TiO2-HfN Radial Nano-Heterojunction: A Hot Carrier Photoanode for Sunlight-Driven Water-Splitting

The lack of active, stable, earth-abundant, and visible-light absorbing materials to replace plasmonic noble metals is a critical obstacle for researchers in developing highly efficient and cost-effective photocatalytic systems. Herein, a core–shell nanotube catalyst was fabricated consisting of atomic layer deposited HfN shell and anodic TiO2 support layer with full-visible regime photoactivity for photoelectrochemical water splitting. The HfN active layer has two unique characteristics: (1) a large bandgap between optical and acoustic phonon modes (2) and no electronic bandgap, which allows a large population of long life-time hot carriers, which are used to enhance the photoelectrochemical performance. The photocurrent density (≈2.5 mA·cm−2 at 1 V vs. Ag/AgCl) obtained in this study under AM 1.5G 1 Sun illumination is unprecedented, as it is superior to most existing plasmonic noble metal-decorated catalysts and surprisingly indicates a photocurrent response that extends to 730 nm. The result demonstrates the far-reaching application potential of replacing active HER/HOR noble metals such as Au, Ag, Pt, Pd, etc. with low-cost plasmonic ceramics.

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One-Dimensional TiO2@GaON Core-Shell Nanowires with Controlled Shell Thickness from Atomic Layer Deposition for Stable and Efficient Photoelectrochemical Water Splitting

10.26434/chemrxiv.9199796 ◽

2019 ◽

Author(s):

Jiajia Tao ◽

Hong-Ping Ma ◽

Kaiping Yuan ◽

Yang Gu ◽

Jianwei Lian ◽

...

Keyword(s):

Atomic Layer Deposition ◽

Band Gap ◽

Water Splitting ◽

Atomic Layer ◽

Photoelectrochemical Water Splitting ◽

Core Shell ◽

Photoelectrochemical Performance ◽

Highly Efficient ◽

Layer Deposition ◽

Shell Nanowires

<div>As a promising oxygen evolution reaction semiconductor, TiO2 has been extensively investigated for solar photoelectrochemical water splitting. Here, a highly efficient and stable strategy for rationally preparing GaON cocatalysts on TiO2 by atomic layer deposition is demonstrated, which we show significantly enhances the</div><div>photoelectrochemical performance compared to TiO2-based photoanodes. For TiO2@20 nm-GaON core-shell nanowires a photocurrent density up to 1.10 mA cm-2 (1.23 V vs RHE) under AM 1.5 G irradiation (100 mW cm-2) has been achieved, which is 14 times higher than that of TiO2 NWs. Furthermore, the oxygen vacancy formation on GaON as well as the band gap matching with TiO2 not only provides more active sites for water oxidation but also enhances light absorption to promote interfacial charge separation and migration. Density functional theory studies of model systems of GaON-modified TiO2 confirm the band gap reduction, high reducibility and ability to activate water. The highly efficient and stable systems of TiO2@GaON core-shell nanowires provide a deeper understanding and universal strategy for enhancing photoelectrochemical performance of photoanodes now available. </div>

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Preparation and enhanced photoelectrochemical performance of selenite-sensitized zinc oxide core/shell composite structure

Journal of Materials Chemistry A ◽

10.1039/c4ta05973e ◽

2015 ◽

Vol 3 (8) ◽

pp. 4239-4247 ◽

Cited By ~ 24

Author(s):

Tiantian Hong ◽

Zhifeng Liu ◽

Hui Liu ◽

Junqi Liu ◽

Xueqi Zhang ◽

...

Keyword(s):

Zinc Oxide ◽

Ion Exchange ◽

Chemical Synthesis ◽

Water Splitting ◽

Low Cost ◽

Core Shell ◽

Nanorod Arrays ◽

Photoelectrochemical Performance ◽

Vertically Aligned ◽

Shell Composite

A fast, versatile and low-cost hydrothermal chemical synthesis based on ion-exchange has been used to deposit a shell of cupric selenite onto vertically aligned zinc oxide nanorod arrays with a buffer layer of zinc selenite for photoelectrochemical water splitting.

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Self-managed, computerised word finding therapy as an add-on to usual care for chronic aphasia post-stroke: An economic evaluation

Clinical Rehabilitation ◽

10.1177/0269215520975348 ◽

2020 ◽

pp. 026921552097534

Author(s):

Nicholas R Latimer ◽

Arjun Bhadhuri ◽

Abu O Alshreef ◽

Rebecca Palmer ◽

Elizabeth Cross ◽

...

Keyword(s):

Cost Effectiveness ◽

Usual Care ◽

Low Cost ◽

Controlled Trial ◽

Life Time ◽

Cost Effective ◽

Quality Adjusted Life Year ◽

Post Stroke ◽

Word Finding ◽

The Cost

Objective: To examine the cost-effectiveness of self-managed computerised word finding therapy as an add-on to usual care for people with aphasia post-stroke. Design: Cost-effectiveness modelling over a life-time period, taking a UK National Health Service (NHS) and personal social service perspective. Setting: Based on the Big CACTUS randomised controlled trial, conducted in 21 UK NHS speech and language therapy departments. Participants: Big CACTUS included 278 people with long-standing aphasia post-stroke. Interventions: Computerised word finding therapy plus usual care; usual care alone; usual care plus attention control. Main measures: Incremental cost-effectiveness ratios (ICER) were calculated, comparing the cost per quality adjusted life year (QALY) gained for each intervention. Credible intervals (CrI) for costs and QALYs, and probabilities of cost-effectiveness, were obtained using probabilistic sensitivity analysis. Subgroup and scenario analyses investigated cost-effectiveness in different subsets of the population, and the sensitivity of results to key model inputs. Results: Adding computerised word finding therapy to usual care had an ICER of £42,686 per QALY gained compared with usual care alone (incremental QALY gain: 0.02 per patient (95% CrI: −0.05 to 0.10); incremental costs: £732.73 per patient (95% CrI: £674.23 to £798.05)). ICERs for subgroups with mild or moderate word finding difficulties were £22,371 and £21,262 per QALY gained respectively. Conclusion: Computerised word finding therapy represents a low cost add-on to usual care, but QALY gains and estimates of cost-effectiveness are uncertain. Computerised therapy is more likely to be cost-effective for people with mild or moderate, as opposed to severe, word finding difficulties.

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Aerosol-Deposited BiVO4 Photoelectrodes for Hydrogen Generation

Journal of Thermal Spray Technology ◽

10.1007/s11666-020-01104-8 ◽

2020 ◽

Author(s):

Charline Wolpert ◽

Thomas Emmler ◽

Maria Villa Vidaller ◽

Andreas Elsenberg ◽

Kentaro Shinoda ◽

...

Keyword(s):

Thin Films ◽

Water Splitting ◽

Hydrogen Generation ◽

Renewable Energy Sources ◽

Cold Spraying ◽

Cost Effective ◽

Aerosol Deposition ◽

Bismuth Vanadate ◽

Oxide Semiconductor ◽

Photoelectrochemical Performance

Abstract Hydrogen generation from renewable energy sources will play a key role in the concerted endeavor to constrain climate change. One environmentally friendly route, powered by sunlight, is the photoelectrochemical water splitting cell (PEC). This technology employs electrodes coated with thin films of semiconductor materials to capture light and generate charge carriers that directly drive the water splitting reaction. Bismuth vanadate is a promising metal oxide semiconductor, as it absorbs visible light, and is abundant, non-toxic and cost-effective. The present study investigates the formation of bismuth vanadate thin films by the aerosol deposition (AD) method. Operating with layer formation at room temperature, AD offers advantages over other routes for the fabrication of photoactive thin film coatings, as no binders or sintering processes need to be applied. Furthermore, compared to traditional cold spraying, micrometer-sized particles can be used, resulting in coatings with thicknesses below 1 µm. Additionally, the lower kinetic energy of the feedstock powder particles enables the use of delicate substrates, such as FTO-coated glass, expanding the range of possible PEC device configurations. The process parameters explored in this study had considerable influence on the resulting coating microstructure, which in turn showed a significant impact on the photoelectrochemical performance.

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Thermal and plasma enhanced atomic layer deposition of ultrathin TiO2 on silicon from amide and alkoxide precursors: growth chemistry and photoelectrochemical performance.

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac360c ◽

2021 ◽

Author(s):

Shane O'Donnell ◽

Feljin Jose ◽

Kyle Shiel ◽

Matthew Snelgrove ◽

Caitlin McFeely ◽

...

Keyword(s):

Atomic Layer Deposition ◽

Photoelectron Spectroscopy ◽

Protective Coatings ◽

Low Cost ◽

Atomic Layer ◽

Photoelectrochemical Cell ◽

Photoelectrochemical Performance ◽

Tio2 Thin Films ◽

Carbon Incorporation ◽

Layer Deposition

Abstract Due to its low cost and suitable band gap, silicon has been studied as a photoanode material for some time. However, as a result of poor stability during the oxygen evolution reaction (OER), Si still remains unsuitable for any extended use. Ultra-thin titanium dioxide (TiO2) films have been used as protective coatings and are shown to enhance Si photoanode lifetime with added solar to hydrogen (STH) performance improvements through distancing the oxidation reaction away from the Si photoanode surface and improved charge transport through the anode. This study details the nucleation, growth chemistry, and performance of TiO2 thin films prepared via thermal and plasma enhanced atomic layer deposition (ALD) using both titanium isopropoxide (TTIP) and Tetrakis(dimethylamido)titanium (TDMAT) as the precursor material. The effect of post ALD treatments of plasma and air annealing was also studied. Films were investigated using photoelectrochemical cell testing to evaluate photoelectrochemical performance, and in-vacuum cycle-by-cycle x-ray photoelectron spectroscopy (XPS) was used as the primary characterisation technique to study nucleation mechanisms and film properties contributing to improvements in cell performance. TiO2 grown by plasma enhanced ALD results in cleaner films with reduced carbon incorporation. However, despite increased carbon incorporation, thermally grown films showed improved photocurrent as a result of oxygen vacancies in these films. Post deposition annealing in a H2 ambient is shown to further improve photocurrent in all cases, while annealing in atmosphere leads to uniform film chemistry and enhanced photocurrent stability in all cases.

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Enhanced Photoelectrochemical Water Splitting at Hematite Photoanodes by Effect of a NiFe-Oxide co-Catalyst

Catalysts ◽

10.3390/catal10050525 ◽

2020 ◽

Vol 10 (5) ◽

pp. 525 ◽

Cited By ~ 4

Author(s):

Carmelo Lo Vecchio ◽

Stefano Trocino ◽

Sabrina Campagna Zignani ◽

Vincenzo Baglio ◽

Alessandra Carbone ◽

...

Keyword(s):

Electron Microscopy ◽

Water Splitting ◽

Oxygen Evolution ◽

Low Cost ◽

Cost Effective ◽

Photoelectrochemical Water Splitting ◽

Solid Polymer ◽

Solar Simulator ◽

Co Catalyst ◽

Electrolyte Membrane

Tandem photoelectrochemical cells (PECs), made up of a solid electrolyte membrane between two low-cost photoelectrodes, were investigated to produce “green” hydrogen by exploiting renewable solar energy. The assembly of the PEC consisted of an anionic solid polymer electrolyte membrane (gas separator) clamped between an n-type Fe2O3 photoanode and a p-type CuO photocathode. The semiconductors were deposited on fluorine-doped tin oxide (FTO) transparent substrates and the cell was investigated with the hematite surface directly exposed to a solar simulator. Ionomer dispersions obtained from the dissolution of commercial polymers in the appropriate solvents were employed as an ionic interface with the photoelectrodes. Thus, the overall photoelectrochemical water splitting occurred in two membrane-separated compartments, i.e., the oxygen evolution reaction (OER) at the anode and the hydrogen evolution reaction (HER) at the cathode. A cost-effective NiFeOx co-catalyst was deposited on the hematite photoanode surface and investigated as a surface catalytic enhancer in order to improve the OER kinetics, this reaction being the rate-determining step of the entire process. The co-catalyst was compared with other well-known OER electrocatalysts such as La0.6Sr0.4Fe0.8CoO3 (LSFCO) perovskite and IrRuOx. The Ni-Fe oxide was the most promising co-catalyst for the oxygen evolution in the anionic environment in terms of an enhanced PEC photocurrent and efficiency. The materials were physico-chemically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

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Recent Advancements and Future Prospects in Ultrathin 2D Semiconductor-Based Photocatalysts for Water Splitting

Catalysts ◽

10.3390/catal10101111 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1111

Author(s):

Xiaoyong Yang ◽

Deobrat Singh ◽

Rajeev Ahuja

Keyword(s):

Optical Properties ◽

Water Splitting ◽

Noble Metals ◽

Degradation Kinetics ◽

Low Cost ◽

General Mechanism ◽

Advantages And Disadvantages ◽

Earth Abundant ◽

Kinetics Of ◽

O2 Production

Ultrathin two-dimensional (2D) semiconductor-mediated photocatalysts have shown their compelling potential and have arguably received tremendous attention in photocatalysis because of their superior thickness-dependent physical, chemical, mechanical and optical properties. Although numerous comprehensions about 2D semiconductor photocatalysts have been amassed up to now, low cost efficiency, degradation, kinetics of charge transfer along with recycling are still the big challenges to realize a wide application of 2D semiconductor-based photocatalysis. At present, most photocatalysts still need rare or expensive noble metals to improve the photocatalytic activity, which inhibits their commercial-scale application extremely. Thus, developing less costly, earth-abundant semiconductor-based photocatalysts with efficient conversion of sunlight energy remains the primary challenge. In this review, it begins with a brief description of the general mechanism of overall photocatalytic water splitting. Then a concise overview of different types of 2D semiconductor-mediated photocatalysts is given to figure out the advantages and disadvantages for mentioned semiconductor-based photocatalysis, including the structural property and stability, synthesize method, electrochemical property and optical properties for H2/O2 production half reaction along with overall water splitting. Finally, we conclude this review with a perspective, marked on some remaining challenges and new directions of 2D semiconductor-mediated photocatalysts.

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NiFeOx decorated Ge-hematite/perovskite for an efficient water splitting system

Nature Communications ◽

10.1038/s41467-021-24428-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Ki-Yong Yoon ◽

Juhyung Park ◽

Minsu Jung ◽

Sang-Geun Ji ◽

Hosik Lee ◽

...

Keyword(s):

Water Splitting ◽

Water Oxidation ◽

Photocurrent Density ◽

Photoelectrochemical Performance ◽

Co Doping ◽

Solar Water Splitting ◽

Oxidation Performance ◽

Oxide Substrate ◽

Splitting System ◽

Co Doped

AbstractTo boost the photoelectrochemical water oxidation performance of hematite photoanodes, high temperature annealing has been widely applied to enhance crystallinity, to improve the interface between the hematite-substrate interface, and to introduce tin-dopants from the substrate. However, when using additional dopants, the interaction between the unintentional tin and intentional dopant is poorly understood. Here, using germanium, we investigate how tin diffusion affects overall photoelectrochemical performance in germanium:tin co-doped systems. After revealing that germanium is a better dopant than tin, we develop a facile germanium-doping method which suppresses tin diffusion from the fluorine doped tin oxide substrate, significantly improving hematite performance. The NiFeOx@Ge-PH photoanode shows a photocurrent density of 4.6 mA cm−2 at 1.23 VRHE with a low turn-on voltage. After combining with a perovskite solar cell, our tandem system achieves 4.8% solar-to-hydrogen conversion efficiency (3.9 mA cm−2 in NiFeOx@Ge-PH/perovskite solar water splitting system). Our work provides important insights on a promising diagnostic tool for future co-doping system design.

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Low-Cost Drugs Still Relevant in the Present-Day Era

European Journal of Clinical Medicine ◽

10.24018/clinicmed.2021.2.6.134 ◽

2021 ◽

Vol 2 (6) ◽

pp. 10-12

Author(s):

Subhashchandra Daga

Keyword(s):

Low Cost ◽

Large Population ◽

Cost Effective ◽

Medical Costs ◽

Poverty Line ◽

Essential Medicines ◽

Medical Expenses ◽

Anti Epileptic Drug ◽

Cost Of Drugs ◽

Medicines For Children

Escalating medical costs contribute to poverty in countries with low resources. The drug costs account for 17 percent of medical expenses. Revisiting time-tested, cost-effective drugs can reduce these costs. Some of them find a place in the WHO Model List of Essential Medicines for Children. The list consists of medicines for a basic healthcare system. They are safe and cost-effective. The present paper identifies co-trimoxazole and chloramphenicol as antimicrobials, chloroquine for malaria, adrenaline, theophylline for asthma, and phenobarbital as an anti-epileptic drug that merits consideration for reviving interest in them and reduce drug treatment costs. What is already known about this subject? • The cost of drugs contributes to rising medical costs. • Medical expenses push a large population below the poverty line. What does this study add? • Rediscovering the relevance of old low-cost drugs is essential. • Revisiting the WHO Model List of Essential Medicines for Children may be useful. • Drugs such as chloramphenicol and theophylline are such examples.

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Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

Nature Communications ◽

10.1038/s41467-021-27299-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Beibei Zhang ◽

Shiqiang Yu ◽

Ying Dai ◽

Xiaojuan Huang ◽

Lingjun Chou ◽

...

Keyword(s):

Water Splitting ◽

Oxygen Evolution ◽

Low Cost ◽

Photocurrent Density ◽

Partial Substitution ◽

Hydrogen Electrode ◽

Highly Efficient ◽

Promising Strategy ◽

N Incorporation ◽

Pec Water Splitting

AbstractDeveloping low-cost and highly efficient catalysts toward the efficient oxygen evolution reaction (OER) is highly desirable for photoelectrochemical (PEC) water splitting. Herein, we demonstrated that N-incorporation could efficiently activate NiFeOx catalysts for significantly enhancing the oxygen evolution activity and stability of BiVO4 photoanodes, and the photocurrent density has been achieved up to 6.4 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode (RHE), AM 1.5 G). Systematic studies indicate that the partial substitution of O sites in NiFeOx catalysts by low electronegative N atoms enriched the electron densities in both Fe and Ni sites. The electron-enriched Ni sites conversely donated electrons to V sites of BiVO4 for restraining V5+ dissolution and improving the PEC stability, while the enhanced hole-attracting ability of Fe sites significantly promotes the oxygen-evolution activity. This work provides a promising strategy for optimizing OER catalysts to construct highly efficient and stable PEC water splitting devices.

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