic acid group as the terminal acceptor/anchoring moiety and three different donor groups of moderate strength, namely mono- and dialkoxy-substituted benzenes, which were introduced to modulate the energies of the respective HOMO levels and enable the electron transfer from a Ru-based molecular water oxidation catalyst (WOC). Dyes 1a-c were synthesized following a C–H activation strategy and fully characterized. In addition, the previously known catalyst Ru(bda)(PyP)2 (bda = 2,2′-bipyridine-6,6′-dicarboxylate; PyP = pyridin-4-methyl phosphonic acid) was also prepared by modification of a reported procedure. The dynamics of charge transfer processes involving the dyes adsorbed on nanocrystalline TiO2 films were investigated by means of transient absorption spectroscopy. Photo-electrochemical experiments carried out on photoanodes functionalized with 1a-c and Ru(bda)(PyP)2 in 0.1 M aq. Na2SO4 electrolyte showed the production of photocurrents up to ca. 0.15 mA cm−2 at + 0.5 V vs. NHE, and highlighted how modifications of the TiO2 staining procedure can lead to significant differences in cell performances.

Unbiased Photoelectrochemical H2O2 Coupled to H2 Production via Dual Sb2S3‐Based Photoelectrodes with Ultralow Onset Potential

AbstractThe productions of hydrogen peroxide (H2O2) and hydrogen (H2) in a photoelectrochemical (PEC) water splitting cell suffer from an onset potential that limits solar conversion efficiencies. Moreover, the formation of H2O2 through two‐electron PEC water oxidation reaction competes with four‐electron oxidation evolution reaction. Herein, we developed the surface selenium doped antimony trisulfide photoelectrode with the integrated ruthenium cocatalyst (Ru/Sb2(S,Se)3) to achieve the low onset potential and high Faraday efficiency (FE) for selective H2O2 production. The photoanode exhibits an outstanding average FE of 85 % in the potential range of 0.4–1.6 VRHE and the H2O2 yield of 1.01 μmol cm−2 min−1 at 1.6 VRHE, especially at low potentials of 0.1–0.55 VRHE with 80.4 % FE. Impressively, an unassisted PEC system that employs light and electrolyte was constructed to simultaneously produce H2O2 and H2 production on both the Ru/Sb2(S,Se)3 photoanode and the Pt/TiO2/Sb2S3 photocathode. The integrated system enables the average PEC H2O2 production rate of 0.637 μmol cm−2 min−1 without applying any addition bias. To our knowledge, this is the first demonstration that Sb2S3‐based photoelectrodes exhibit H2O2/H2 two‐side production with a strict key factor of the system, which represents its powerful platform to achieve high efficiency and productivity and the feasibility to facilitate value‐added products in neutral conditions.

Unbiased Photoelectrochemical H2O2 Coupled to H2 Production via Dual Sb2S3-Based Photoelectrodes with Ultralow Onset Potential.

The productions of hydrogen peroxide (H2O2) and hydrogen (H2) in a photoelectrochemical (PEC) water splitting cell suffer from an onset potential that limits solar conversion efficiencies. Moreover, the formation of H2O2 through two-electron PEC water oxidation reaction competes with four-electron oxidation evolution reaction. Herein, we developed the surface selenium doped antimony trisulfide photoelectrode with the integrated ruthenium cocatalyst (Ru/Sb2(S,Se)3) to achieve the low onset potential and high Faraday efficiency (FE) for selective H2O2 production. The photoanode exhibits an outstanding average FE of 85 % in the potential range of 0.4-1.6 VRHE and the H2O2 yield of 1.01 μmol cm-2 min-1 at 1.6 VRHE, especially at low potentials of 0.1-0.55 VRHE with 80.4 % FE. Impressively, an unassisted PEC system that employs light and electrolyte was constructed to simultaneously produce H2O2 and H2 production on both the Ru/Sb2(S,Se)3 photoanode and the Pt/TiO2/Sb2S3 photocathode. The integrated system enables the average PEC H2O2 production rate of 0.637 μmol cm-2 min-1 without applying any addition bias. To our knowledge, this is the first demonstration that Sb2S3-based photoelectrodes exhibit H2O2/H2 two-side production with a strict key factor of the system, which represents its powerful platform to achieve high efficiency and productivity and the feasibility to facilitate value-added products in neutral conditions.

Tuning the optoelectronic properties of graphene monoxide by electric field, strain and heterostructure with Cd[formula omitted] ([formula omitted]=S, Se or Te)

Hydrogen production via photocatalytic water splitting has become a promising technique for developing clean and sustainable energy system. Low-dimensional carbon-based materials are under focus to develop high efficiency visible-light photocatalysts. Among the various 2D graphene-based materials, graphene oxides (GO) attracted attention in recent years. Recently identified GO such as graphene monoxide (GMO) shows promising electronic structure characteristics such as direct band gap behavior, high optical absorption, and well-dispersed band edges to use them in higher efficiency optoelectronic applications. Nevertheless, its valence band edge is distant from the water oxidation potential, and band gap value exceeds the ideal band gap required to effectively harvest solar energy, which minimizes its practical application in photocatalytic water splitting. Here, using hybrid density functional theory calculations, we are exploring the effect of applied electric field/strain on the photocatalytic water splitting and photovoltaic properties of GMO. We found that even after applying an electric field or strain, GMO retains the desirable direct band gap behavior, well-dispersed bands at the band edges, and high optical absorption in the visible range. Further, the band alignment analysis suggests that the application of compressive strain enhances the efficiency of photocatalytic water splitting by straddling the band edges with water redox potentials. Additionally, we explored the optoelectronic properties of GMO by designing its heterostructure with CdS, CdSe, and CdTe monolayers. Remarkably, the studied heterostructures demonstrated superior optical absorption in the visible spectrum and a low recombination rate of charge carriers by separating them across different layers with type-II band alignment; suggesting that these heterostructures will be efficient candidates for visible energy photocatalytic water splitting and higher-efficiency solar cells.

Surface‐Segregated IrCo Nanoparticles on CoO Nanosheets with Ultralow Ir Loading for Efficient Acidic Water Splitting

AbstractIrO2 is the benchmark catalyst for acidic oxygen evolution reaction (OER), however, the high cost and low earth abundance hinder its large‐scale application. Herein, surface‐segregated IrCo nanoparticles on CoO nanosheets with a strong electronic interaction are synthesized through the ion exchange‐pyrolysis method. The resulting IrCo−CoO heterostructures, containing an ultra‐low Ir content of 4.73 wt %, demonstrate exceptional performance in the acidic OER. The catalyst exhibits a low overpotential of 270 mV at a current density of 10 mA cm−2 and remarkable stability, with noticeable activity decay observed only after 140 hours of continuous operation. These results surpass most reported Ir‐based electrocatalysts. Specifically, the mass activity at the overpotential of 300 mV for the IrCo−CoO catalyst reaches 124.52 mA mgIr−1, which is 20 times higher than that of commercial IrO2. Furthermore, we constructed a home‐made overall water splitting cell utilizing IrCo−CoO heterostructures as both anode and cathode electrodes, achieving a current density of 10 mA cm‐−2 at a voltage of 1.51 V. Our findings present a promising strategy for designing high‐efficient catalysts with significantly reduced noble metals loading.

P-NiFe2O4/N-Doped Carbon Nanotubes/NiFe Multi-Phase Heterojunctions for Overall Water Splitting and Urea Electrolysis.

The design and construction of highly efficient electrocatalysts for overall water splitting and urea electrolysis are significantly important for promoting energy conversion and realizing green hydrogen production. In this work, we constructed a multi-phase heterojunction through a simple hydrothermal and phosphorization process. The P-doped NiFe2O4 (P-NiFe2O4) nanoparticles were uniformly anchored on the bamboo-like N-doped carbon nanotubes (NCNTs) grown via a NiFe-alloy autocatalysis. The electronic structure and coordination environment of active species were optimized by the synergistic action of P doping, well-dispersed ultrafine NiFe2O4, and NCNTs matrix with good conductivity, enhancing their quantity and activity for electrocatalysis. Consequently, the P-NiFe2O4/NCNTs/NiFe exhibits excellent HER and OER activities with an overpotential of 111 and 266 mV at 10 mA cm-2 in 1 M KOH, respectively. The symmetrical overall water-splitting cell using P-NiFe2O4/NCNTs/NiFe as both anode and cathode delivers 10 mA cm-2 at a voltage of 1.604 V in 1 M KOH. Notably, the two-electrode cell requires a low voltage of 1.467 V to achieve a current density of 10 mA cm-2 in 1 M KOH solution with 0.6 M urea. This designed catalysts display outstanding reaction kinetics and catalytic stability. This work provides useful guidance for applying transition metal-based catalysts for hydrogen production.

Environment-Benign Colloidal Quantum Dots-Modified Dual Photoelectrodes for Self-Biased Photoelectrochemical Water Splitting.

Photoelectrochemical (PEC) water splitting based on colloidal quantum dots (QDs) presents a promising approach for utilizing solar energy to produce green hydrogen energy. Previous research has been mainly focused on the single-photoelectrode QDs-PEC device operated under external bias, while the investigation of dual-photoelectrode configuration for self-biased QDs-PEC system is still lacking. In this work, two types of eco-friendly Cu-AISe/ZnSe:Cu (CZAC) and Mn-AIS/ZnS@Cu (MAZC) QDs were used to respectively sensitize the semiconductor n-type TiO2 and p-type Cu2O photoelectrodes, which acted as the photoanode and photocathode to build a heavy metal-free QDs-based bias-free solar water splitting cell, yielding a maximum photocurrent density of 0.47 mA cm-2 and a solar-to-hydrogen (STH) efficiency of 0.4 % under 1 sun AM 1.5G illumination (100 mW cm-2). Moreover, approximate 692 nmol of H2 and 355 nmol of O2 with molar ratio of ~2 : 1 was detected after two hours of continuous light illumination, demonstrating the effective overall water splitting. This work indicates a significant advancement towards the realization of a cost-effective, efficient and "green" QDs-based artificial solar-to-fuel conversion system.

Plasmon-enhanced sub-Debye-length nanogap photoelectrochemical cells for field-assisted electrolyte-free water splitting

This work studies pure water splitting (i.e., no additional electrolyte) using plasmonic sub-Debye-length nanogap photoelectrochemical cells (NPECs). With 60 nm Au gratings covered by 4 nm amorphous TiO2 under 638 nm normal incident illumination, we demonstrate up to 66 × higher photocurrent at 1.5 V than that of Au-gratings-only NPECs. In addition, we are able to efficiently drive pure water splitting at voltages as low as 1.3 V, which is very close to the theoretical thermodynamic potential threshold of 1.23 V. Our electromagnetic finite difference time domain (FDTD) simulation results (Lumerical Inc.) show a 240 × increase in the electric field intensity near the TiO2 layer compared to the incident electric field. We attribute our observations to 1) Hot spots generated by surface plasmonic resonance (SPR) on Au gratings, which greatly increase the number of electron-hole pairs; 2) The 60 nm gap distance between electrodes, which is smaller than the Debye length of pure water (∼220 nm) resulting in a much higher electric field by eliminating the shield effect and by coupling two half-reactions of water splitting together; and 3) The 4 nm amorphous TiO2, which improves hot carriers separation. Our NPEC is a promising device for efficient hydrogen production enabling the utilization of visible light.

In Situ and Continuous Decoding Hydrogen Generation in Solar Water-Splitting Cells.

Photoelectrochemical (PEC) water splitting is gaining recognition as an effective method for producing green hydrogen. However, the absence of in situ, continuous decoding hydrogen generation tools hampers a detailed understanding of the physics and chemistry involved in hydrogen generation within PEC systems. In this article, we present a quantitative, spatiotemporally resolved optical sensor employing a fiber Bragg grating (FBG) to probe hydrogen formation and temperature characteristics in the PEC system. Demonstrating this principle, we observed hydrogen formation and temperature changes in a novel cappuccino cell using a BiVO4/TiO2 photoanode and a Cu2O/CuO/TiO2 photocathode. Our findings demonstrate that FBG sensors can probe dynamic hydrogen formation at 0.5 s temporal resolution; these sensors are capable of detecting hydrogen concentrations as low as 0.6 mM. We conducted in situ and continuous monitoring of hydrogen and temperature to ascertain various parameters: the rate of hydrogen production at the photocathode surface, the time to reach hydrogen saturation, the distribution of hydrogen and temperature, and the rate of hydrogen transfer in the electrolyte under both external bias and unbiased voltage conditions. These results contribute valuable insights into the design and optimization of PEC water-splitting devices, advancing the in situ comprehensive monitoring of PEC water-splitting processes.

Electronic transfer and structural reconstruction in porous NF/FeNiP-CoP@NC heterostructure for robust overall water splitting in alkaline electrolytes

Multimetal phosphides derived from metal-organic frameworks (MOFs) have garnered significant interest owing to their distinct electronic configurations and abundant active sites. However, developing robust and efficient catalysts based on metal phosphides for overall water splitting (OWS) remains challenging. Herein, we present an approach for synthesizing a self-supporting hollow porous cubic FeNiP-CoP@NC catalyst on a nickel foam (NF) substrate. Through ion exchange, the reconstruction chemistry transforms the FeNi-MOF nanospheres into intricate hollow porous FeNi-MOF-Co nanocubes. After phosphorization, numerous N, P co-doped carbon-coated FeNiP-CoP nanoparticles were tightly embedded within a two-dimensional (2D) carbon matrix. The NF/FeNiP-CoP@NC heterostructure retained a porous configuration, numerous heterogeneous interfaces, distinct defects, and a rich composition of active sites. Moreover, incorporating Co and the resulting structural evolution facilitated the electron transfer in FeNiP-CoP@NC, enhancing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) processes. Consequently, the NF/FeNiP-CoP@NC catalyst demonstrated very low overpotentials of 78 mV for OER and 254 mV for HER in an alkaline medium. It also exhibited excellent long-term stability at various potentials (@10 mA cm−2, @20 mA cm−2, and @50 mA cm−2). As an overall water splitting cell, it required only 1.478 V to drive a current density of 50 mA cm−2 and demonstrated long-term stability. Density functional theory (DFT) calculations revealed a synergistic effect between multimetal phosphides, enhancing the intrinsic OER and HER activities of FeNiP-CoP@NC. This work not only elucidates the role of heteroatom induction in structural reconstruction but also highlights the importance of electronic structure modulation.

Maximized nanojunctions in Pd/SnO2 nanoparticles for ultrasensitive and rapid H2 detection

H2 energy has gained massive attraction as a promising candidate for future energy sources. However, the explosive properties of H2 arouse significant safety concerns, emphasizing the need for the development of real-time H2 detection systems. This study presents the fabrication of an ultrasensitive and selective H2 gas sensor using Pd/SnO2 nanoparticles (NPs) synthesized through the utilization of Pluronic F-127. Pluronic F-127 improves the dispersion and regulates the particle size of Pd NPs. Pd/SnO2 NPs, which are comprised of numerous nanojunctions, exhibit H2 response of 27,190 and a response time of 3 s when exposed to 50 ppm of H2 at 100 °C. The practical applicability of Pd/SnO2 NPs was demonstrated by detecting H2 generated from water-splitting cells, exhibiting promising features for H2 energy industries. Overall, the synthetic method of this study proposes advanced strategies for development of sensing materials with maximized gas sensing performance.

In-situ impedance spectroscopy on copper oxide scales under potential controlled oxidation at high temperatures

In recent years, copper oxide (Cu2O) has gained significant attention for its multifaceted role as a catalyst, photocatalyst and semiconductor. Possessing a p-type conductivity and a bandgap of 2.17 eV, Cu2O emerges as an ideal candidate for applications such as water splitting and photovoltaic cells. However, to utilize its full potential, an in-depth understanding of the electrical properties of Cu2O in terms of defect density and defect mobility is required. This knowledge forms the basis for the targeted production of oxides with precisely tuned electrical properties.Extensive research on thermal oxidation under varied conditions has been performed to clarify the mechanisms governing oxide formation and growth. However, the in-situ investigation of the electrical properties of the oxide layers during their formation process is challenging.This work introduces a new method for the controlled oxidation of copper, while concurrently offering an in-depth investigation of the electrical properties of these nanometer-thick oxide layers. The implemented arrangement of potentiostat and frequency response analyzer enables their artifact-free combination. Performing HT-CV measurements in a solid electrolyte cell-setup allows to control the (potential-dependent) oxygen pressure at the copper surface. Using HT-CV, the current represents the kinetics of the redox reactions and the electric charge corresponds to the amount of substance converted. In-situ electrochemical impedance data are used to determine the electrical properties of the controlled grown layers. As a result, the defect density is obtained as a function of the oxygen partial pressure.

Enhancing electrochemical water-splitting efficiency with superaerophobic nickel-coated catalysts on Chinese rice paper

The quest for efficient hydrogen production highlights the need for cost-effective and high-performance catalysts to enhance the electrochemical water-splitting process. A significant challenge in developing self-supporting catalysts lies in the high cost and complex modification of traditional substrates. In this study, we developed catalysts featuring superaerophobic microstructures engineered on microspherical nickel-coated Chinese rice paper (Ni-RP), chosen for its affordability and exceptional ductility. These catalysts, due to their microspherical morphology and textured surface, exhibited significant superaerophobic properties, substantially reducing bubble adhesion. The nickel oxy-hydroxide (NiOxHy) and phosphorus-doped nickel (PNi) catalysts on Ni-RP demonstrated effective roles in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), achieving overpotentials of 250 mV at 20 mA cm−2 and 87 mV at −10 mA cm−2 in 1 M KOH, respectively. Moreover, a custom water-splitting cell using PNi/Ni-RP and NiOxHy/Ni-RP electrodes reached an impressive average voltage of 1.55 V at 10 mA cm−2, with stable performance over 100 h in 1 M KOH. Our findings present a cost-effective, sustainable, and easily modifiable substrate that utilizes superaerophobic structures to create efficient and durable catalysts for water splitting. This work serves as a compelling example of designing high-performance self-supporting catalysts for electrocatalytic applications.

Laser-Printed Photoanode: Femtosecond Laser-Induced Crystalline Phase Transformation of WO3 Nanorods for Space-Efficient and Flexible Thin-Film Solar Water-Splitting Cells.

Despite its potential for clean hydrogen harvesting, photoelectrochemical (PEC) water-splitting cells face challenges in commercialization, particularly related its harvesting performance and productivity at an industrial scale. Herein, a facile fabrication method of flexible thin-film photoanode for PEC water-splitting to overcome these limitations, based on laser processing technologies, is proposed. Laser-induced graphene, a carbon structure produced through direct laser writing carbonization (DLWC), plays a dual role: a flexible and stable current collector and a substrate for the hydrothermal synthesis of tungsten trioxide (WO3) nanorods (NRs). To facilitate water-splitting, a femtosecond-pulsed laser (fs laser) is focused on the WO3 NRs, converting their crystalline phase from pristine orthorhombic to monoclinic structure without thermal damage. With NiFe layered double hydroxide (LDH) catalyst, the flexible thin-film photoanode exhibits good PEC performance (1.46mAcm-2 at 1.23 VRHE) and retains ≈90% of its performance after 3000 bending cycles. With its excellent mechanical properties, the flexible photoanode can be operated in various shapes with different curvatures, enabling space-efficient PEC water-splitting by loading larger photoanode within a given space. This study is expected to contribute to the advancement of large-scale solar water-splitting cells, introducing a new approach to enhance H2/O2 production and expand its application range.

Prussian blue analogue-derived Co-Ni5P4 porous nanosheet arrays composite coal-based carbon nanofibers as efficient self-supported electrocatalyst for overall water splitting

The development of economical, earth-rich, and high-performance transition metal phosphides electrocatalysts is crucial for water splitting. Herein, the NiCo PBA/Ni(OH)2 hierarchical nanostructure arrays are in situ grown on the coal-based carbon nanofibers (C-CNFs) using hydrothermal and co-precipitation methods. Subsequently, the Co-doped Ni5P4 porous nanosheet arrays composite coal-based carbon nanofibers electrocatalyst (Co-Ni5P4@C-CNFs) is obtained through low-temperature phosphorization process. Benefiting from cation-doped, porous nanosheet arrays structure and self-supported conductive substrates, the Co-Ni5P4@C-CNFs has excellent electrocatalytic performance for overall water splitting. It provides low overpotentials of 75 mV for hydrogen evolution reaction (HER) and 231 mV for oxygen evolution reaction (OER) to achieve the current density of 10 mA cm−2 in 1 M KOH electrolyte. Furthermore, the Co-Ni5P4@C-CNFs demonstrates a low overall water splitting cell voltage of 1.537 V at current density of 10 mA cm−2 and remarkable long-term stability for over 160 h. It outperforms the most transition metal phosphide bifunctional electrocatalysts reported to date. This research provides a novel strategy for synthesizing high-performance transition metal phosphides bifunctional electrocatalysts.

Non-innocent partners: bias distribution between photoanodes and cathodes in photoelectrochemical overall water-splitting cells.

Non-innocent partners: bias distribution between photoanodes and cathodes in photoelectrochemical overall water-splitting cells.

Al-Ce co-doped BaTiO3 nanofibers as a high-performance bifunctional electrochemical supercapacitor and water-splitting electrocatalyst

Supercapacitors and water splitting cells have recently played a key role in offering green energy through converting renewable sources into electricity. Perovskite-type electrocatalysts such as BaTiO3, have been well-known for their ability to efficiently split water and serve as supercapacitors due to their high electrocatalytic activity. In this study, BaTiO3, Al-doped BaTiO3, Ce-doped BaTiO3, and Al-Ce co-doped BaTiO3 nanofibers were fabricated via a two-step hydrothermal method, which were then characterized and compared for their electrocatalytic performance. Based on the obtained results, Al-Ce co-doped BaTiO3 electrode exhibited a high capacitance of 224.18 Fg−1 at a scan rate of 10 mVs−1, high durability during over the 1000 CV cycles and 2000 charge–discharge cycles, proving effective energy storage properties. Additionally, the onset potentials for OER and HER processes were 11 and − 174 mV vs. RHE, respectively, demonstrating the high activity of the Al-Ce co-doped BaTiO3 electrode. Moreover, in overall water splitting, the amount of the overpotential was 0.820 mV at 10 mAcm−2, which confirmed the excellent efficiency of the electrode. Hence, the remarkable electrocatalytic performance of the Al-Ce co-doped BaTiO3 electrode make it a promising candidate for renewable energy technologies owing to its high conductivity and fast charge transfer.