Physical Science and Engineering | Physical Science & Engineering

Friday, October 22, 2021

Congratulations Professor Mario Lanza!

Associate Professor Mario Lanza has received the 2021 Wiley-VCH publisher Rising Stars award!

Share this

Associate Professor of Material Science and Engineering at the PSE Division, Mario Lanza, has been awarded the 2021 Wiley-VCH Rising Stars.

"The Rising Stars series intends to celebrate the diversity of the international scientific communities that these top-tier journals serve by collecting outstanding Research Articles on studies conceptualized and supervised by recognized early career researchers from around the world."

Professor Mario Lanza was recognized by the recent paper "Variability and Yield in h-BN-Based Memristive Circuits: The Role of Each Type of Defect” published in Advanced Materials.

Research

Professor Lanza's research focuses on the integration of two-dimensional (2D) materials in solid-state nano/micro-electronic devices and circuits, with special emphasis on memristive crossbar arrays and their use to build artificial neural networks. He puts special effort on using fabrication methods compatible with the industry, and to characterize the yield and variability of large amounts of devices in a statistical manner. He is one of the world leaders on the study of hexagonal boron nitride (h-BN), as well as many other ultra-thin dielectrics for electronic devices (SiO2, HfO2, Al2O3). He is famous for his expertise on nanoelectronic characterization of multiple materials and devices using scanning probe microscopy (SPM).

To know more about Professor Lanza’s profile, click here.

Wednesday, October 20, 2021

A radical shift to link soot formation and interstellar evolution

Unusual reaction pathways to hydrocarbon clusters could bring a paradigm shift to the understanding of soot and interstellar chemistry.

Share this

Rethinking the formation and growth of polycyclic aromatic hydrocarbons (PAHs), key contributors to harmful soot particles formed during fuel combustion and the smallest dust grains in interstellar matter, is helping KAUST researchers to develop greener and more efficient combustion processes, while also shedding light on interstellar evolution.

Several pathways are proposed to explain how these large organic molecules form. These typically involve a cascade of chemical reactions that assist in removing hydrogen atoms from aromatic compounds — organic compounds comprising one or more benzene rings — to generate reactive free radicals and fusing these radicals with small hydrocarbons to yield clusters. Yet, as well as being slow, this cascade also relies on a continuous supply of radicals.

“During combustion, soot formation can be significant in a reaction environment that is deficient in radicals,” says postdoc Hanfeng Jin. “Likewise, the temperature in the interstellar medium is too low to maintain a sufficient radical pool, and radicals produced by high-energy photons in the galaxy are rare,” he adds. This contradicts current hypotheses on PAH formation, whereby radical regeneration hinges on a sequential hydrogen removal.

Departing from convention, the team led by Aamir Farooq devised a mechanism in which PAH growth consumes few radicals. The mechanism involves so-called resonance-stabilized radicals, which can bind to compounds bearing double or triple carbon bonds and transfer their reactive radical site to the resulting intermediate. This allows successive addition reactions to occur and produces larger clusters without the need for activation.

Butadiyne is a compound that contains two triple bonds that exists in relatively high concentration in hydrocarbon flames, and also in Saturn’s moon Titan. The researchers evaluated the addition of butadiyne to the resonance-stabilized radical propargyl, a key PAH precursor that is also common in interstellar chemistry.

Computational predictions and elementary reaction experiments revealed that the propargyl radical first reacted with butadiyne to produce a seven-carbon aromatic compound and its corresponding resonance-stabilized radical fulvenallenyl. Further reaction yielded a larger eleven-carbon cluster consistent with the fusion of fulvenallenyl with butadiyne without additional activation.

“This continuous butadiyne addition and cyclization mechanism is applicable in radical-deficient environments, such as post-combustion of high-load engines and interstellar media evolution,” Jin says.

Delving further into the creation of the first aromatic ring, crucial for soot and PAH formation, the researchers also discovered that propargyl provided a seven-carbon resonance-stabilized radical called vinyl-cyclopentadienyl as the first aromatic ring when added to the unsaturated compound vinylacetylene. “Originally proposed seven-carbon radicals contributing to first-ring formation were derived from benzene and the five-carbon cyclopentadienyl radical,” Jin explains.

Theory and experiments suggested that, similar to fulvenallenyl, the newly obtained vinyl-cyclopentadienyl radical was a critical intermediate in the production of larger resonance-stabilized radicals by clustering without involving benzene; thus, it offers a third pathway in the inception of aromatic precursors to PAHs.

“Resonance-stabilized radical chain reactions involve a collection of PAH growth pathways. So, more of them will be discovered in future investigations,” Jin says. While exploring alternate pathways, the researchers are also developing more accurate kinetic models to better simulate PAH formation during combustion and interstellar phenomena.

- KAUST Discovery

Thursday, October 14, 2021

Congratulations, Professor Mohamed!

Professor Mohamed Eddaoudi has been named a Fellow of the Royal Society of Chemistry.

Share this

Distinguished Professor of Chemical Science, Chemical Engineering, and Material Science and Engineering Programs, Professor Mohamed Eddaoudi, has been named a Fellow of the Royal Society of Chemistry (FRSC).

The Royal Society of Chemistry (RSC) is the United Kingdom's professional body for chemists and the largest organization in Europe for advancing the chemical sciences. The designation Fellow of the Royal Society of Chemistry (FRSC) is given to elected Fellows who have made an outstanding contribution to the advancement of chemical sciences or the advancement of the chemical sciences as a profession.

At KAUST, Distinguished Professor Mohamed is the Director of the Advanced Membranes & Porous Materials Research Center.

Research

" Professor Eddaoudi's research activities are mainly aimed at developing new strategies for the design and synthesis of functional solid-state materials from molecular building blocks and advancing the understanding of the structure-property relationship of materials. " Read Professor Mohamed's complete profile.

Sunday, October 10, 2021

CONGRATULATIONS, Prof. Mani!

Professor Mani Sarathy has been awarded Energy and Fuels Rising Stars, by the American Chemical Society (ACS).

Share this

Associate Professor of Chemical Engineering and Mechanical Engineering at the PSE Division, and Associate Director of the Clean Combustion Research Center, Mani Sarathy, has been awarded for the inaugural 2021 Energy and Fuels Rising Stars.

Energy and Fuels have established an annual recognition for high influential researchers in early and mid-career (EMCRs). The Energy and Fuels Rising Stars intend to celebrate EMCRs "critical roles in driving knowledge discovery and technological advances in the increasingly globalized research landscape".

Research

Professor Sarathy's research interest is in developing sustainable energy technologies with decreased net environmental impact. A major thrust of research is simulating the combustion chemistry of transportation fuels. He develops fundamental chemical kinetic models that can be used to simulate fuel combustion and pollutant formation in energy systems. Engine designers then use these chemical kinetic models to achieve various performance targets using computational simulations. In addition, these models can be used to determine how the chemical structure of a fuel affects pollutant formation.

To know more about Prof. Mani, click here.

Monday, October 04, 2021

CONGRATULATIONS Prof. Jorge!

Professor Jorge Gascon has been named Doctor Honoris Causa by La Universidad de Alicante.

Share this

Professor of Chemical Engineering, PSE Division, and Director of the Kaust Catalysis Center, Jorge Gascon has been named Doctor Honoris Causa by La Universidad de Alicante (UA).

The Department of Quimica Inorganica of UA nominated Professor Jorge for his work in the design of new catalysts and catalytic processes for the valorization of CO2 and other important feedstocks.

"The University of Alicante honorary degrees are awarded in recognition of the honorees’ exceptional contributions to science, education, culture, art or the progress of society, or for their devoted service to the University itself."

Research

Professor Gascon's research interests fall at the intersection of Chemical Engineering and Materials Science, including the development and demonstration of new nano-structured materials and composites. Applications include multifunctional catalysis, with special emphasis in C1 chemistry; Fischer Tropsch Synthesis; Methanol to olefins; CO2 valorization; photo-catalysis; and membrane and adsorbent development.

Tuesday, September 28, 2021

Wireless strain sensors cracked up to be better

Incorporating regular cracks in electrodes for wireless strain sensors brings surprisingly better sensitivity.

Share this

Controlling the structure of fragmented electrodes composed of carbon nanotubes could offer improved wireless monitoring of the strain on materials in a wide range of applications.

“This opens endless possibilities for every situation where accurate wireless monitoring of structures is important,” says Gilles Lubineau, Professor of Mechanical Engineering at KAUST.

Lubineau developed the technology with postdoc Hussein Nesser, who adds: “Our sensor can directly be used to assess, in-situ and with great accuracy, the strain exerted on materials.”

Monitoring the strains imposed on materials is crucial for checking the safety of everything from buildings and bridges to ships and aircraft. Strain sensors are also important subdevices for monitoring aspects of health, sports performance and robotics. Natural, manufactured and living structures are all exposed to stresses and strains that can compromise their integrity.

Most strain sensors are composed of a material that can convert physical deformation into changes in electrical resistance or capacitance. The resulting electrical signals have traditionally been carried to the detecting devices along wires, but more recently, wireless technology is bringing the obvious advantages of remote sensing. This is especially useful for detecting the strains on materials in difficult-to-reach locations, such as inbuilt structures, vehicles or inside the body.

Existing wireless systems, however, are beset by problems of low sensitivity. KAUST researchers have tackled these problems by introducing a special pattern of cracks into fragmented electrodes in a way that greatly increases the sensitivity of the electrical responses. While the team was working on such a concept in the past for resistive sensors, this is the first time it has been applied to capacitive sensors that are more suitable for passive wireless applications.

Their sensor is essentially an electrical capacitor with carefully fragmented electrodes made of carbon nanotube-containing paper. The electrical changes caused by different levels of strain generate signals that can be captured wirelessly by electromagnetic coupling.

“Our innovation brings high gauge factor to the world of wireless strain detection,” says Lubineau. Gauge factor describes the ratio of the generated electrical signal to the level of strain.

Having demonstrated their concept in principle, the researchers now plan to embed it into readily deployable systems suitable for commercialization. They will also investigate using it to detect other physical properties of materials in addition to strain.

“Our ultimate objective is to make a new generation of wire-free, battery-free and ultralow-cost sensors,” says Nesser.

- KAUST Discovery

Tuesday, September 21, 2021

Fine-tuned hydrocarbon separation at low energy cost

Metal organic framework membranes that selectively separate hydrocarbons set the stage for more sustainable petrochemical processes.

Share this

An electrochemical approach developed at KAUST produces molecular-sieving membranes that could enable a cheap energy-efficient separation of light hydrocarbons, such as olefins and paraffins. This separation, critical for the petrochemical industry, usually relies on extremely energy-intensive processes, such as distillation.

Membrane-based strategies have emerged as promising alternatives to heat-driven separation approaches. Existing polymer-based membranes are not selective enough for hydrocarbon separation and also undergo plasticization, a structural change that alters their pores, at high pressure. On the other hand, highly porous crystalline materials, called face-centered cubic metal-organic frameworks (MOFs), exhibit modular pores with precisely tunable triangular apertures. This means they can be modified to separate light hydrocarbon mixtures. Moreover, the selected MOFs are impervious to plasticization.

Conventional MOF manufacturing methods, such as solvothermal synthesis, involve reacting organic linkers of appropriate length and bulk with a metal source to yield an extended crystalline solid with desired pore geometry. However, these methods require relatively high temperatures, high pressures and long reaction times, which are not easy to scale up.

“Our approach enables the synthesis of continuous MOF films at room temperature and ambient pressure in a short time,” says Mohamed Eddaoudi, who led the study.

The researchers chose preassembled rare-earth and zirconium hexanuclear clusters as building blocks, which reacted with linkers capable of deprotonation on demand to form tiny interconnected crystallites with exposed triangular windows.

Instead of using a base, the electrochemical approach uses external electrons to deprotonate the linkers, which makes it adaptable and easier to control by adjusting the current density and linker concentration. “The protonated linkers are first added and then deprotonated in a controlled manner for immediate consumption, affording the desired crystalline materials,” says Ph.D. student Sheng Zhou.

The resulting nanoporous membranes selectively separated propylene/propane and butane/isobutane mixtures. They also performed well under high pressure, high humidity and highly corrosive conditions similar to industrial hard streams.

The team, explained senior research scientist Osama Shekhah, chose their MOF platform for its proven chemical stability. “If we translate this MOF series into continuous membranes, it will fully meet the industrial requirements and desired robustness under practical industrial extreme conditions,” he adds. “The remaining challenge is to scale up these membranes to the requisite industrial scale.”

The team collaborated with KAUST catalysis scientists to perform simulations that suggested that the zirconium-based membranes can substantially save energy and utility costs if implemented in hybrid membrane–distillation systems producing high-purity propylene.

The team is now trying to scale up the manufacturing process to generate more compact membrane modules and assess their performance under industrial conditions.

- KAUST Discovery

Tuesday, September 07, 2021

Helping semiconductors find a cooler way to relax

Extending the lifetime of hot electrons could help make solar cells more efficient.

Share this

Bandgap engineering can improve the performance of optoelectronic devices that aim to harness the energy of “hot” electrons, research from KAUST shows.

Semiconductors have a signature property known as the bandgap that essentially is a range of forbidden electron energies. Electrons with an energy above the top of the bandgap are free to move through the material, whereas those below the bottom of the bandgap are not, and no electrons with an energy in between can exist in the material.

This simple idea defines a semiconductor’s optical properties. The energy from any absorbed light is transferred to the material’s electrons. Most of the free electrons in a semiconductor have an energy near the top of the bandgap. But the absorption of photons with an energy much larger than the bandgap creates, in turn, much higher energy electrons that are also called “hot electrons.”

Understanding the process by which these so-called hot electrons relax to an energy nearer the top of the bandgap is essential for understanding the operation of light-harvesting devices. For example, the efficiency of a solar cell is reduced if this huge excess energy is lost as heat. “However, it was extremely difficult, if not impossible, to sufficiently utilize these hot electrons in real light-conversion applications due to their very short lifetimes,” says material scientist Omar Mohammed.

Mohammed and his colleagues used interface and bandgap engineering to delay hot carriers (electrons and holes) relaxation and to significantly increase their lifetimes.

The team studied a semiconductor known as a lead halide perovskite. They designed and fabricated architectures made up of multiple quantum wells: a thin layer of semiconductor sandwiched between light-absorber layers of larger bandgap material. They compared the optical properties of structures in which the wells were all the same thickness and asymmetric structures in which the well widths varied. They used a technique called femtosecond (1 femtosecond = 10-15 seconds) transient absorption spectroscopy combined with theoretical calculations to determine the timescale of the hot electron relaxation.

They found the cooling rate had a strong dependence on the quantum well thickness in the asymmetric sample and that the relaxation of the hot carriers in the asymmetric multiple quantum wells was 12.5-fold slower compared to that of the symmetric multiple quantum wells.

“This new finding provides a unique strategy on how to significantly slow down the hot carriers cooling in semiconducting materials for their better utilization in solar cells applications,” says postdoc Partha Maity.

- KAUST Discovery

Wednesday, September 01, 2021

Sieving ions with a polymer membrane

Polymer membranes with precisely controlled, uniform and very small pore structure could bring ion-sieving capacity to many applications.

Share this

Ion-sieving polymer membranes can perform with exquisite precision by gaining unprecedented control over pore size and uniformity within the membranes, KAUST researchers have shown.

The biological nervous system works by selective transport of electrically charged particles called ions through cell membranes. If manufactured membranes were able to achieve a similar ion selectivity, it could transform many technologies, including water purification, mineral extraction and energy storage.

“Achieving precise ion separation at the sub-nanometer level by polymer membranes is very challenging” says chemical engineer Zhiping Lai.

Ions are formed when atoms or molecules lose or gain electrons, therefore gaining a positive or negative electrical charge. Those derived from single atoms, such as sodium (Na+), lithium (Li+) or chloride (Cl-) ions, are smaller than 1 nanometer (10-9 meters) across. The researchers used the known sizes of ions to conduct simulation studies, which helped identify suitable monomers that could act as the molecular units needed to link into a conjugated microporous polymer (CMP) membrane structure.

They then used a process called electropolymerization to make their polymer membranes. This process uses a cyclical electric current to control the precise structure that forms when the 1,3,5-tris(N-carbazolyl) benzene monomer molecules link together.

“It was challenging to determine the resulting pore size and level of porosity because of the asymmetric membrane structure,” says Lai, adding, “to overcome this issue we had to make hundreds of samples.”

The tiny size and nature of the pores prevented their analysis from using many common structural determination methods, but a solution was found in gas physisorption, which studies the interaction of a material with gases.

In tests using solutions containing a range of ions, the membranes proved to have a selective ion-sieving performance superior to almost all other reported membranes.

“This demonstrates that our innovative polymer membranes have great potential in many energy- and environment-related ion separation processes,” says Zongyao Zhou. Removing ions from seawater to produce drinkable water is one obvious possibility. Rechargeable batteries and other energy storage systems also depend on controlling the movement of ions.

Zhou says that the next target for the team is to explore the potential of the membranes to be used in a variety of innovative chemical sensors. Many chemicals of environmental or medical interest consist of ions. Membranes that selectively allow ions of interest to pass through the membranes could be used in a new generation of more precise and flexible sensor technology.

- KAUST Discovery

In the Applied Physics Program Faculty and students engage in interdisciplinary research at the interface between fundamental physical concepts and cutting-edge technologies. They strive to exploit basic physical phenomena at the nanoscale to design innovative solutions in several applied physics specialties, such as optics and photonics, semiconductor devices, quantum electronics and novel materials for energy applications.

Find out More

The Chemical Engineering Program offers students the opportunity to develop real-world solutions to global challenges by performing rigorous coursework studies and cutting-edge research in areas including the development of new materials and processes for gas and liquid separations, for water desalination, catalysis, sustainable energy and nanotechnology as well as the advancement of new ideas in process design and control and reactor design.

Find out More

The Chemical Science Program provides a modern, research-oriented education in Chemistry. Making use of the outstanding facilities at KAUST, the program distinguishes itself with a clear focus on current challenges related to catalysis and materials.

Find out More

In the Earth Science and Engineering Program Faculty and their students engage in interdisciplinary research to understand and model geophysical processes due to the complex and changing nature of our planet. The curriculum provides a sound graduate-level education in geophysical sciences and their applications in two distinct specializations represented by two tracks:

• Fluid Earth Systems;
• Solid Earth Systems.

Find out More

Faculty and students in the Energy Resources and Petroleum Engineering (ErPE) program at KAUST engage in interdisciplinary research to understand and model hydro-chemo-thermo-mechanical coupled processes in the subsurface, with emphasis on multiphase and reactive fluid flow (oil, gas, brine, water and steam).

Find out More

The Material Science and Engineering Program equips students with fundamental and applied knowledge of nanomaterials and devices; energy conversion materials and devices; biomaterials; and advanced characterization techniques.

Find out More

The Mechanical Engineering Program focuses on the following broad areas of research: structures and mechanics of solids, fluid dynamics, thermal sciences, combustion, energy, and control and dynamics. Courses in the program provide a solid foundation in each area, covering subjects such as mechanical behavior of engineering materials, continuum mechanics, thermodynamics, experimental and numerical combustion, control design, dynamic analysis, modeling, and simulation.

Find out More

Welcome Class of 2021/2022

​​​WATCH THE DIVISION VIDEO

Research

Research

Research

MORE INFORMATION

LOCATION

MORE INFORMATION

MORE INFORMATION

LOCATION

MORE INFORMATION

LOCATION

MORE INFORMATION

LOCATION

MORE INFORMATION

LOCATION

MORE INFORMATION

​​GRADUATE PROGRAMS

Applied Physics

Chemical Engineering

Chemical Science

Earth Science and Engineering

Energy Resources and Petroleum Engineering

Material Science and Engineering

Mechanical Engineering

​FACULTIES AND RESEARCH

Faculty Research Group Labs

Affiliated Research Centers

WATCH THE DIVISION VIDEO

GRADUATE PROGRAMS

FACULTIES AND RESEARCH