Spatial engineering of a Co(OH)x encapsulated p-Cu2S/n-BiVO4 photoanode: simultaneously promoting charge separation and surface reaction kinetics in solar water splitting

2019 ◽  
Vol 7 (12) ◽  
pp. 6747-6752 ◽  
Author(s):  
Bing He ◽  
Yang Wang ◽  
Xueqin Liu ◽  
Yinchang Li ◽  
Xiaoqin Hu ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Water Splitting ◽  
Charge Separation ◽  
Surface Reaction ◽  
Separation Efficiency ◽  
Photocurrent Density ◽  
Solar Water ◽  
Solar Water Splitting ◽  
Charge Separation Efficiency ◽  
Surface Reaction Kinetics

An ultrathin Co(OH)x coated p-Cu2S/n-BiVO4 heterojunction photoanode with improved charge separation efficiency was prepared, showing a photocurrent density of 3.51 mA cm−2.

Surface Engineering of Metal Oxide Photoelectrodes for Improved Band Alignment in Solar Water Splitting Cells

2016 ◽  
Vol 879 ◽  
pp. 832-837 ◽  
Author(s):  
Soong Leong Sim ◽  
Ye Ru Liu ◽  
Ying Woan Soon ◽  
James Robert Jennings
Keyword(s):  
Metal Oxide ◽  
Water Splitting ◽  
Charge Separation ◽  
Diffusion Length ◽  
Separation Efficiency ◽  
Electron Diffusion ◽  
Solar Water ◽  
Solar Water Splitting ◽  
Charge Separation Efficiency ◽  
Electron Diffusion Length

Several earth-abundant transition-metal oxides (e.g. Fe2O3, CoO, and Cu2O) possessing suitable band gaps for solar water splitting exist, but energy level alignment is often sub-optimal, i.e. the conduction and valence bands do not straddle the water oxidation and reduction potentials. Here, using a nanocrystalline-TiO2-based photoelectrochemical cell as a model system, we investigate the effect of tuning the semiconductor energy levels by adding Li+ ions to the electrolyte. The effect of LiClO4 addition on band edges, interfacial recombination resistance, electron diffusion length, and charge-separation efficiency were quantified by impedance spectroscopy and analysis of incident photon-to-current efficiency spectra. We find that the TiO2 band edges are shifted toward positive potentials by the addition of Li+, and that this increases the apparent electron diffusion length without affecting the charge-separation efficiency, most likely due to a change in the driving force for O2 reduction. These results should prove useful in the modeling and optimization of solar water splitting cells employing metal oxide photoelectrodes.

Improved charge separation via Fe-doping of copper tungstate photoanodes

2015 ◽  
Vol 17 (15) ◽  
pp. 9857-9866 ◽  
Author(s):  
Divya Bohra ◽  
Wilson A. Smith
Keyword(s):  
Water Splitting ◽  
Charge Separation ◽  
Separation Efficiency ◽  
Fe Doping ◽  
Solar Water ◽  
Solar Water Splitting ◽  
New Methods ◽  
Copper Tungstate ◽  
Charge Separation Efficiency ◽  
Conversion Efficiencies

By doping CuWO4 photoanodes with Fe, the charge separation efficiency and incident photon-to-current conversion efficiencies have increased dramatically, leading to improvements in the fundamentally limiting processes in this material. These results offer new methods and insights into improved solar water splitting photoelectrodes.

Identifying dual functions of rGO in a BiVO4/rGO/NiFe-layered double hydroxide photoanode for efficient photoelectrochemical water splitting

2020 ◽  
Vol 8 (26) ◽  
pp. 13231-13240 ◽  
Author(s):  
Hua Chen ◽  
Songcan Wang ◽  
Jianzhong Wu ◽  
Xiacong Zhang ◽  
Jia Zhang ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Water Splitting ◽  
Layered Double Hydroxides ◽  
Oxygen Evolution Reaction ◽  
Surface Reaction ◽  
Photocurrent Density ◽  
Surface Reaction Kinetics ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Dual Functions

To enhance surface reaction kinetics for oxygen evolution reaction, nanoporous BiVO4 photoanodes are modified by rGO and NiFe-layered double hydroxides, leading to an enhanced photocurrent density of 3.26 mA cm−2 under AM 1.5 G illumination.

BiVO4 Nanostructures for Photoelectrochemical (PEC) Solar Water Splitting Applications

2019 ◽  
Vol 19 (11) ◽  
pp. 7427-7435 ◽  
Author(s):  
B. Jansi Rani ◽  
M. Praveenkumar ◽  
S. Ravichandran ◽  
G. Ravi ◽  
Ramesh K. Guduru ◽  
...  
Keyword(s):  
Water Splitting ◽  
Separation Efficiency ◽  
Sodium Dodecyl ◽  
Photocurrent Density ◽  
Flat Band ◽  
Solar Water Splitting ◽  
Charge Separation Efficiency ◽  
Crystalline Nature ◽  
Sds Surfactant ◽  
Pec Water Splitting

We reported a simple and economical SDS (sodium dodecyl sulfate) assisted BiVO4 solvothermal synthesis of BiVO4 nanostructures. The implementation of pristine and SDS assisted BiVO4 nanostructure as photoanode in photoelectrochemical (PEC) water splitting was investigated. The good crystalline nature, defects present in the material, recombination nature and vibrational properties of the synthesized BiVO4 nanostructures have been analyzed and confirmed by XRD, Raman, PL and FTIR studies. The constructed nanoflower oriented morphology combined with nanorods for SDS assisted BiVO4 have been examined by SEM studies. The optical band gap differences were observed as 2.35 and 2.31 eV for pristine and SDS assisted BiVO4 nanostructures respectively. The higher photocurrent density of 5.8 μA/cm2 at 0.5 V versus RHE with lower flat band potential of -0.75 V revealed for SDS assisted BiVO4 nanostructured photoanodes. Good conductivity, higher charge separation efficiency and 52% photocurrent retention under illumination was reported over 7200 s for the same efficient photoanode. These results suggested the substantial possibility of BiVO4 nanostructures synthesized by using SDS surfactant could be utilized as efficient photoanodes for PEC water splitting applications.

Novel Black BiVO 4 /TiO 2− x Photoanode with Enhanced Photon Absorption and Charge Separation for Efficient and Stable Solar Water Splitting

2019 ◽  
Vol 9 (27) ◽  
pp. 1901287 ◽  
Author(s):  
Zhangliu Tian ◽  
Pengfei Zhang ◽  
Peng Qin ◽  
Du Sun ◽  
Shaoning Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Charge Separation ◽  
Photon Absorption ◽  
Solar Water ◽  
Solar Water Splitting

A Three-Dimensional ZnO/CdS/NiFe Layered Double Hydroxide Photoanode Coupled with a Cu2O Photocathode in a Tandem Cell for Overall Solar Water Splitting

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950146
Author(s):  
Jia Liu ◽  
Yinghua Zhang ◽  
Zhiming Bai ◽  
Zhian Huang ◽  
Yukun Gao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Layered Double Hydroxide ◽  
Three Dimensional ◽  
Photocurrent Density ◽  
Cds Nanoparticles ◽  
Zero Bias ◽  
Tandem Cell ◽  
Solar Water ◽  
Solar Water Splitting ◽  
Double Hydroxide

An integrated tandem photoelectrochemical (PEC) cell, composed of a three-dimensional (3D) ZnO/CdS/NiFe layered double hydroxide (LDH) core/shell/hierarchical nanowire arrays (NWAs) photoanode and a [Formula: see text]-Cu2O photocathode, was designed for unassisted overall solar water splitting in this study. The optical and photoelectrochemical characteristics of ZnO-based photoanodes and Cu2O photocathode were investigated. The results show that ZnO/CdS/NiFe LDH nanostructures offer significantly enhanced performances with a photocurrent density reaching 5.8[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] at 0.9[Formula: see text]V and an onset potential as early as 0.1[Formula: see text]V (versus RHE). The enhancement can be attributed to the existence of CdS nanoparticles (NPs) which boosts the light absorption in visible region and enhances charge separation. Moreover, the introduction of NiFe LDH nanoplates, with unique hierarchical mesoporous architecture, promotes electrochemical reactions by providing more active sites as co-catalyst. On the above basis, the ZnO/CdS/NiFe LDH–Cu2O two-electrode tandem cell system was established. At zero bias, the device shows a photocurrent density of 0.4[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] along with the corresponding solar-to-hydrogen (STH) conversion efficiency reaching 0.50%. Our results indicate that the tandem PEC cells consisting of metal–oxide–semiconductor photoelectrodes based on Earth-abundant and low-cost materials hold promising application potential for overall solar water splitting.

scholarly journals Recent Advances of Metal‐Oxide Photoanodes: Engineering of Charge Separation and Transportation toward Efficient Solar Water Splitting

Solar RRL ◽  
2020 ◽  
Vol 4 (8) ◽  
pp. 1900509 ◽  
Author(s):  
Mu Xiao ◽  
Bin Luo ◽  
Zhiliang Wang ◽  
Songcan Wang ◽  
Lianzhou Wang
Keyword(s):  
Metal Oxide ◽  
Water Splitting ◽  
Charge Separation ◽  
Solar Water ◽  
Solar Water Splitting ◽  
Recent Advances

scholarly journals Combinatorial Search for New Solar Water Splitting Photoanode Materials in the Thin-Film System Fe–Ti–W–O

2020 ◽  
Vol 234 (5) ◽  
pp. 867-885 ◽  
Author(s):  
Swati Kumari ◽  
Chinmay Khare ◽  
Fanxing Xi ◽  
Mona Nowak ◽  
Kirill Sliozberg ◽  
...  
Keyword(s):  
Thin Film ◽  
Water Splitting ◽  
Spin Coating ◽  
Photocurrent Density ◽  
Coated Sample ◽  
X Ray Diffraction ◽  
Film Library ◽  
X Ray ◽  
Solar Water ◽  
Solar Water Splitting

AbstractIn order to identify new solar water splitting photoanodes, Fe–Ti–W–O materials libraries were fabricated by combinatorial reactive co-sputtering and investigated by high-throughput characterization methods to elucidate compositional, thickness, and structural properties. In addition, photoelectrochemical measurements such as potentiodynamic photocurrent determination and open circuit potential measurements were performed using an automated scanning droplet cell. In the thin-film library, a quaternary photoactive region Fe30–49Ti29–55W13–22Ox was identified as a hit composition region, comprising binary and ternary phases. The identified region shows a distinct surface morphology with larger grains (∼200 nm) being embedded into a matrix of smaller grains (∼80–100 nm). A maximum photocurrent density of 117 μA/cm2 at a bias potential of 1.45 V vs. RHE in NaClO4 as an electrolyte under standard solar simulating conditions was recorded. Additional samples with compositions from the hit region were fabricated by reactive co-sputtering and spin coating followed by annealing. Synchrotron X-ray diffraction of sputtered Fe32Ti52W16Ox thin-films, annealed in air (600 °C, 700 °C, 800 °C) revealed the presence of the phases FeTiO3 and Ti0.54W0.46O2. The composition Fe48Ti30W22Ox from the hit region was fabricated by spin coating and subsequent annealing for a detailed investigation of its structure and photoactivity. After annealing the spin-coated sample at 650 °C for 6 h, X-ray diffraction results showed a dominant pattern with narrow diffraction lines belonging to a distorted FeWO4 (ferberite) phase along with broad diffraction lines addressed as Fe2TiO5 and in a small fraction also, Fe1.7Ti0.23O3. In hematite, Fe can be substituted by Ti, therefore we suggest that in the newfound ferberite-type phase, Ti partially substitutes for Fe leading to a small lattice distortion and a doubling of the monoclinic unit cell. In addition, Na from the substrate stabilizes the new phase: its tentative chemical formula is NaxFe0.33Ti0.67W2O8. A maximum photocurrent density of around 0.43 mA/cm2 at 1.45 V vs. RHE in 1M NaOH (pH ∼ 13.6) as an electrolyte was measured. Different aspects of the dependence of annealing and precursor solution concentration on phase transformation and photoactivity are discussed.

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