24/7 Space News
Developing a superbase-comparable BaTiO3-xNy oxynitride catalyst
The strongly basic sites on BaTiO3-xNy catalysts are attributed to the presence of surface nitride ions and oxygen vacancies.
Developing a superbase-comparable BaTiO3-xNy oxynitride catalyst
by Staff Writers
Tokyo, Japan (SPX) Dec 04, 2023

Basic oxide catalysts contain oxygen ions with unpaired electrons that can be shared with other species to facilitate a chemical reaction. These catalysts are widely used in the synthesis of chemicals, pharmaceuticals, and petrochemicals. There have been efforts to improve the catalytic power of these catalysts by improving their basicity or the ability to donate electrons or accept hydrogen ions. Various strategies include doping the catalyst with highly electronegative cations such as alkali metals, substituting oxide ions with anions of different valences, like hydride (H-) or nitride (N3-) ions, or increasing the electron density in the catalyst by introducing oxygen vacancies next to oxide anions.

In a recent study, a team of researchers, led by Assistant Professor Masayoshi Miyazaki and including corresponding authors, Professor Hideo Hosono and Professor Masaaki Kitano, all from Tokyo Institute of Technology (Tokyo Tech), has now developed a hexagonal BaTiO3-xNy oxynitride catalyst with basicity comparable to that of superbases. They achieved this by substituting nitride ions and oxygen vacancies into face-sharing Ti2O9 dimer sites in BaTiO3-x. Their study, published in the Journal of the American Chemical Society on 20 November 2023, lays the groundwork for the development of highly basic catalysts.

The substitution of oxygen ions with nitride ions changes the electronic structure of the catalyst and shifts the energy level of the highest occupied molecular orbitals (HOMO) upward. HOMO represents the highest energy level at which electrons are present in a molecular orbital and the upward shift makes it more favorable for electrons to be donated to a reactant's lowest unoccupied molecular orbital (LUMO). Additionally, the introduction of oxygen vacancies adjacent to the doped nitride ions increases the electron density, further raising the HOMO energy level, resulting in a highly basic catalyst with a high tendency to donate electrons.

Due to this synergetic effect, the developed oxynitride was more basic compared to materials like BaTaO2N and LaTiO2N, which do not contain oxygen vacancies. "This improved basicity stems from the coupling of substituted nitride ions to electrons at oxygen vacancies," explains Dr. Miyazaki.

The strong basicity of the oxynitride catalyst facilitated Knoevenagel condensation reactions. In these reactions, a basic catalyst accepts a proton (hydrogen ion) from the methylene group, leading to the formation of a C-C bond between the carbonyl and methylene groups.

On reacting nitriles (containing the methylene group) with benzaldehyde (representing the carbonyl group), the researchers noted that the oxynitride catalyst BaTiO2.01N0.34 could accept protons from highly basic nitrile reactants with pKa value (the negative logarithm of the acid dissociation constant (Ka) of a compound in water; a high pKa value signifies a weak acid or a strong base) as high as 23.8 and 28.9. In this regard, the catalyst's ability to accept hydrogen ions from highly basic nitrile reactants indicates a basic strength comparable to that of superbases, which have pKa values around 26.

In addition to its highly basic nature, the oxynitride catalyst was stable, undergoing no changes in the structure or electronic state after the reaction. Moreover, the catalyst maintained its catalytic activity even after repeated use, making it suitable for practical applications.

Overall, the method presented in this study to improve the basicity paves the way for the development of highly basic catalysts for various chemical processes. "The synthesis of more highly basic catalysts will require the combination of surface anion species and vacancies," concludes Dr. Miyazaki.

Research Report:BaTiO3-xNy: Highly Basic Oxide Catalyst Exhibiting Coupling of Electrons at Oxygen Vacancies with Substituted Nitride Ions

Related Links
Tokyo Institute of Technology
Space Technology News - Applications and Research

Subscribe Free To Our Daily Newsletters

The following news reports may link to other Space Media Network websites.
Canadian firm starts arbitration over Panama mine closure
Panama City (AFP) Dec 1, 2023
Canadian firm First Quantum Minerals said Friday it had initiated arbitration proceedings "to enforce its rights" under a contract with Panama, since invalidated, to operate Central America's biggest copper mine. After weeks of crippling protests sparked by concerns over the mine's environmental impact, Panama's Supreme Court on Tuesday ruled as unconstitutional a contract allowing it to continue operating the Cobre Panama mine. In a statement, First Quantum said its subsidiary Minera Panama (MP ... read more

Sierra Space's Shooting Star Module Begins Rigorous Testing at NASA Facility

Russian Progress 86 spacecraft lifts off with supplies for ISS

NASA shuttle astronaut, scientist Mary Cleave remembered as 'trailblazer'

U.S. and Saudi Arabia explore space for peaceful purposes

NASA Tests In-Flight Capability of Artemis Moon Rocket Engine

NASA, small companies eye new cargo delivery, heat shield technologies

Firefly Aerospace completes first Miranda Engine hot fire test

First launch of Europe's Ariane 6 rocket planned for mid-2024

Farewell, Solar Conjunction 2023: Sols 4023-4024

Was There Life on Mars

NASA Orbiter snaps stunning views of Mars horizon

Perseverance's Parking Spot

China's Lunar Samples on Display in Macao to Inspire Future Explorers

China Manned Space Agency Delegation Highlights SARs' Role in Space Program

Wenchang Set to Become China's Premier Commercial Space Launch Hub by Next Year

Shanghai Sets Sights on Expanding Space Industry with Ambitious 2025 Goals

Embry-Riddle's Innovative Mission Control Lab prepares students for booming space sector

Ovzon and SSC close to sealing satellite communication contract worth $10M

A major boost for space skills and research in North East England

GalaxySpace to boost mobile broadband with new-gen satellite technology

Transforming Waste into Strength: The Graphene Revolution in Concrete Recycling

The Rise of the Virtual Mission

Unlocking the secrets of natural materials

Developing a superbase-comparable BaTiO3-xNy oxynitride catalyst

Discovery of planet too big for its sun throws off solar system formation models

Minimalist or maximalist? The life of a microbe a mile underground

Webb study reveals rocky planets can form in extreme environments

Interstellar ice may hold the key to understanding life's origins

Unwrapping Uranus and its icy moon secrets

Juice burns hard towards first-ever Earth-Moon flyby

Fall into an ice giant's atmosphere

Juno finds Jupiter's winds penetrate in cylindrical layers

Subscribe Free To Our Daily Newsletters


The content herein, unless otherwise known to be public domain, are Copyright 1995-2023 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.