Metal oxyhydroxides represent a promising path towards a sustainable energy future but research needs to optimize synthesis and explore new nanostructures to fully realize their potential 

 

The transition from fossil fuels to renewable energy is a pressing challenge, with climate change, environmental degradation, and resource depletion driving the search for sustainable alternatives. Electrochemical energy conversion and storage (EECS) technologies hold significant promise and central to these are advanced materials that enhance their efficiency and performance. One such group of materials, metal oxyhydroxides (MOOHs), is poised to play a crucial role in the future of energy.

 

In this review article, a team of researchers including Khalifa University’s Dr. Karuppasamy Karuppasamy, under the guidance of Prof. Akram AlFantazi, reported on the advancements in MOOHs, focusing on their synthesis, structural engineering and applications in EECS. Dr. Karuppasamy collaborated with researchers from Gyeongsang National University, South Korea; Vellore Institute of Technology, India; Federal University of Mato Grosso do Sul, Brazil; The Oxford College of Science, India; Chulalongkorn University, Thailand; and Dongguk University-Seoul, Republic of Korea.

 

Their results were published in Coordination Chemistry Reviews, a top 1% journal.

 

Metal oxyhydroxides are a type of transitional metal compound that includes elements like manganese, nickel, iron, and cobalt. These materials have unique electronic structures and variable valence states, which make them particularly effective as electrocatalysts and electrode materials. Their 2D layered structures, comprising edge-sharing octahedral subunits, allow for high conductivity and improved surface texture. Various ions are also inserted into the structure to enhance the material’s overall electrochemical performance.

 

MOOHs are especially promising in supercapacitor applications. Supercapacitors are energy storage devices with high power density, long cycle life, and fast charge-discharge capabilities.

 

“MOOHs such as cobalt oxyhydroxide and nickel oxyhydroxide have shown remarkable performance as supercapacitor electrodes,” Dr. Karuppasamy says. “For instance, cobalt oxyhydroxide exhibits a high specific capacitance and stability due to its mixed valence states, which facilitate excellent reversible redox reactions.”

 

In battery technology, transition metal oxyhydroxides can serve as electrode materials in alkali metal ion batteries, providing high energy density and cycling stability. Their ability to undergo reversible redox reactions makes them ideal for next-generation battery applications, with the potential to surpass traditional materials in performance.

 

MOOHs are also effective catalysts for water electrolysis, a process which produces hydrogen fuel by splitting water into hydrogen and oxygen and is vital for the development of clean hydrogen energy. The MOOH structural properties allow for efficient electron transfer and ion diffusion, making them highly effective for both the hydrogen evolution reaction and the oxygen evolution reaction.

 

Synthesizing MOOHs involves various innovative methods, each with their own advantages. Hydrothermal and solvothermal processes allow for precise control over the nanostructures and chemical compositions, producing high-purity materials with desirable properties, while the sol-gel process produces multicomponent systems at low temperatures. Microwave-assisted synthesis is rapid and energy efficient but requires specialized equipment.

 

Despite their potential, MOOHs face several challenges. Scaling up production while maintaining quality and performance is a significant hurdle. Additionally, ensuring the long-term stability of MOOH-based materials in various electrochemical environments remains a concern.

 

MOOHs could revolutionize the field of EECS but continued research and development will be essential to fully realize their potential.

 

Jade Sterling
Science Writer
3 July 2024

New catalyst offers higher yield and reduced energy consumption to transform ammonia synthesis in the chemical industry

 

Representing a significant step towards more sustainable industrial processes, a team of researchers from Khalifa University and the Indian Institute of Technology Ropar has developed a novel catalyst designed to revolutionize the production of ammonia.

 

Ammonia is a crucial component for fertilizers and a promising carbon-free fuel. The Center of Catalysis and Separations (CeCaS) researchers published their innovative approach in ACS Energy Letters, a top 1% journal. Safa Gaber, Dr. Kayaramkodath Chandran Ranjeesh and Dr. Dinesh Shetty leveraged a covalent organic framework (COF) to efficiently couple two electrochemical reactions, achieving new highs in efficiency and yield.

 

Ammonia is a cornerstone of modern agriculture, essential for the fertilizers that support global food production. It also holds potential as a clean fuel. However, the current method of producing ammonia, the Haber-Bosch process, is highly energy-intensive and accounts for over 2% of annual global CO2 emissions. This has prompted research into greener alternatives, with electrochemical methods emerging as a promising solution.

 

While the nitrogen reduction reaction has been explored, it presents significant challenges of its own. The KU and IIT research team shifted their focus to the nitrate reduction reaction, which offers higher feasibility due to the greater solubility of nitrate ions and their lower bond dissociation energy. Plus, nitrate is a prevalent pollutant in agricultural runoff, meaning their method offers the additional benefit of pollution remediation.

 

The team developed a bifunctional catalyst that integrates ruthenium nanoclusters within a covalent organic framework. This design allows precise control over the diffusion of nitrate and protons, resulting in a highly selective and efficient conversion of nitrate to ammonia.

 

The researchers also coupled the glucose oxidation reaction at the anode of the catalyst, replacing the traditional oxygen evolution reaction. The glucose oxidation reaction requires less energy, significantly reducing the overall energy consumption of the ammonia synthesis process. It also produces valuable by-products such as gluconic and glucaric acids that can be used in other industries.

The novel catalyst achieved a 2.5 times higher ammonia yield rate compared to traditional catalysts, marking a significant step towards sustainable ammonia production. By addressing both pollution and energy efficiency, the bifunctional COF catalyst offers a practical solution for greener industrial processes.

 

Jade Sterling
Science Writer
2 July 2024

Smart cities can harness machine learning for greener grids, revolutionizing urban energy management with renewables 

 

Integrating renewable energy sources and electric vehicles (EVs) into modern cities is a necessary evolution for the urban landscape. However, the variability introduced by these green technologies poses significant challenges for traditional energy management systems.

 

A team of researchers including Khalifa University’s Prof. Ahmed Al-Durra has introduced an innovative approach that could redefine energy management in smart cities. Prof. Al-Durra collaborated with researchers from Politecnico di Milano University, Italy; Islamic Azad University, Iran; Arman Niroo Hormozgan Company, Iran; and Aalborg University, Denmark, to develop an intelligent energy management strategy for networked microgrids (NMGs) in smart cities considering renewable energy source uncertainties and power fluctuations. Their approach leverages a sophisticated combination of technologies including neural networks and deep reinforcement learning algorithms.

 

The team published their research in Sustainable Cities and Societies, a top 1% journal.

 

Smart cities are increasingly turning to NMGs as a solution to enhance energy reliability and efficiency. These microgrids can operate independently or in conjunction with the main power grid and are essential for integrating renewable energy sources and electric vehicles effectively. However, managing them in real-time, considering the unpredictable nature of solar power, for example, and EV battery usage, requires a robust, adaptable solution.

 

The research team’s solution leverages the power of machine learning to manage the active power and frequency of NMGs dynamically. Key to this strategy is its dual structure: offline training for the algorithm and decentralized operation for real-world application. This setup allows for continuous adjustment based on the operational data each microgrid collects, ensuring optimal decisions for frequency and power control.

 

The system can adapt in real-time. Offline training fine-tunes the algorithm’s responsiveness, and the decentralized operation allows for individual microgrids to make autonomous decisions based on local data.

 

The team’s system demonstrated a computation accuracy exceeding 98 percent, significantly outperforming traditional methods, with a 7.82 percent reduction in computation burden and a 61.1 percent decrease in computation time. These enhancements mean that NMGs can operate more smoothly and efficiently, with less downtime and faster responses to changes in energy demand or supply. This is particularly important in urban settings where energy demands can be unpredictable.

 

For urban planners and energy managers, this represents a step towards more sustainable urban energy practices, where green technology integration is efficient and reliable. The potential for scalability and further development opens new pathways for even smarter, more responsive urban energy grids, powered by the capabilities of machine learning.

 

Jade Sterling
Science Writer
26 June 2024

Development of copper-nickel catalysts pioneers environmentally friendly and more efficient oxygen and hydrogen production from water electrolysis 

 

 

Research at Khalifa University has led to the development of catalysts designed to improve the electrocatalytic performance of oxygen evolution reactions (OER) in water splitting. This advancement could potentially reduce the reliance on rare and expensive materials currently used in clean oxygen and hydrogen production technologies.

 

Suleiman Musa, Dr. Bilal Masood Pirzada, Shamraiz Hussain Talib, Dr. Dalaver Anjum, Dr. Mohammad Abu Haija, Dr. Sharmarke Mohamed and Dr. Ahsan Ul Haq Qurashi created copper-nickel dual atom catalysts supported on graphene. Their catalysts have demonstrated promising electrochemical properties crucial for efficiently splitting water molecules into oxygen and hydrogen during OER. The graphene base stabilizes the metallic atoms and enhances their activity by facilitating better electron mobility.

 

The team published their results in Nano Energy, a top 1% journal, with the work conducted at the Khalifa University Advanced Materials Chemistry Center.

 

Using advanced characterization techniques like X-ray diffraction and scanning electron microscopy, the team confirmed the successful dispersion of copper and nickel atoms across the graphene surface. Electrochemical tests revealed that the catalysts supported on reduced graphene oxide exhibited the lowest overpotential ­­— a measure of energy efficiency in catalysis — and the highest current density at lower voltages compared to other samples. This indicates a superior catalytic performance and the synergistic effect of the copper-nickel combination, which lowers the energy barrier for oxygen production.

 

By lowering the cost and increasing the efficiency of oxygen production, these copper-nickel graphene catalysts could revolutionize industries that rely on high-purity oxygen, such as healthcare, aerospace, and environmental engineering. Further insights provided by density functional theory calculations helped in understanding the interaction between the copper and nickel atoms and the graphene support at an atomic level. These computational models validated the experimental results and offered a theoretical explanation for the observed increase in catalytic efficiency: The unique electronic interaction between the dual atoms facilitates a more efficient catalytic process compared to single atom setups.

 

As the world continues to seek ways to reduce reliance on fossil fuels and decrease carbon emissions, the implications for sustainable energy technologies are particularly profound, given the potential for these catalysts to facilitate more environmentally friendly approaches to oxygen and hydrogen production.

 

Jade Sterling
Science Writer
24 June 2024

Analysis of zircon crystals unveils the start of Earth’s hydrological cycle

 

Four billion years ago, Earth was a vastly different place. There were no continents as we know them today, no breathable atmosphere, and life, if it existed at all, was in its most primitive forms. However, one of the fundamental processes that has shaped the evolution of life and the surface of our planet might have already been in operation.

 

Khalifa University’s Dr. Hamed Gamaleldien investigated the ancient history of the hydrological cycle to discover when and how the Earth’s water cycle began, helping to reshape our understanding of the planet’s early environment and its capacity to harbor life.

 

With researchers from Curtin University, Australia, Chinese Academy of Sciences, and China University of Petroleum, Dr. Gamaleldien focused on the oxygen isotopic signatures of zircon crystals, robust minerals that can endure geological processes without altering their primary characteristics. Found in the Jack Hills of Western Australia, these crystals can be considered geological time capsules, preserving records of environmental conditions dating back to the early stages of Earth’s formation. By examining the oxygen isotopic composition, the research team have pinpointed the onset of significant interactions between fresh water and the newly emerged continental crust.

 

The team published their results in Nature Geoscience, a top 1% journal.

 

Their results reveal two significant periods of magmatism around four billion years ago and 3.5 billion years ago, marked by very light oxygen isotopic compositions that typically came from hot, freshwater interaction with dry land. This timing is crucial, as it suggests that the hydrological cycle — crucial for creating the conditions necessary for life — began less than 600 million years after the planet’s formation.

 

“We know that minerals in rocks are chemically altered by interactions with water and this was likely happening as far back as 4.4 billion years ago,” Dr. Gamaleldien says. “We weren’t sure whether this water was saline oceanic water, meteoric (fresh), or some combination thereof, but our results show that it would be impossible for the zircon crystals to contain such light oxygen isotope signatures if the water was only salt water. There had to have been some fresh water to get these oxygen levels.”

 

The research team simulated the interactions between fresh water and the zircon crystals and demonstrated that fresh water was required to yield the very isotopically light compositions found in the Jack Hills. This provides compelling evidence for the existence of shallow magmatic-hydrothermal systems involving meteoric water at least as far back as four billion years ago.

 

“These results constrain the time period possible for the earliest presence of dry land and freshwater reservoirs, and the start of the hydrological cycle on Earth,” Dr. Gamaleldien says. “which represent the main gradients for the evolution of life.”

 

As the continents formed and stabilized, they provided platforms for the accumulation of sediments and organic materials, necessary components for the development of life.

 

The team’s results push back the timeline for the onset of the hydrological cycle and underscore the interconnectedness of geological processes and biological evolution. The presence of fresh water interacting with solid rock not only shaped the physical landscape but also created conditions perfect for the evolution of life from simple single-celled organisms to complex ecosystems. The results also challenge previous notions about the barrenness of early Earth and provide insights into the resilience and adaptability of planetary environments.

 

Understanding the timing and evolution of Earth’s hydrological cycle helps reconstruct the planet’s climatic history and can even offer clues about how life might arise on other planets, providing a broader context for the search for extraterrestrial life. 

 

Jade Sterling
Science Writer
24 June 2024

Research develops a novel control approach to mitigate delays in communication to enhance microgrid resilience

 

Microgrids, localized groups of electricity sources and loads, have become pivotal in decentralized energy systems. Their dependency on communication for distributed control introduces vulnerabilities, particularly in the form of communication delays that can destabilize the system. Prof. Ahmed Al-Durra, Dr. Khaled Ali Al-Jaafari, Prof. Hatem Zeineldin and Prof. Ehab El-Saadany, with researchers from University of Alberta, Canada, explored innovative modifications to microgrid control structures that can enhance their robustness against such delays, ensuring improved system stability without compromising control responsiveness.

 

The team published their results in Applied Energy, a top 1% journal.

 

Microgrids use distributed secondary control strategies to manage energy resources like solar panels, wind turbines and batteries efficiently. This control is crucial for maintaining system stability, frequency, and voltage within desired limits but the inherent delays in communication networks can pose significant challenges.

 

The research team proposed an enhanced control strategy that incorporates additional feedback loops into the distributed generator’s control mechanism. These modifications aim to improve the system’s ability to handle communication delays by enhancing the dynamic response of the control system. This approach differs from traditional methods that often require significant bandwidth and computational resources, focusing instead on local adjustments that reduce the system’s overall sensitivity to delays.

 

In developing their strategy, the team used a combination of mathematical modelling and simulation tests to evaluate effectiveness. By incorporating supplementary local feedback signals within each distributed generator, the modified control structure was able to maintain stability and respond to disturbances more effectively than conventional systems.

 

Simulation results demonstrated a significantly improved resilience to communication delays, with the additional feedback loops allowing a wider range of permissible control parameters and greater flexibility in system tuning. This is particularly key in environments where communication delays are unpredictable and vary widely, such as in remote or heavily networked microgrids.

 

As microgrids become more common and renewable energy sources are further incorporated, robust control mechanisms are increasingly important for more reliable and resilient power systems. The research team’s proposed control structures not only stabilize the microgrid under varying communication conditions but also ensure that the energy distribution remains efficient and stable, even in challenging operational environments.

 

Jade Sterling 
Science Writer 
14 June 2024