Hydrothermal Grown Nanoporous Iron Based Titanate, Fe₂TiO₅ for Light Driven Water Splitting

We report the synthesis of iron based titanate (Fe₂TiO₅) thin films using a simple low cost hydrothermal technique. We show that this Fe₂TiO₅ works well as a photoanode for the photoelectrochemical splitting of water due to favorable band energetic. Further characterization of thin films including band positions with respect to water redox levels has been investigated. We conclude that Fe₂TiO₅ is a promising material comparable to hematite for constructing PEC cells

Synergistic Effect of Porosity and Gradient Doping in Efficient Solar Water Oxidation of Catalyst-Free Gradient Mo:BiVO₄

In this paper, the synergistic effect of porosity and gradient of Mo doping in BiVO₄ photoanodes for improving charge separation and solar water oxidation performance is reported. A simple solution-based, three-step fabrication route was adopted using a layer-by-layer assembling technique. A water oxidation photocurrent of ∼1.73 mA cm^–2 at 1.23 V vs reversible hydrogen electrode in neutral pH was achieved without using any sacrificial agent or electrocatalyst. The gradient Mo doping was found to enhance charge separation efficiency, which was verified through a shift in the water oxidation onset potential cathodically to ∼200 mV. In addition, these results were further confirmed by a higher open-circuit photovoltage and flat band potential investigations. This was attributed to the surface energetics played by gradient Mo doping that served as the driving force in reducing the onset potential for water oxidation. The coupled effect of enhanced light absorption and charge separation was revealed by monitoring the difference in decoupling the water oxidation efficiencies of porous and planar Mo:BiVO₄ photoanodes. This study demonstrated an improvement in the catalytic and charge separation efficiency of Mo:BiVO₄ photoanodes due to the introduction of porous structured homojunctions in a gradient manner. The simple synthesis approach adopted in the present study can be utilized and scaled up in making efficient photoanodes for competent solar water oxidation cells

Additional file 1: Table S1. of Blood-feeding, susceptibility to infection with Schmallenberg virus and phylogenetics of Culicoides (Diptera: Ceratopogonidae) from the United Kingdom

GenBank sequences used in the genetic analyses of Obsoletus complex of Culicoides. Includes references listed for GenBank sequences. (DOCX 79 kb

Perovskite–Hematite Tandem Cells for Efficient Overall Solar Driven Water Splitting

Photoelectrochemical water splitting half reactions on semiconducting photoelectrodes have received much attention but efficient overall water splitting driven by a single photoelectrode has remained elusive due to stringent electronic and thermodynamic property requirements. Utilizing a tandem configuration wherein the total photovoltage is generated by complementary optical absorption across different semiconducting electrodes is a possible pathway to unassisted overall light-induced water splitting. Because of the low photovoltages generated by conventional photovoltaic materials (e.g., Si, CIGS), such systems typically consist of triple junction design that increases the complexity due to optoelectrical trade-offs and are also not cost-effective. Here, we show that a single solution processed organic–inorganic halide perovskite (CH₃NH₃PbI₃) solar cell in tandem with a Fe₂O₃ photoanode can achieve overall unassisted water splitting with a solar-to-hydrogen conversion efficiency of 2.4%. Systematic electro-optical studies were performed to investigate the performance of tandem device. It was found that the overall efficiency was limited by the hematite’s photocurrent and onset potential. To understand these limitations, we have estimated the intrinsic solar to chemical conversion efficiency of the doped and undoped Fe₂O₃ photoanodes. The total photopotential generated by our tandem system (1.87 V) exceeds both the thermodynamic and kinetic requirements (1.6 V), resulting in overall water splitting without the assistance of an electrical bias

Improving the Efficiency of Hematite Nanorods for Photoelectrochemical Water Splitting by Doping with Manganese

Here, we report a significant improvement of the photoelectrochemical (PEC) properties of hematite (α-Fe₂O₃) to oxidize water by doping with manganese. Hematite nanorods were grown on a fluorine-treated tin oxide (FTO) substrate by a hydrothermal method in the presence on Mn. Systematic physical analyses were performed to investigate the presence of Mn in the samples. Fe₂O₃ nanorods with 5 mol % Mn treatment showed a photocurrent density of 1.6 mA cm^–2 (75% higher than that of pristine Fe₂O₃) at 1.23 V versus RHE and a plateau photocurrent density of 3.2 mA cm^–2 at 1.8 V versus RHE in a 1 M NaOH electrolyte solution (pH 13.6). We attribute the increase in the photocurrent density, and thus in the oxygen evolving capacity, to the increased donor density resulting from Mn doping of the Fe₂O₃ nanorods, as confirmed by Mott–Schottky measurement, as well as the suppression of electron–hole recombination and enhancement in hole transport, as detected by chronoamperometry measurements

Silicon Decorated with Amorphous Cobalt Molybdenum Sulfide Catalyst as an Efficient Photocathode for Solar Hydrogen Generation

The construction of viable photoelectrochemical (PEC) devices for solar-driven water splitting can be achieved by first identifying an efficient independent photoanode for water oxidation and a photocathode for hydrogen generation. These two photoelectrodes then must be assembled with a proton exchange membrane within a complete coupled system. Here we report the preparation of a Si/<i>a</i>-CoMoS_<i>x</i> hybrid photocathode which shows impressive performance (onset potential of 0.25 V <i>vs</i> RHE and photocurrent <i>j</i>_sc of 17.5 mA cm^–2 at 0 V <i>vs</i> RHE) in pH 4.25 phosphate solution and under simulated AM 1.5 solar illumination. This performance is among the best reported for Si photocathodes decorated with noble-metal-free catalysts. The electrode preparation is scalable because it relies on a photoassisted electrodeposition process employing an available p-type Si electrode and [Co(MoS₄)₂]^2– precursor. Investigation of the mechanism of the Si/<i>a</i>-CoMoS_<i>x</i> electrode revealed that under conditions of H₂ photogeneration this bimetallic sulfide catalyst is highly efficient in extracting electrons from illuminated Si and subsequently in reducing protons into H₂. The Si/<i>a</i>-CoMoS_<i>x</i> photocathode is functional over a wide range of pH values, thus making it a promising candidate for the construction of a complete solar-driven water splitting PEC device

Inferred probability that <i>Culicoides</i> with a given C_q value has a transmissible infection (derived using <b>equation (2</b>)).

<p>Solid lines are the posterior median and the dashed lines indicate the 95% credible interval for (A) <i>C. sonorensis</i> and (B) <i>C. nubeculosus</i>.</p

Estimates for vector competence and the mean and standard deviation for C_q values in <i>Culicoides</i> biting midges with transmissible and sub-transmissible infections after feeding on SBV-infected blood via a membrane.

†<p>summary statistics for the marginal posterior distributions (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057747#pone.0057747.s001" target="_blank">Figure S1</a>);</p>‡<p>the posterior distribution for <i>C. nubeculosus</i> is bimodal (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057747#pone.0057747.s001" target="_blank">Figure S1</a>) and the summary statistics must be treated with caution.</p

Differences in C_q values between the dissected body parts and saliva for <i>C. sonorensis</i> infected by intrathoracic inoculation with SBV.

†<p>coefficients in the linear mixed model for C_q values.</p

Observed C_q values for Schmallenberg virus (SBV) in <i>Culicoides</i> biting midges infected via different routes and processed ten days post infection.

<p>(A) <i>C. sonorensis</i> infected via intrathoracic inoculation, incubated for ten days after which the abdomen/thorax, head and saliva of individual insects were processed separately using sqPCR. The box-and-whisker plot shows the median (horizontal line), interquartile range (box), 1.5 times the interquartile range (whiskers) and any outliers (crosses). (B) <i>C. sonorensis</i> fed orally on SBV-infected blood via a membrane-based system and processed separately as whole insects using sqPCR (C) <i>C. nubeculosus</i> fed orally on SBV-infected blood via a membrane-based system and processed separately as whole insects using sqPCR.</p