As-prepared Photoelectrode Research Articles

A novel Pt modified AlGaN/Si double-junction nanostructure for stable and self-powered solar blind photoelectrochemical photodetection

Simultaneously searching for self-powered, efficient, stable photoelectrode is the key to realizing the next-generation energy-efficient and sustainable integrated solar blind photoelectrochemical (PEC) photodetector. In this work, a Pt modified AlGaN/Si double-junction nanostructure with an n++ AlGaN/p++ AlGaN tunnel junction (TJ) and a AlGaN/Si junction is reported to achieve stable and self-powered solar blind photodetection. PEC tests demonstrate that the photocurrent density of the Pt modified AlGaN with n++ AlGaN/p++ AlGaN TJ photoelectrode can reach up to −56.1 μA/cm2 under 255 nm light irradiation with 1.1 mW/cm2 at 0 V bias versus a Pt counter electrode in a three-electrode configuration. Time-steady photoluminescence and XRD spectra are carried out and confirm the inherent optical and physical properties of this nanostructure. In addition, the multicycle and long-term stability measurement shows an excellent switching behavior even after being placed in the air for one month with a photocurrent density of −44.9 μA/cm2 (80% of its initial photocurrent). Furthermore, the PEC performance of the Pt modified AlGaN with n++ AlGaN/p++ AlGaN tunnel junction photoelectrode is evaluated in different light wavelengths, light intensities, bias potential and H2SO4 concentrations. These results demonstrate that the as-prepared photoelectrode has a great potential application in stable self-powered solar blind photodetector.

Building of a three-dimensional apta-nano interface using silver nanoflower for photoelectrochemical detection of carcinoembryonic antigen

Enhancing the sensitivity of photoelectrochemical (PEC) assays poses a challenging task. This study proposes a method to improve the sensitivity of PEC assays by creating a three-dimensional (3D) apta-nano interface using silver nanoflowers (AgNFs) with a 3D flower-like structure as a substrate. The aptamer (Apt) was immobilized on the surface of the AgNF-loaded gold nanoparticles (AuNPs) through the dual action of polyA blocking and Au-S bonding. Despite using cadmium sulfide quantum dots (CdS QDs) as the sole photoactive material, the as-prepared photoelectrode still showed excellent sensitivity. Using carcinoembryonic antigen (CEA) as a model target, the variation value of photocurrent (ΔI) exhibited good linear correlation (R2 = 0.9974) with the logarithm of CEA concentration in a wide detection range from 0.001 to 100 ng mL−1, and the detection limit was as low as 0.64 pg mL−1. In the assay of CEA in 1% serum, the recoveries reached 98.70 ∼ 99.63% with a low relative standard derivation (RSD) ranging from 1.11% to 2.05%. This study introduces novel concepts for the development of PEC sensors, potentially enhancing their utility in the clinical detection of disease markers.

A semiconductor-electrocatalyst nano interface constructed for successive photoelectrochemical water oxidation

Photoelectrochemical water splitting has long been considered an ideal approach to producing green hydrogen by utilizing solar energy. However, the limited photocurrents and large overpotentials of the anodes seriously impede large-scale application of this technology. Here, we use an interfacial engineering strategy to construct a nanostructural photoelectrochemical catalyst by incorporating a semiconductor CdS/CdSe-MoS2 and NiFe layered double hydroxide for the oxygen evolution reaction. Impressively, the as-prepared photoelectrode requires an low potential of 1.001 V vs. reversible hydrogen electrode for a photocurrent density of 10 mA cm−2, and this is 228 mV lower than the theoretical water splitting potential (1.229 vs. reversible hydrogen electrode). Additionally, the generated current density (15 mA cm−2) of the photoelectrode at a given overpotential of 0.2 V remains at 95% after long-term testing (100 h). Operando X-ray absorption spectroscopy revealed that the formation of highly oxidized Ni species under illumination provides large photocurrent gains. This finding opens an avenue for designing high-efficiency photoelectrochemical catalysts for successive water splitting.

Direct growth of Bi2S3 nanorods onto the Bi2MoO6 nanoflakes: A promising heterostructure for efficient photoelectrochemical water-splitting application

Fabrication of heterostructure promises a potential approach to increase the hydrogen production performance of photoelectrodes under solar light irradiation. Herein, a two-step hydrothermal method was introduced to grow directly Bi2S3 nanorods onto the Bi2MoO6 nanoflakes to form Bi2MoO6/Bi2S3 heterostructure. This work is aimed to synthesize heterostructure photoelectrode for photoelectrochemical water splitting application. The as-prepared photoelectrodes were analyzed by using X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectra, and UV–vis spectroscopy. As a result, the heterostructure Bi2MoO6/Bi2S3 indicated a dramatic improvement in the PEC properties (1.41 mA/cm2). From the X-ray photoelectron spectroscopy valence band measurement, the suitable bandgap between Bi2MoO6 and Bi2S3 can promote charge transfer across the junction interface and suppress electron-hole recombination. Furthermore, coupling a narrow bandgap material Bi2S3 with Bi2MoO6 can form a type II- heterostructure, leading to enhancement of the light absorption under visible light irradiation. This work provides a promising and efficient photoanode for light harvesting and hydrogen production.

Photoelectrocatalytic degradation of m-chloronitrobenzene through rGO/g-C3N4/TiO2 nanotube arrays photoelectrode under visible light: Performance, DFT calculation and mechanism

The photoelectrocatalytic (PEC) technology by combing photocatalysis and electrochemistry has attracted widespread concerns in the organic pollutant degradation due to its effective degradation performance. TiO2 nanotube arrays (TNAs) can be used not only as photocatalyst but also as electrode and is regarded as a popular photoelectrode in PEC system. However, the fast photogenerated carrier recombination and low visible light utilization of TNAs restrict practical application of PEC technology for organic pollutant degradation. In this work, the graphitic carbon nitride (g-C3N4) and reduced graphene oxide (rGO) were loaded on TNAs surface to prepare ternary photoelectrode (rGO/g-C3N4/TNAs) for PEC degradation of m-chloronitrobenzene (m-CNB) under visible light. The surface structure and composition analysis revealed that rGO and g-C3N4 were successfully deposited on TNAs surface. The good light absorption capacity of g-C3N4 and good conductivity of rGO inhibited the photogenerated carrier recombination of TNAs and g-C3N4. The rGO/g-C3N4/TNAs prepared with 60 mg/L graphene oxide (rGO/g-C3N4/TNAs-60) possessed wider visible-light absorption range, higher carrier density and photoconversion efficiency than other as-prepared photoelectrodes, which promoted PEC degradation efficiency of m-CNB. The cyclic degradation experiment indicated that rGO/g-C3N4/TNAs-60 photoelectrode had good reusability and stability. The radical scavenging experiments and electron paramagnetic resonance (EPR) spectra demonstrated that OH, O2– and h+ were major active species, and e− was auxiliary species for PEC degradation of m-CNB by rGO/g-C3N4/TNAs-60. The degradation pathways of m-CNB were proposed according to gas chromatography mass spectra and density functional theory calculation. The comprehensive toxicity of m-CNB was relieved after PEC degradation according to the toxicity prediction.

Regulation of Photovoltaic Response in ZSO-Based Multiferroic BFCO/BFCNT Heterojunction Photoelectrodes via Magnetization and Polarization

Multiferroic devices have attracted renewed attention in applications of photovoltaic devices for their efficient carrier separation driven by internal polarization, magnetization, and above-bandgap generated photovoltages. In this work, Zn2SnO4-based multiferroic Bi6Fe1.6Co0.2Ni0.2Ti3O18/Bi2FeCrO6 (BFCNT/BFCO) heterojunction photoelectrodes were fabricated. Structural and optical analyses showed that the bandgap of the spinel Zn2SnO4 is ∼3.1 eV while those of Aurivillius-type BFCNT and double-perovskite BFCO are 1.62 and 1.74 eV, respectively. Under the simulated AM 1.5G illumination, the as-prepared photoelectrodes delivered a photoconversion efficiency (η) of 3.40% with a short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) of 10.3 mA·cm-2, 0.66 V, and 50.4%, respectively. Analyses of adjustment of an applied electric and magnetic field on photovoltaic properties indicated that both magnetization and polarization of multiferroics can effectively tune the built-in electric field and the transport of charge carriers, providing a new idea for the design of future high-performance multiferroic oxide photovoltaic devices.

In2O3 anchored Fe2O3 nanorod arrays for enhanced photoelectrochemical performance

Fe2O3 is supposed to be one of the most promising photoanode materials. In terms of charge collection and transfer efficiencies, one-dimensional nanostructure arrays exhibit superior performance with great application potential in different fields. In the articles, Fe2O3 nanorod arrays (Fe2O3NRA) have been fabricated on the conductive fluorine-doped tin dioxide glasses by the hydrothermal method, In2O3 with different times cycles anchored Fe2O3NRA photoelectrode was also prepared by a simple dip-coating process. The structure, morphology, crystalline and optical property of the as-prepared photoelectrode were characterized by X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, etc. The photoelectrochemical performance of the samples was investigated under visible light irradiation. A highest photocurrent density of 23 μA/cm2 at 1.23 V (versus the reversible hydrogen electrode) is obtained for the In2O3 with 4 times cycle anchored Fe2O3NRA photoelectrode in a 1 M Na2SO4 aqueous solution. The maximum applied bias photon-to-current efficiency is observed for the In2O3 with 4 times cycle anchored Fe2O3NRA photoelectrode with values 0.0033%. The results indicated that the appropriate decoration amount of In2O3 nanoparticles significantly hinders the recombination process of electron-hole pairs and improves the separation efficiency of photogenerated charge carriers of Fe2O3NRA.

Integrated heterostructure of PZT/CdS containing the synergistic effect between heterojunction structure and ferroelectric polarization for photoelectrochemical applications

Ferroelectric photoelectrodes such as Pb(Zr0.2Ti0.8)O3 (PZT), with the high built-in electric for the separation of photoexcited carriers, are ideal candidates for photoelectrochemical (PEC) water splitting. However, the large bandgap and the poor conduction have limited the PEC performance of PZT photoelectrodes to date. To conquer these intrinsic drawbacks, we proposed the designed photoelectrode based on ferroelectric PZT film and surface decoration of discontinuous CdS nanoparticles toward enhanced PEC water splitting. More specifically, the ferroelectric PZT substrate with a spontaneous ferroelectric polarization could effectively segregated the charge carriers that generated in the bulk of photoelectrode. Meanwhile, the electron-hole pairs near the interface of PZT film and CdS nanoparticle could be effectively separated and transferred on account of the resulted p-n junction. Besides, the limitations of PZT include wide band gap and poor conductivity can be conquered by decorated CdS nanoparticles, which not only play as an electron conductor to trap photoinduced electrons transferred from PZT but also enhance the solar light harvesting own to their narrow band gap. The as-prepared photoelectrodes exhibited an enhanced photocurrent density (at 0 V vs. Ag/AgCl), which was 11 times than that of pure PZT films. This work may provide a new strategy toward the rational design of high performance ferroelectric-based photoelectrodes.

Surface-Modified Titanium Dioxide Nanofibers with Gold Nanoparticles for Enhanced Photoelectrochemical Water Splitting

High-stability, high-efficiency, and low-cost solar photoelectrochemical (PEC) water splitting has great potential for hydrogen-energy applications. Here, we report on gold/titanium dioxide (Au/TiO2) nanofiber structures grown directly on a conductive indium tin oxide substrate, and used as photoelectrodes in PEC cells for hydrogen generation. The titanium dioxide nanofibers (TiO2 NFs) are synthesized using electrospinning, and are surface-modified by the deposition of gold nanoparticles (Au NPs) using a simple photoreduction method. The structure and morphology of the materials were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) of the Au NPs was investigated by ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy. The PEC properties of the as-prepared photoelectrodes were measured. The obtained photoconversion efficiency of 0.52% under simulated-sunlight illumination by a 150 W xenon lamp of the Au/TiO2 NFs structure with 15 min UV irradiation for Au NP deposition was the highest value from comparable structures. Working photoelectrode stability was tested, and the mechanism of the enhanced PEC performance is discussed.

Shape-dependent performance of gold nanocrystals supported on TiO2 for photoelectrochemical water oxidation under different radiations

A number of studies are documented for enhanced solar energy conversion of titanium dioxide (TiO2) by surface modification with gold (Au) nanostructures. Herein, Au nanocrystals of different geometry (spherical, cubes, triangles and wires) are synthesized and immobilized on TiO2 (bare and nitrogen–doped) surface. The shape–dependent performance of the as-prepared photocatalysts is evaluated by studying water oxidation, both under UV–visible and visible illuminations. As expected, a strong dependency of PEC performance on the shape of Au nanocrystals is discerned. Also, the trend of performance under UV–visible is different than that of visible radiation, suggesting a distinct charge transport mechanism. In addition, the photocatalytic performance increases under visible light while decreases under UV–visible with increasing Au loading. A schematic is proposed showing a likely interfacial electron transfer reaction between Au nanostructures and TiO2, depending on illuminating wavelength. The performance variation in the as-prepared photoelectrodes is correlated to particle size, optical properties and electrical conductivity.

Shape-dependent activity of anisotropic Ag nanostructures supported on TiO2 for the photoelectrocatalytic water oxidation

Herein, we report shape-dependent photoelectrocatalytic activity of Ag/Ag2O nanostructures supported on pristine or nitrogen-doped TiO2 (NTiO2). Isotropic (spherical) and anisotropic (cubic and triangular) nanocrystals of Ag/Ag2O nanocrystals were fabricated using complexing and surface directing agents. Microscopic images confirmed the formation of nanospheres (∼ 50–60 nm), nanocubes (∼ 50–70 nm), triangular nanoplates (∼ 40–60 nm). The X-ray photoelectron spectroscopy indicated the presence of metallic silver (Ag0) and oxidized silver (Ag+). The as-prepared photoelectrodes were illuminated by Ultraviolet–Visible (λ = 300–600 nm) or visible radiations (λ = > 420 nm), and photoelectrochemical oxidation of water was examined. The findings indicate a significant correlation in the shape of Ag/Ag2O nanostructures, the incident wavelength, and the photoelectrochemical performance. In addition, different performance trend was discerned under Ultraviolet–Visible and visible excitations with respect to the amount of deposited Ag/Ag2O. The variation in activity observed with different shapes of Ag/Ag2O was correlated to enhanced optical property, arising due to the anisotropic structure, and electrical conductivity.

Dye-sensitized photoelectrochemical water oxidation through a buried junction

Water oxidation has long been a challenge in artificial photosynthetic devices that convert solar energy into fuels. Water-splitting dye-sensitized photoelectrochemical cells (WS-DSPECs) provide a modular approach for integrating light-harvesting molecules with water-oxidation catalysts on metal-oxide electrodes. Despite recent progress in improving the efficiency of these devices by introducing good molecular water-oxidation catalysts, WS-DSPECs have poor stability, owing to the oxidation of molecular components at very positive electrode potentials. Here we demonstrate that a solid-state dye-sensitized solar cell (ss-DSSC) can be used as a buried junction for stable photoelectrochemical water splitting. A thin protecting layer of TiO2 grown by atomic layer deposition (ALD) stabilizes the operation of the photoanode in aqueous solution, although as a solar cell there is a performance loss due to increased series resistance after the coating. With an electrodeposited iridium oxide layer, a photocurrent density of 1.43 mA cm-2 was observed in 0.1 M pH 6.7 phosphate solution at 1.23 V versus reversible hydrogen electrode, with good stability over 1 h. We measured an incident photon-to-current efficiency of 22% at 540 nm and a Faradaic efficiency of 43% for oxygen evolution. While the potential profile of the catalyst layer suggested otherwise, we confirmed the formation of a buried junction in the as-prepared photoelectrode. The buried junction design of ss-DSSs adds to our understanding of semiconductor-electrocatalyst junction behaviors in the presence of a poor semiconducting material.

N,Cu-Codoped Carbon Nanosheet/Au/CuBi2O4 Photocathodes for Efficient Photoelectrochemical Water Splitting

In this paper, we successfully fabricated CuBi2O4 and nitrogen,cuprum-codoped carbon nanosheet (N,Cu–C) heterostructure connected by Au nanoparticles, which was applied in photoelectrochemical (PEC) water splitting for the first time. The Au nanoparticle in situ decoration on the material surface was carried out by simple photoreduction. Owing to the plasmon resonance effect and low charge transfer resistance of Au nanoparticles, CuBi2O4/Au/N,Cu–C hybrids exhibited enhanced photocurrent compared with traditional CuBi2O4 and CuBi2O4/N,Cu–C. Typically, the as-prepared photoelectrode displayed an optimal photoelectric conversion (0.17%, at 0.4 V vs RHE) and PEC photocurrent (0.31 mA cm–2, at 100 mW cm–2 and 0.5 V vs RHE) that is about 5 times that of pure CuBi2O4. The enhanced PEC water splitting ability can be mainly attributed to the N,Cu-codoped carbon nanosheets as the passivation layer and Au nanoparticles as an electron relay for electron transport and a plasmonic photosensitizer for increased light ab...

A down-shifting Eu3+-doped Y2WO6/TiO2 photoelectrode for improved light harvesting in dye-sensitized solar cells.

Y1.86Eu0.14WO6 phosphors were prepared using a solid-state reaction method. Their optical properties were analysed, and they was mixed with TiO2, sintered, and used as a photoelectrode (PE) in dye-sensitized solar cells (DSSCs). The as-prepared photoelectrode was characterized by photoluminescence spectroscopy, diffuse reflectance, electrochemical impedance spectroscopy (EIS) and X-ray diffraction. The photoelectric conversion efficiency of the DSSC with TiO2:Y1.86Eu0.14WO6 (100:2.5) was 25.8% higher than that of a DSCC using pure TiO2 as PE. This high efficiency is due to the ability of the luminescent material to convert ultraviolet radiation from the sun to visible radiation, thus improving the solar light harvesting of the DSSC.

Highly ordered TiO2 nanotube arrays wrapped with g-C3N4 nanoparticles for efficient charge separation and increased photoelectrocatalytic degradation of phenol

Novel graphitic carbon nitride nanoparticles (NPs)-wrapped TiO2 nanotube arrays (NTAs) (g-C3N4/TiO2) were fabricated by a two-step method including an electrochemical anodization technique followed by impregnation under vacuum using urea as precursor. The as-prepared photoelectrode exhibited outstanding photoelectric properties and excellent photelectrocatalytic (PEC) performance for the degradation of phenol under stimulated solar light, which was due to the enhanced light absorption property and improved charge separation efficiency. The introduction of g-C3N4 NPs strongly decreased the charge transfer resistance and boosted the charge separation efficiency of TiO2. The optimum ratio of the g-C3N4/TiO2 yielded a pronounced 4.18-fold higher photocurrent density than TiO2. Besides, the combination of g-C3N4 NPs could negatively shift for the flat band potential of TiO2, resulting in an enhanced reduction property for the photoelectrocatalytic degradation of organic pollutants. The PEC process for the degradation of phenol over g-C3N4/TiO2 was much higher than the sum of photocatalytic (PC) and electrocatalytic (EC) processes indicating that a photoelectric synergy was achieved on the as-prepared photoelectrode and resulting in an improved PEC performance for the composite photoelectrode.

Fabrication of MnO2/TiO2 nano-tube arrays photoelectrode and its enhanced visible light photoelectrocatalytic performance and mechanism

Abstract MnO 2 /TiO 2 nano-tube arrays (MnO 2 /TiO 2 NTAs) photoelectrode was synthesized through anodization and electrodeposition, followed by the prepared conditions optimized. Subsequently, structures of the as-prepared photoelectrodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Besides, the light absorption capacities and photoelectrochemical (PECH) properties were investigated through UV–vis diffuse reflectance spectrophotometer (UV–vis DRS), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS). In addition, these photoelectrodes were used for the photoelectrocatalytic (PEC) degradation of methylene orange (MO) under Xenon lamp irradiation. Moreover, the enhanced PEC mechanism was further confirmed through scavengering effect and photoluminsecence (PL) spectra. Results presented that the highly ordered TiO 2 nano-tube arrays photoelectrodes processed a uniform sizes of inner diameter of 300 nm and well thickness of 60 nm with MnO 2 nanoparticles successfully deposited. Furthermore, it was found that these novel MnO 2 /TiO 2 NTAs photoelectrodes could not only red-shift the light absorption to visible region between 400 nm and 700 nm, but also significantly enhance the generation of hydroxyl radicals ( OH) which played an important role in the PEC system. Noticeably, the MnO 2 /TiO 2 NTAs photoelectrodes made in the optimized conditions exhibited much higher PEC activity toward MO degradation with the efficiency up to 95.2% within 1 h when external potential (+2.0 V) was applied. More importantly, these novel MnO 2 /TiO 2 NTAs photoelectrodes proved to have excellent stability and reusability that would have great potentials for organic contaminants degradation in wastewater treatment.

Fabrication and photoelectrochemical properties of silicon nanowires/g-C3N4 core/shell arrays

A photoelectrochemical (PEC) cell made of metal-free carbon nitride (g-C3N4) @siliconnanowire(Si NW) arrays (denoted as Si NWs/g-C3N4) is presented in this work. The as-prepared photoelectrodes with different mass contents of g-C3N4 have been synthesized via a metal-catalyzed electroless etching (MCEE), liquid atomic layer deposition (LALD) and annealing methods. The amount of g-C3N4 on the Si NW arrays can be controlled by tuning the concentration of the cyanamide solution used in the LALD procedure. The dense and vertically aligned Si NWs/g-C3N4 core/shell nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In comparison with FTO/g-C3N4 and Si NW samples, the Si NWs/g-C3N4 samples showed significantly enhanced photocurrents over the entire potential sweep range. Electrochemical impedance spectroscopy (EIS) was conducted to investigate the properties of the charge transfer process, and the results indicated that the enhanced PEC performance may be due to the increased photo-generated interfacial charge transfer between the Si NWs and g-C3N4. The photocurrent density reached 45μA/cm2 under 100mW/cm2 (AM 1.5G) illumination at 0V (vs. Pt) in neutral Na2SO4 solution (pH∼7.62). Finally, a systematical PEC mechanism of the Si NWs/g-C3N4 was proposed.

Construction of graphite/TiO2/nickel foam photoelectrode and its enhanced photocatalytic activity

Graphite/TiO2/nickel foam photoelectrode was constructed through a modified sol-gel method, followed by coating procedure. Morphology, structure and optical property of the as-prepared photoelectrode was characterized via transmission electron microscopy (TEM), scanning electrons microscopy (SEM), X-ray photoelectron microscopy (XPS), X-ray diffraction (XRD) and UV–vis diffuse reflection spectroscopy (DRS). Results indicated that nickel foam framework was partly covered by graphite/TiO2 and the crystallite sizes of anatase TiO2 were found to be about 10nm.C elements were incorporated into the lattice of TiO2 nanoparticles through replacing titanium atom. Graphite/TiO2/nickel foam photoelectrode showed the enhancement of light absorption in entire UV–vis regions. Besides, the photoelectrochemical performances of the graphite/TiO2/nickel foam electrode were studied by transient photocurrent response (TPR), open circuit voltage (OCV) and electrochemical impedance spectroscopy (EIS). Moreover, photodecomposition properties of the electrode were evaluated by the generation of hydroxyl (OH) radicals, photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of methyl orange (MO). The graphite/TiO2/nickel foam electrode revealed high transient photogenerated current of 0.054mAcm−2, open circuit photovoltage of −0.32mVcm−2, yield of OH radicals, PC activity of 85.1% and PEC activity of 99.8% for removal of MO. The improved PEC efficiency could be mainly ascribed to the coupled graphite, nickel foam support and applied bias voltage, which could not only enhance the UV–vis light absorption, but also accelerate the charges separation and transfer.

Photoelectrocatalytic Glucose Oxidation to Promote Hydrogen Production over Periodically Ordered TiO2 Nanotube Arrays Assembled of Pd Quantum Dots

The development of highly efficient and low-cost approaches for catalytic hydrogen production from renewable energy is of tremendous importance for a truly sustainable hydrogen-based energy carrier in future life. Herein, the probability of utilizing solar light to product hydrogen from biomass derivative, glucose, was systematically demonstrated by using the periodically ordered TiO2 nanotube arrays (TNTAs) assembled of Palladium quantum dots (Pd QDs), i.e. Pd QDs@ TNTAs as photoanode. The results showed that remarkably increased photocurrent density was obtained in the glucose solution compared to the pure KOH electrolyte over as-prepared photoelectrode, which indicated that the glucose could be faster oxidized than water oxidation, and thus could promote the hydrogen production on Pt cathode. The yield of hydrogen production from glucose oxidation reached as high as 164.8μmolcm−1 over Pd QDs@TNTAs photoanode and Pt cathode system (denoted as Pd QDs@TNTAs/Pt) under the solar light irradiation for 6h, which was about 15 times higher than that from pure water splitting. The superior hydrogen production performance could be attributed to the less endergonic process of the glucose oxidation than water, as well as the efficient synergistic photoelectrocatalytic (PEC) glucose oxidation over Pd QDs@TNTAs photoanode which possesses excellent photoelectrochemical performance and structure characteristics. Moreover, a probable mechanism for the PEC hydrogen production from biomass derivatives oxidation was proposed and discussed.

Hematite photo-electrodes with multiple ultrathin SiOx interlayers towards enhanced photoelectrochemical properties

Fe2O3 photo-electrodes with multiple ultrathin SiOx interlayers were prepared by a pulsed laser deposition method. The as-prepared photo-electrode showed a high photocurrent density of 1.13mA/cm2 at 0.6V vs. Ag/AgCl under a simulated solar irradiation (AM 1.5, 75mW/cm2 at 350nm–800nm). The enhancement of the photoelectrochemical properties should be due to the improved electron-hole migration inside the photo-electrode, which is caused by the import of multiple ultrathin SiOx interlayers.