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Reducing the reaction barrier on the photoelectrode surface and increasing the water oxidation power of the sample surface are the key issues to improve photoelectrochemical water splitting performances.

CoFe-NiOOH is developed for the first time as a ternary polymetallic surface oxygen evolution cocatalyst to enhance the photoelectrochemical (PEC) water splitting performance of BiVO4-based photoan...

By investigating photoelectrochemical (PEC) performance of p and n-type Cu2O, we do an exploratory study on dual-photoelectrode tandem PEC cell consisting of p-Cu2O/Pt photocathode and n-Cu2O/Co–Pi photoanode for the first time. Benefiting from electron capture (Pt) and hole transfer (Co–Pi) layers, the photoelectrodes have better charge separation efficiency and faster charge transfer kinetics. The p-Cu2O/Pt||n-Cu2O/Co–Pi PEC cell finally achieves an unassisted photocurrent density of 0.09 mA/cm2 after illumination for 1000 s, which preliminarily confirms the viewpoint of unassisted overall water splitting. We then anticipate this work can provide a novel platform for the design and fabrication of various PEC energy conversion devices with excellent performance.

The two-dimensional semiconductor photocatalytic material has excellent photocatalytic H2 evolution activity. In order to further improve the hydrogen production activity of g-C3N4, this study improved the preparation process of g-C3N4 and obtained a new photocatalyst (name H-CN) with a higher absorption range, larger specific surface area, and faster hydrogen production activity. Compared with the originally prepared g-C3N4, the H-CN absorption range has been improved, and the utilization of visible light has reached 650 nm. When the doping amount of Pt cocatalyst was 1.0 wt%, the H-CN demonstrates excellent photocatalytic hydrogen production activity, with a hydrogen production rate of 4.3 mmol h−1·g−1, which was 7.0 times higher than that pure 1.0 wt% Pt/g-C3N4. The fluorescence spectroscopy of H-CN showed better separation of carriers and longer lifetime. This study has guiding significance for the preparation of subsequent ultra-thin nanosheet photocatalysts and the establishment of high-efficiency photocatalytic systems.

A strategy is proposed for modifying BiVO4 photoanode with CoNiO2 as a novel water oxidation cocatalyst to enhance PEC water splitting performance. The results show that CoNiO2 has the following functions: reducing photogenerated charge recombination centers; providing trapping sites to promote charge separation; improving the stability of the overall system; providing more active sites; and offering a lower overpotential. The BiVO4/CoNiO2 photoanode has a higher photocurrent density (1.16 mA cm-2 at 1.23 V vs. RHE), a lower onset potential (∼0.06 V vs. RHE), a larger IPCE (34.37%) and ABPE (0.163%), better stability and good rates of hydrogen evolution (0.0148 μmol cm-2 min-1) and oxygen evolution (0.0076 μmol cm-2 min-1). The strategy provides promising prospects for achieving efficient PEC water splitting performance using water oxidation cocatalysts.

In this work, AgInS2 photoelectrodes doped with Ga element and deposited Co–Pi co–catalyst have been prepared on FTO substrates by hydrothermal and electrochemical deposition methods. In photoelectrochemical (PEC) measurements, the photocurrent density of AgInS2/Ga5%/Co–Pi photoelectrodes (2.18 mA/cm2 at 1.2 V vs. RHE) is about 3.25 times higher than that of pure AgInS2 photoelectrodes (0.67 mA/cm2 at 1.2 V vs. RHE). The enhanced PEC performance could be ascribed to the improved light absorption by doping Ga element and fast charge separation by depositing Co–Pi co–catalyst. This work highlights that doping appropriate metal element and loading co-catalyst to synergistically modify photoelectrodes are practicable approach for PEC water splitting.

In this paper an easy and mild solution-processed method is introduced to prepare extra sodium (Na) doped Cu2ZnSnS4 (CZTS) films on Mo-coated soda-lime glasses. Through this method, the Na-doping concentration can be adjusted at the range from 3.9% to 5.4% continuously. By extra Na doping through solution process, the grain size of CZTS particles was enlarged apparently without introducing any impurity phase. More excitingly, the photoluminescence (PL) spectrum indicates that high Na-doping concentration has the strong suppression ability on the band-gap recombination of CZTS films. The carrier lifetime is promoted from 2.1 ns to 2.83 ns. CZTS thin film solar cell with 4.8% Na-doping concentration shows the best performance.

The photoelectrochemical (PEC) water splitting properties can be enhanced by broadening the light absorption region and improving the separation of photogenerated carriers. In this paper, a novel ZnO/In2S3/Co–Pi ternary composite photoanode system is provided, by building the ZnO/In2S3 heterojunction to broaden the light absorption region and improve the separation and transfer of photogenerated electron–hole pairs in bulk, and by using the Co–Pi cocatalyst to increase the separation of photogenerated electron–hole pairs between the ZnO/In2S3 heterojunction surface and electrolyte. This ternary composite photoanode system exhibits a negative shifted onset potential and a higher photocurrent density of about 2.4 mA/cm2 at 1.23 V (vs. RHE), which is 3 and 2.18 times compared with bare ZnO nanorod and ZnO/In2S3 heterojunction, respectively. The results show that the ZnO/In2S3/Co–Pi ternary composite photoanode has an excellent potential application for PEC water splitting.

In order to improve the water splitting efficiency of CuInS2 in a photoelectrochemical (PEC) cell, the novel CuInS2/Sb2S3 heterostructure photocathodes modified with Pt noble metal co-catalyst were prepared on the ITO substrate by the hydrothermal and electrochemical deposition method for the first time. The mechanism of the synthesis reaction for the CuInS2/Sb2S3 and CuInS2/Sb2S3/Pt were investigated. With the photoelectrochemical measurements, the photocurrent density of CuInS2/Sb2S3/Pt photoelectrode (−2.48 mA/cm2 at −0.6 V vs. RHE) is about 3.13 times relatively higher than that of the corresponding the pure CuInS2 photoelectrode (−0.79 mA/cm2 at −0.6 V vs. RHE). The excellent PEC behaviors profit from the modification by Sb2S3 that forms the heterostructure which broadens the response of visible light and increases the separation and transfer of photo-generated carriers. Moreover, after introducing Pt co-catalyst onto the surface of CuInS2/Sb2S3 photoelectrode, photo-generated electrons can be captured quickly which further effectively promotes the separation of photo-generated carriers and greatly improve the PEC performance. This work manifests that the structure of CuInS2/Sb2S3/Pt photocathodes has a guiding suggestion to provide a promising approach to designing a highly stabilized efficient device for photoelectrochemical water splitting.

Earth-abundant and non-toxicity quaternary chalcogenide Cu2SrSnS4 is prepared by a facial ball-milling method. Its formation is revealed to be from the reaction between Cu2SnS3 and SrS at 600 °C. The bandgap of the prepared Cu2SrSnS4 film is speculated around 1.78 eV according to absorption test. The carrier lifetime of the prepared Cu2SrSnS4 film is about 2.06 ns. The photocurrent density of the Cu2SrSnS4 film is about 150 μA cm−2 at −670 mV bias vs Ag/AgCl electrode and it repeats after 10 cycles of 1000 s. Its notable generation of photocurrent and photoelectrochemical stability indicates its potential for photoelectric conversion application.

A strategy is proposed for modifying BiVO

The two-dimensional semiconductor photocatalytic material has excellent photocatalytic H

It is of great significance to explore new preparation methods and control the morphology and proportion of metal ions for the photoelectrochemical (PEC) water splitting of ternary sulfide photoelectrode. In this paper, the network-like CuInS2 film photocathodes were firstly prepared by hydrothermal growth method. The effects of different [Cu2+]/[In3+] molar ratios and concentrations of growth solution on CuInS2 films were investigated in detail. The mechanism of the synthetic reaction was studied. The best PEC photocurrent density of the CuInS2 film photoelectrode is − 0.81 mA/cm2 at − 0.6 V versus RHE when the [Cu2+]/[In3+] molar ratio is 0.4, the growth solution concentration is 8 mmol/L CuCl2·2H2O, 20 mmol/L InCl3·4H2O and 60 mmol/L C2H5NS. For the purpose of further improving photoelectrochemical properties of CuInS2 thin films, the Pt co-catalyst was loaded. The synthesized CuInS2–Pt thin film yielded a photocurrent density for − 1.92 mA/cm2 at − 0.6 V versus RHE due to the fast photogenerated electrons capture ability of Pt co-catalyst. The method of constructing photoelectrode film and the co-catalyst mechanism contributes to a sensational way for PEC water splitting of sulfide.

The BaTiO 3 (BTO) / CoFe 2 O 4 (CFO) / BaTiO 3 (BTO) laminated ceramic composites were prepared via spark plasma sintering (SPS). The ceramic composites were highly dense with clear boundaries between the three layers. The short time and low temperature required for densification during the SPS process diminish the possibility for unwanted reactions to occur. The BTO/CFO/BTO laminated ceramic composites exhibit excellent ME properties including: (1) maximal ME voltage coefficient as high as ~ 1.0 V/Oe cm; (2) obvious AC magnetic field frequency response and sensitivity from 10 2 to 10 7 Hz; (3) perfect ME anisotropy matches well with the theoretical fitting curve; (4) giant transverse ME voltage coefficient as large as ~ 4.1 V/Oe cm at resonance frequency of ~ 10 5 Hz. It is possible to fabricate several kinds of ME function devices with the BTO/CFO/BTO laminated ceramics prepared in this work.

The pure-phase BiFeO3 crystals with distinguished micro-morphologies were successfully prepared by a novel coprecipitation-hydrothermal collaborative synthesis method. Hydroxylation technique was innovatively employed to hydroxylate BiFeO3 samples. XPS and PL spectra proved that hydroxylation treatment indeed introduced more ·OH radicals on the surfaces of the BiFeO3 samples. Sample E (hydroxylated BiFeO3 ultra-thin slices) showed the highest photocatalytic activity. Hydroxylated BiFeO3 prepared in this work also showed high activities in water photo-oxidation reactions for producing oxygen gas. All hydroxylated samples showed notably enhanced photocatalytic activities due to the large specific surface areas, strong visible light responses, diminished recombination rates of the photo-excited carriers and excess ·OH radicals introduced by surface hydroxylation. All BiFeO3 samples showed good photochemical stabilities for reusage. This work provides valuable contributions in the future preparations and applications for BiFeO3 photocatalysts.

Expanding the optical response range and improving the photogenerated carrier separation rate are critical to increasing the efficiency of photoelectrochemical (PEC) water splitting. In this paper, a ZnO/Cu2O/Co-Pi heterojunction was successfully fabricated for photoelectrochemical (PEC) water splitting. As a narrow band semiconductor, Cu2O can extend the absorption range of solar spectra. Co-Pi plays the role of a hole-trapping cocatalyst to accelerate the water oxidation reaction at the electrode and electrolyte interfaces. This complex ZnO/Cu2O/Co-Pi photoanode moves the origin potential in a negative direction, and displays an improved photocurrent density of 1.58 mA cm−2 at 1.23 V vs. RHE, which is 1.08 times that of a ZnO/Cu2O heterojunction and 2.03 times that of pure ZnO. The efficient PEC performances of the ZnO/Cu2O/Co-Pi photoanode are caused by the broader light absorption and higher photogenerated carrier separation rate. This study proved that the simultaneous reaction of the heterojunction and cocatalyst has great prospects for application in efficient photoelectrochemical (PEC) water splitting photoelectrode systems.

Novel CaBi6O10 films were prepared via a simple dip-coating method and applied as a photoanode in photoelectrochemical (PEC) water splitting for the first time. Herein, the detailed growth mechanism of CaBi6O10 has been discussed. The optical absorption of CaBi6O10 was also investigated, and the results indicated that its ideal band-gap energy (∼2.3 eV) causes it to respond to visible light. Additionally, the morphology and thickness of the films were characterized in detail. PEC measurements showed that this CaBi6O10 photoanode exhibits high photoelectrochemical activity based on the optimal pH value of the precursor solution and thickness of the film; its photocurrent density is as high as 0.39 mA cm−2 at 1.23 V vs. RHE under simulated sunlight. Moreover, the CaBi6O10 photoelectrode displays a very stable photoelectric property under illumination. The excellent PEC performance is attributed to the excellent light absorbance, broad photoresponse range, and efficient photogenerated electron–hole pair separation of CaBi6O10. These results demonstrate that CaBi6O10 is a promising photoanode for solar water splitting.

The light absorption range of semiconductor materials and the separation rate of electron–hole pairs are significant challenge in photoelectrochemical (PEC) water splitting. In this work, we first prepared a ternary heterojunction of ZnO/CuO/Ag by chemical bath deposition method. The formation of the heterojunction can improve the absorption range and increase the electron–hole pairs’ separation rate, and the loading of plasmonic Ag nanoparticles can expand the absorption range of visible light and generate more photogenerated electrons through surface plasmon resonance (SPR). The ZnO/CuO/Ag heterojunction photoelectrode reveals an efficient photocurrent density of 3.45 mA cm−2 at 1.23 V vs. RHE, which is 3.08 and 1.12 times higher compared with ZnO and ZnO/CuO photoelectrode, respectively. This study shows that the simultaneous reaction of heterojunction and plasmonic noble metal nanoparticles can synergistically improve the photoelectric properties of photoanodes in photoelectrochemical water-splitting system.

The Cu 2 ZnSnS 4 thin film was prepared by a facile solution method without vacuum environment and toxic substance. The formation mechanism of the film was studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman scattering measurements. Through cyclic voltammetry and photo-electricity tests, the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitized solar cell was also studied. The results show that the mixed precursor solution mainly consists of Cu 2 SnS 3 nanoparticles and Zn ions. After 550 °C annealing process on the precursor film prepared from the mixed solution, Cu 2 ZnSnS 4 thin film is obtained. Besides, it is found that the prepared Cu 2 ZnSnS 4 thin film has the electrocatalytic activity toward the redox reaction of I 3 − /I − and the dye-sensitized solar cell with the prepared Cu 2 ZnSnS 4 thin film as the counter electrode achieves the efficiency of 1.09%.

In this work, a thin layer of bismuth (Bi) is pre-deposited on the Mo-coated glass before the deposition of the Cu2ZnSnS4 to optimize the properties of the Cu2ZnSnS4 thin film and the performance of corresponding solar cell. It is found that the pre-deposition of Bi leads to the improvement in the crystallinity of synthesized Cu2ZnSnS4 film as evidenced by large grain sizes and less grain boundaries. Photoluminescence measurement indicates that the recombination in the film is inhibited as the reduction of the boundaries which is always regarded as the recombination centers of the carriers. Besides, the reaction of Zn into CZTS lattice is promoted with the decrease of the second phase ZnS. In addition, the inserted Bi layer blocks the diffusion of S atoms into Mo with the reduced thickness of MoS2 at CZTS|Mo interface. It decreases the cell series resistance. Because of the improvements above, the performance of the cell with pre-deposited Bi is boosted.

The novel concept of introducing intermediate band into the mesoporous TiO2 backbone of dye-sensitized solar cells (DSSCs) is proposed to take full advantage of the sunlight and enhance the power conversion efficiency. Nominal trace amount W-doped TiO2 nanocrystralline films were prepared with the purpose of forming intermediate band in the bandgap of TiO2. A notable improvement of the device performance was obtained when N-type W-doped TiO2 films were applied as the photoanode of DSSCs. The short-circuit current density (Jsc) increased from 12.40 mA cm–2 to 15.10 mA cm–2, and the conversion efficiency increased from 6.64 to 7.42% when nominal 50 ppm (ppm) W-doped TiO2 was adopted.

MoS2 nanodot decorated In2S3 nanoplates were successfully synthesized via a modified one-pot method. The In2S3/MoS2 heterojunction nanocomposite exhibits superior optical and photoelectrochemical performance to the bare ones, owing to the synergistic effect.

A Cu 2 ZnSnS 4 (CZTS) ultrathin film counter electrode (CE) was prepared in situ by the sol–gel method. As the film was only 200 nm thickness, it showed a degree of transparence. The dye-sensitized solar cell (DSSC) with the prepared CE was the bifacially active transparent cell, which exhibited η of 5.63% and 1.60% corresponding to front- and back-side illumination respectively. It showed improved performance compared to DSSC with Pt CE, Electrochemical impedance spectroscopy (EIS) and Cyclic voltammetry (CV) measurements indicated the CZTS ultrathin film CE had a superior electrocatalytic activity than Pt CE.

Alkaline metals doping is one of the approaches for achieving high efficiency Cu(In,Ga)Se2 (CIGS) solar cell. Recently, potassium doping helps to break the record efficiency of CIGS solar cell doped with sodium. In this paper, we have investigated how incorporation of potassium can influence the properties of Cu2ZnSnS4 (CZTS) thin film and the performance of resulting solar cell. Our results showed that K doping can enhance the (112) preferred orientation, increase the grain size and reduce the second phase ZnS of the CZTS thin films. After K doping, despite of some drop of Voc for CZTS thin film solar cells, the Rs is decreased and the Jsc is improved markedly, and the solar cell efficiency is boosted.