scholarly journals TiO2 as a Photocatalyst for Water Splitting—An Experimental and Theoretical Review

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1687
Author(s):  
Håkon Eidsvåg ◽  
Said Bentouba ◽  
Ponniah Vajeeston ◽  
Shivatharsiny Yohi ◽  
Dhayalan Velauthapillai

Hydrogen produced from water using photocatalysts driven by sunlight is a sustainable way to overcome the intermittency issues of solar power and provide a green alternative to fossil fuels. TiO2 has been used as a photocatalyst since the 1970s due to its low cost, earth abundance, and stability. There has been a wide range of research activities in order to enhance the use of TiO2 as a photocatalyst using dopants, modifying the surface, or depositing noble metals. However, the issues such as wide bandgap, high electron-hole recombination time, and a large overpotential for the hydrogen evolution reaction (HER) persist as a challenge. Here, we review state-of-the-art experimental and theoretical research on TiO2 based photocatalysts and identify challenges that have to be focused on to drive the field further. We conclude with a discussion of four challenges for TiO2 photocatalysts—non-standardized presentation of results, bandgap in the ultraviolet (UV) region, lack of collaboration between experimental and theoretical work, and lack of large/small scale production facilities. We also highlight the importance of combining computational modeling with experimental work to make further advances in this exciting field.

2021 ◽  
Vol 23 (1) ◽  
pp. 1-4
Author(s):  
Eva Cendon ◽  
John Butcher

This general edition of the journal provides insights and results of research employing a wide range of approaches and perspectives on widening participation and lifelong learning. Studies from across the UK and international sector utilise different methodological approaches, and as such are particularly interesting, with diverse methods and ways of analysis, including phenomenographic, narrative, and thematic analysis. Overall, the articles range from exploratory case studies and small-scale research to wider range and broad scale studies, highlighting different facets and perspectives. Furthermore, the articles in this volume cover a broad spectrum of institutions and places involved in widening participation, with an emphasis on the (higher) education sector in the UK balanced by international perspectives. The first seven empirical articles are based on research activities in a secondary school, a youth centre, in further education colleges (usually focusing on post-compulsory secondary or pre-university education), in so-called post-92 universities (new(er) universities, formerly Polytechnics and teacher training colleges), and last but not least in a research intensive Russell Group university. They reported challenges from the specific local contexts of different regions in England, from the South (Chichester) to London to the North (Carlisle), and can usefully be framed in the context of international discussions appearing later in the journal.


Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 735
Author(s):  
Ping Ding ◽  
Xin Wang

Conventional sensor structure design and related fracture mechanics analysis are based on the single J-integral parameter approach of elastic-plastic fracture mechanics (EPFM). Under low crack constraint cases, the EPFM one-parameter approach generally gives a stress overestimate, which results in a great cost waste of labor and sensor components. The J-A two-parameter approach overcomes this limitation. To enable the extensive application of the J-A approach on theoretical research and sensor engineering problem, under small scale yielding (SSY) conditions, the authors developed an estimate method to conveniently and quickly obtain the constraint (second) parameter A values directly from T-stress. Practical engineering application of sensor structure analysis and design focuses on three-dimensional (3D) structures with biaxial external loading, while the estimate method was developed based on two-dimensional (2D) plain strain condition with uniaxial loading. In the current work, the estimate method was successfully extended to a 3D structure with biaxial loading cases, which is appropriate for practical sensor design. The estimate method extension and validation process was implemented through a thin 3D single edge cracked plate (SECP) specimen. The process implementation was completed in two specified planes of 3D SECP along model thickness. A wide range of material and geometrical properties were applied for the extension and validation process, with material hardening exponent value 3, 5 and 10, and crack length ratio 0.1, 0.3 and 0.7.


2021 ◽  
Vol 2115 (1) ◽  
pp. 012026
Author(s):  
Sonam Solanki ◽  
Gunendra Mahore

Abstract In the current process of producing vermicompost on a large-scale, the main challenge is to keep the worms alive. This is achieved by maintaining temperature and moisture in their living medium. It is a difficult task to maintain these parameters throughout the process. Currently, this is achieved by building infrastructure but this method requires a large initial investment and long-run maintenance. Also, these methods are limited to small-scale production. For large-scale production, a unit is developed which utilises natural airflow with water and automation. The main aim of this unit is to provide favourable conditions to worms in large-scale production with very low investment and minimum maintenance in long term. The key innovation of this research is that the technology used in the unit should be practical and easy to adopt by small farmers. For long-term maintenance of the technology lesser number of parts are used.


2020 ◽  
Vol 230 ◽  
pp. 00006
Author(s):  
Paola Lova ◽  
Paolo Giusto ◽  
Francesco Di Stasio ◽  
Giovanni Manfredi ◽  
Giuseppe M. Paternò ◽  
...  

Thanks to versatile optoelectronic properties solution processable perovskites have attracted increasing interest as active materials in photovoltaic and light emitting devices. However, the deposition of perovskite thin films necessitates wide range solvents that are incompatible with many other solution-processable media, including polymers that are usually dissolved by the perovskite solvents. In this work, we demonstrate that hybrid perovskite thin films can be coupled with all polymer planar photonic crystals with different approaches to achieve emission intensity enhancement and reshaping using different approaches. The possibility to control and modify the emission spectrum of a solution processable perovskite via a simple spun-cast polymer structure is indeed of great interest in optoelectronic applications requiring high color purity or emission directionality. Furthermore, thanks to the ease of fabrication and scalability of solution-processed photonic crystals, this approach could enable industrial scale production of low-cost, large area, lightweight and flexible polymer-perovskite lighting devices, which may be tuned without resorting to compositional engineering.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Alok Patel ◽  
Ulrika Rova ◽  
Paul Christakopoulos ◽  
Leonidas Matsakas

Abstract Background Recent evidence points to the nutritional importance of docosahexaenoic acid (DHA) in the human diet. Thraustochytrids are heterotrophic marine oleaginous microorganisms capable of synthesizing high amounts of DHA, as well as other nutraceutical compounds such as squalene, in their cellular compartment. Squalene is a natural triterpene and an important biosynthetic precursor to all human steroids. It has a wide range of applications in the cosmetic and pharmaceutical industries, with benefits that include boosting immunity and antioxidant activity. Apart from its nutritional quality, it can also be utilized for high-grade bio-jet fuel by catalytic conversion. Results In the present study, the potential of thraustochytrid strain Aurantiochytrium sp. T66 to produce DHA and squalene was evaluated. When the strain was cultivated on organosolv-pretreated birch hydrolysate (30 g/L glucose) in flask, it resulted in 10.39 g/L of cell dry weight and 4.98 g/L of total lipids, of which 25.98% was DHA. In contrast, when the strain was grown in a bioreactor, cell dry weight, total lipid, and DHA increased to 11.24 g/L, 5.90 g/L, and 35.76%, respectively. The maximum squalene yield was 69.31 mg/gCDW (0.72 g/L) when the strain was cultivated in flask, but it increased to 88.47 mg/gCDW (1.0 g/L), when cultivation shifted to a bioreactor. Conclusions This is the first report demonstrating the utilization of low cost non-edible lignocellulosic feedstock to cultivate the marine oleaginous microorganism Aurantiochytrium sp. for the production of nutraceutical vital compounds. Owing to the simultaneous generation of DHA and squalene, the strain is suitable for industrial-scale production of nutraceuticals.


2007 ◽  
Vol 1047 ◽  
Author(s):  
Lesley Frame ◽  
Pamela B. Vandiver

AbstractGodin Tepe lies along the “High Road” leading from the Mesopotamian lowlands to the northern Iranian Plateau and beyond. This site acted as a center for the exchange of goods, transmission of ideas, and spread of technology; therefore the technology and manufacturing methods represented by the artifacts at this site provide information regarding the technology in use across the Iranian Plateau. Materials analyzed from Godin Tepe include crucibles, furnace and tuyere fragments, ore, and metal artifacts dating to the early third through late second millennium B.C.E. The production materials were concentrated in only a few locations throughout the site, and they are indicative of small scale production. SEM and microprobe analyses have allowed the determination of cooling rates and temperatures attained during smelting and casting operations in antiquity. In addition, the analysis of approximately 60 metal artifacts (out of the two-hundred plus that were excavated) have contributed greatly to understanding the variability in manufacture methods present during this time period. The results of this investigation support two significant conclusions. First, the measurement and evaluation of secondary dendrite arm spacing of cast artifacts and crucible prills provides insight to the processes and cooling methods employed by ancient craftsmen. Second, the wide range in manufacturing methods shown by the microstructures of non-utilitarian artifacts, offers strong evidence for the presence of multiple producers who copied styles and typology, but not technological methods from their contemporary craftsmen.


Author(s):  
Donald W. Davis ◽  
Roland J. Guidry

Immediately after the Exxon Valdez incident, the United States Oil Pollution Act of 1990 was passed. This Act clarified the lines of responsibility associated with future oil spills. In addition to this Federal legislation, Louisiana lawmakers in 1991 enacted the Oil Spill Prevention and Response Act. Financial awards associated with this Act support a wide-range of research activities. Since 1993, 24 projects have been funded. The scope and nature of this research includes: • Oil Spill Awareness through Geoscience Education (OSAGE); • Used Oil Recycling in Louisiana’s Coastal Communities; • Evaluation and Characterization of Sorbents; • Landsat TM and Synthetic Aperture Radar to Facilitate Coastline Delineation; • Environmental Effects and Effectiveness of In-Situ Burning in Wetlands; • Bioremediation Protocol for Small-Scale Oil Spills; • Oil Spill Risk on Louisiana’s Largest Waterway; • River Time-of-Travel Modeling; • Composting Technology for Practical and Safe Remediation of Oil-Spill Residuals; • Predictability of Oceanic and Atmospheric Conditions off the Mississippi Delta; and • Phytoremediation for Oil Spill Cleanup and Habitat Restoration in Louisiana’s Marshes. Each of these projects, and others, are the result of the marriage of industry and university researchers in the identification and solution of applied oil-spill-related problems. The alliance is a good one. Important environmental issues are addressed because the selection process ensures each research initiative has the potential of being implemented by the response community. The work and knowledge gained from these projects is a clear indication of how industry and the university community can function in a collaborative manner to solve important issues — a significant partnership that clearly shows how both can benefit and a model for others to follow.


2021 ◽  
Vol 9 ◽  
Author(s):  
Sarawut Tontapha ◽  
Pikaned Uppachai ◽  
Vittaya Amornkitbamrung

Dye-sensitized solar cells (DSSCs) have been developed as a promising photovoltaic cell type in recent decades because of their low cost, environmental friendliness, ease of fabrication, and suitability for a wide range of indoor and outdoor applications, especially under diverse shaded and low-light condition. They are typically composed of three main components: a transparent conducting oxide (TCO) substrate-based working electrode with wide-bandgap semiconductors and dye sensitizer molecules, an electrolytic mediator based on redox couple species, and a TCO-based counter electrode consisting of catalyst materials. The development of intrinsic and functional organic, inorganic, metal oxide, composite, and carbon-based materials has been intensively studied to enhance the efficiency of DSSCs. A simple and low-cost fabrication process that uses natural products is also considered essential for further large-scale production. In this article, we review the fabrication of various functional materials and their effects on DSSC performance.


2021 ◽  
Vol 9 (1) ◽  
pp. 7-16
Author(s):  
Leelananda Rajapaksha ◽  
DMC Champathi Gunathilake ◽  
SM Pathirana ◽  
TN Fernando

In Sri Lanka, 70% of 21 million population live in non-urban areas, and agriculture provides livelihood for approximately 40% of them. The agricultural marketing process in the country is a complex operation due to services and functions involved in moving a crop product from where it was produced to where it would finally be consumed. Further, with a wide range of agricultural crops being produced, post-harvest handling process create different degrees of quantitative and qualitative losses in a complex market chain, which are estimated at 20% to 40% for vegetables and 30% - 40% for fruits. Improper and non-scientific post-harvest practices and handling, gaps in integration of cold chain practices & elements with post-harvest process, and lack of knowledge & awareness on many related aspects at grass root farmer level etc. appear to contribute to losses that finally prevent due economic benefits reaching the small-scale producer. In order to increase the effectiveness of post-harvest process handling of fruit and vegetables, appropriate corrective measures targeting small scale producers as well as commercial scale producers need to be popularized and practiced. At small scale producer level, promotion of appropriate low-cost post-harvest practices and procedures, facilitating low-cost cold chain elements and user-friendly information flow mechanism on market situation would certainly help avoid some of the steps that lead to losses. Monitoring system of commercial post-harvest handling process that ensure scientific bulk handling, storage and transportation of fruit and vegetables, properly designed economic centers with well regulated environmentcontrolled storages etc. would greatly reduce loses in bulk handling, ensuring better food security in the island.


2021 ◽  
Vol 263 (2) ◽  
pp. 4418-4425
Author(s):  
Han Wu ◽  
Peng Zhou ◽  
Siyang Zhong ◽  
Xin Zhang ◽  
Kunyu Luo

Multi-copters or drones are engaged in a wide range of industrial applications for their flexibility, safety and low-cost. The noise emission is becoming an issue with the expanding applications, among which the propellers that drive the drones are the major sources of noise. In this work, the noise characteristics of small-scale propellers is experimentally investigated using the advanced rotor aerodynamics and aeroacoustics test platform in an anechoic chamber at the Hong Kong University of Science and Technology (HKUST). The study will focus on the representative off-the-shelf propellers. The rotor noise will be measured by a linear array with 20 microphones, and the aerodynamic forces will be acquired by using the high-accuracy load cells. The dependence of both the tonal and broadband noise radiation with the thrust and rotation speed at various conditions will be tested. The study will enhance our understanding of the noise features of the multi-rotor powered drones, and will provide us with a better understanding of the status of the drone noise impact on the environment.


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