Group-III Nitrides Catalyzed Transformations of Organic Molecules

Abstract

New means for activating covalent bonds in organic compounds are crucial for further advancing application in fields from pharmaceuticals to plastics syntheses. The manufacturing of almost every daily product can be impacted by the development of such bond activations. However, traditional catalysts for these transformations are faced with challenges such as catalyst stability, recyclability, or energy demand. Due to their extraordinary stability, fast carrier migration rate, and accessibility through mass manufacturing of nano-level crystals, III-nitrides provide potential opportunities toward solving these challenges. Group-III nitrides, touted as the next-generation semiconductors beyond Si, have brought dramatic changes to our everyday life over the past 3 decades. With revolutionary applications in LED lighting and power electronics, the use of III-nitride semiconductors as catalysts for chemical reactions has also attracted extensive interests. However, while inorganic reactions, such as water-splitting, CO2 reduction, and N2 fixation, have made impressive achievements, the use of III-nitrides as organic reaction catalysts has received much less attention. In this review, we summarize the use of III-nitrides in the activation of covalent bonds in organic molecules to achieve more efficient or greener reactivity. With both thermal-driven and photo-driven reactions covered for a wide range of substrates, this review could inspire more innovations in the exploration of catalysis using “the semiconductors of the future,” while at the same time help bridge the boundaries of electronics and chemistry, sparking more interdisciplinary collaborations. Group-III nitrides, touted as the next-generation semiconductors beyond Si, have brought dramatic changes to our everyday life over the past 3 decades. With revolutionary applications in LED lighting and power electronics, the use of III-nitride semiconductors as catalysts for chemical reactions has also attracted extensive interests. However, while inorganic reactions, such as water-splitting, CO2 reduction, and N2 fixation, have made impressive achievements, the use of III-nitrides as organic reaction catalysts has received much less attention. In this review, we summarize the use of III-nitrides in the activation of covalent bonds in organic molecules to achieve more efficient or greener reactivity. With both thermal-driven and photo-driven reactions covered for a wide range of substrates, this review could inspire more innovations in the exploration of catalysis using “the semiconductors of the future,” while at the same time help bridge the boundaries of electronics and chemistry, sparking more interdisciplinary collaborations. While the first industrial revolution was driven by steam1Landes D.S. The Unbound Prometheus: Technical Change and Industrial Development in Western Europe from 1750 to Present. Cambridge University Press, 1969Google Scholar and the second by petroleum,2Vassiliou M.S. Historical Dictionary of the Petroleum Industry. Scarecrow Press, 2009Google Scholar the third one, the IT revolution, was inarguably backboned by the semiconductor silicon,3Heywang W. Zaininger K.H. Silicon: Evolution and Future of a Technology. Springer, 2013Google Scholar until it is now ready to be unseated by a new class of semiconductor material4Feng III, Z.C. Nitride Materials, Devices and Nano-Structures. World Scientific, 2008Google Scholar to lead the fourth great industrial revolution5Schwab K. The Fourth Industrial Revolution. Crown, 2017Google Scholar in the not so distant future. Highly anticipated as “the semiconductor of the future,”6Yoder M.N. Gallium nitride past, present, and future.in: 1997 Proceedings of the IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits. Institute of Electrical and Electronics Engineers, 1997: 3-12Crossref Google Scholar, 7Ambacher O. Growth and applications of group III-nitrides.J. Phys. D: Appl. Phys. 1998; 31: 2653-2710Crossref Scopus (1208) Google Scholar, 8Ferreyra R.A. Zhu C. Teke A. Morkoç H. Group III nitrides.in: Kasap S. Capper P. Springer Handbook of Electronic and Photonic Materials. Springer International Publishing, 2017: 743-827Crossref Scopus (3) Google Scholar III-nitrides, represented by boron nitride (BN), aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN), and their alloys, have not only made cellphones and tablets more and more portable yet powerful9Rajan S. Jena D. Gallium nitride electronics.Semicond. Sci. Technol. 2013; 28: 070301Crossref Scopus (15) Google Scholar but also enabled highly advanced technologies from military radars10Linthicum M.D. Gallium nitride-based modules set new 180-day standard for high power operation.https://www.spacewar.com/reports/Gallium_Nitride_Based_Modules_Set_New_180_Day_Standard_For_High_Power_Operation_999.htmlDate: 2011Google Scholar to space solar panels.11Lidow A. Witcher J.B. Smalley K. Enhancement mode gallium nitride (eGaN™) FET characteristics under long term stress.Government Microcircuit Applications and Critical Technology Conference. 2011; https://epc-co.com/epc/Portals/0/epc/documents/articles/eGaN_FET_Characteristics_under_Long_Term_Stress.pdfGoogle Scholar Of great interest is the enormous potential of III-nitrides in addressing the critical energy, environment, and climate issues in the 21st century,12Ristić J. Sánchez-García M.A. Calleja E. Sanchez-Páramo J. Calleja J.M. Jahn U. Ploog K.H. Algan nanocolumns grown by molecular beam epitaxy: optical and structural characterization.Phys. Stat. Sol. A. 2002; 192: 60-66Crossref Scopus (64) Google Scholar, 13Stoica T. Calarco R. Doping of III-nitride nanowires grown by molecular beam epitaxy.IEEE J. Select. Topics Quantum Electron. 2011; 17: 859-868Crossref Scopus (39) Google Scholar, 14Geelhaar L. Chèze C. Jenichen B. Brandt O. Pfüller C. Münch S. Rothemund R. Reitzenstein S. Forchel A. Kehagias T. et al.Properties of GaN nanowires grown by molecular beam epitaxy.IEEE J. Select. Topics Quantum Electron. 2011; 17: 878-888Crossref Scopus (94) Google Scholar, 15Bertness K.A. Sanford N.A. Davydov A.V. GaN nanowires grown by molecular beam epitaxy.IEEE J. Select. Topics Quantum Electron. 2011; 17: 847-858Crossref Scopus (98) Google Scholar, 16Mata R. Hestroffer K. Budagosky J. Cros A. Bougerol C. Renevier H. Daudin B. Nucleation of GaN nanowires grown by plasma-assisted molecular beam epitaxy: the effect of temperature.J. Cryst. Growth. 2011; 334: 177-180Crossref Scopus (42) Google Scholar, 17Hersee S.D. Fairchild M. Rishinaramangalam A.K. Ferdous M.S. Zhang L. Varangis P.M. Swartzentruber B.S. Talin A.A. GaN nanowire light emitting diodes based on templated and scalable nanowire growth process.Electron. Lett. 2009; 45: 75-76Crossref Scopus (76) Google Scholar, 18Knelangen M. Consonni V. Trampert A. Riechert H. In situanalysis of strain relaxation during catalyst-free nucleation and growth of GaN nanowires.Nanotechnology. 2010; 21: 245705Crossref PubMed Scopus (35) Google Scholar, 19Schumann T. Gotschke T. Limbach F. Stoica T. Calarco R. Selective-area catalyst-free mbe growth of GaN nanowires using a patterned oxide layer.Nanotechnology. 2011; 22: 095603Crossref PubMed Scopus (73) Google Scholar, 20Hersee S.D. Sun X. Wang X. The controlled growth of GaN nanowires.Nano Lett. 2006; 6: 1808-1811Crossref PubMed Scopus (484) Google Scholar, 21Liu C. Shields P.A. Chen Q. Allsopp D.W.E. Wang W.N. Bowen C.R. Phan T.-L. Cherns D. Variations in mechanisms of selective area growth of GaN on nano-patterned substrates by Movpe.Phys. Status Solidi C. 2010; 7: 32-35Crossref Scopus (18) Google Scholar, 22Choi K. Arita M. Arakawa Y. Selective-area growth of thin GaN nanowires by mocvd.J. Cryst. Growth. 2012; 357: 58-61Crossref Scopus (81) Google Scholar offering a huge market value of over $100 billion.17Hersee S.D. Fairchild M. Rishinaramangalam A.K. Ferdous M.S. Zhang L. Varangis P.M. Swartzentruber B.S. Talin A.A. GaN nanowire light emitting diodes based on templated and scalable nanowire growth process.Electron. Lett. 2009; 45: 75-76Crossref Scopus (76) Google Scholar,23Zhao S. Woo S.Y. Bugnet M. Liu X. Kang J. Botton G.A. Mi Z. Three-dimensional quantum confinement of charge carriers in self-organized Algan nanowires: A viable route to electrically injected deep ultraviolet lasers.Nano Lett. 2015; 15: 7801-7807Crossref PubMed Scopus (45) Google Scholar,24Janjua B. Sun H. Zhao C. Anjum D.H. Priante D. Alhamoud A.A. Wu F. Li X. Albadri A.M. Alyamani A.Y. et al.Droop-free AlxGa1-xN/AlyGa1-yN quantum-disks-in-nanowires ultraviolet LED emitting at 337 nm on metal/silicon substrates.Opt. Express. 2017; 25: 1381-1390Crossref PubMed Scopus (49) Google Scholar Moreover, the introduction of III-nitrides in chemistry has also sparked unprecedented reactivities.25Bozack M.J. Muehlhoff L. Russell J.N. Choyke W.J. Yates Jr., J.T. Methods in semiconductor surface chemistry.J. Vac. Sci. Technol. A. 1987; 5: 1Crossref Scopus (178) Google Scholar Water-splitting,26Hisatomi T. Kubota J. Domen K. Recent advances in semiconductors for photocatalytic and photoelectrochemical water splitting.Chem. Soc. Rev. 2014; 43: 7520-7535Crossref PubMed Google Scholar CO2 reduction,27Habisreutinger S.N. Schmidt-Mende L. Stolarczyk J.K. Photocatalytic reduction of CO2 on Tio2 and other semiconductors.Angew. Chem. Int. Ed. Engl. 2013; 52: 7372-7408Crossref PubMed Scopus (1608) Google Scholar and N2 fixation28Chen X. Li N. Kong Z. Ong W.-J. Zhao X. Photocatalytic fixation of nitrogen to ammonia: state-of-the-art advancements and future prospects.Mater. Horiz. 2018; 5: 9-27Crossref Google Scholar,29Liu M. Wang Y. Kong X. Tan L. Li L. Cheng S. Botton G. Guo H. Mi Z. Li C.-J. Efficient Nitrogen Fixation Catalyzed by gallium nitride nanowire using nitrogen and water.iScience. 2019; 17: 208-216Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar catalyzed by III-nitrides have been successfully explored and adequately documented.30Liu X. Chowdhury F.A. Vanka S. Chu S. Mi Z. Emerging applications of III-nitride nanocrystals.Phys. Status Solidi A. 2020; 217: 1900885Crossref Scopus (0) Google Scholar However, the development of III-nitride catalysts in organic chemistry has received much less attention.31Meierhofer F. Krieg L. Voss T. GaN meets organic: technologies and devices based on gallium-nitride/organic hybrid structures.Semicond. Sci. Technol. 2018; 33: 083001Crossref Scopus (8) Google Scholar The distinctive catalytic properties of III-nitrides can be closely related to their well-demonstrated electronic superiority as the next-generation semiconductor. Compared with silicon, oxides, and other traditional semiconductors, the three main electronic advantages of III-nitrides are—wide and tunable bandgap, great electromigration rate, and high breakdown voltage, which enable enhanced heat resistance, electrical resistance, and voltage-carrying ability, respectively, giving an overall performance-per-watt (PPW) enhancement of over 900 times compared with silicon (Figure 1).32IHI CorporationThe next generation semiconductor world - expanded via high-temperature, high-pressure technology.IHI Eng. Rev. 2015; 48: 16-19Google Scholar In chemistry, first, a wider bandgap enables substrates to overcome greater HOMO-LUMO barrier when catalyzed by III-nitrides,33Mehmood U. Malik M.I. Ul Haq Khan A. Hussein I.A. Harrabi K. Al-Ahmed A. Effect of outdoor temperature on the power-conversion efficiency of newly synthesized organic photosensitizer based dye-sensitized solar cells.Mater. Lett. 2018; 220: 222-225Crossref Scopus (1) Google Scholar,34Leclerc N. Chávez P. Ibraikulov O.A. Heiser T. Lévêque P. Impact of backbone fluorination on Π-conjugated polymers in organic photovoltaic devices: a review.Polymers. 2016; 8: 11Crossref Scopus (110) Google Scholar unlocking unprecedented reactivity. Second, a greater electromigration rate enables more efficient electron transfer between substrates and the semiconductor, speeding up the overall reaction.35Schwarz J.A. Felton L.E. Compensating effects in electromigration kinetics.Solid-State Electron. 1985; 28: 669-675Crossref Scopus (15) Google Scholar Third, the high breakdown voltage of III-nitrides is equivalent to the high stability of the III-nitride catalysts, which can be repeatedly recycled at the end of catalysis.36Fink D.G. Fowle F.F. Knowlton A.E. Beaty H.W. Standard Handbook for Electrical Engineers. McGraw-Hill, 1978Google Scholar Particularly, in addition to their near-ideal thermodynamic and kinetic attributes,37Kudo A. Miseki Y. Heterogeneous photocatalyst materials for water splitting.Chem. Soc. Rev. 2009; 38: 253-278Crossref PubMed Google Scholar which give extreme chemical stability and high absorption coefficients, III-nitrides possess tunable bandgap while straddling a broad range of reaction potentials for up to ~50% indium incorporation.38Moses P.G. Van de Walle C.G.V.d. Band bowing and band alignment in ingan alloys.Appl. Phys. Lett. 2010; 96: 021908Crossref Scopus (260) Google Scholar,39Chowdhury F.A. Mi Z. Kibria M.G. Trudeau M.L. Group III-nitride nanowire structures for photocatalytic hydrogen evolution under visible light irradiation.APL Mater. 2015; 3: 104408Crossref Scopus (28) Google Scholar It is worth noting that the energy bandgap of III-nitrides can be tailored from near-infrared to deep UV wavelengths, which covers nearly the entire solar spectrum. Meanwhile, both the conduction band and valence band of III-nitrides can be engineered to provide appropriate redox potential for various chemical reactions that require different driving forces. Intriguingly, III-nitride nanocrystals provide additional advantages, including enhanced light absorption and efficient charge carrier separation. Moreover, the recent discovery of N-terminated III-nitride nanocrystals, not only for their top c-plane but also for the nonpolar sidewalls can protect against photo-corrosion and oxidation and lead to unprecedented long-term stability.40Van de Walle C.G. Segev D. Microscopic origins of surface states on nitride Surfaces.J. Appl. Phys. 2007; 101: 081704Crossref Scopus (215) Google Scholar, 41Bandić Z.Z. Bridger P.M. Piquette E.C. McGill T.C. Minority carrier diffusion length and lifetime in GaN.Appl. Phys. Lett. 1998; 72: 3166-3168Crossref Scopus (114) Google Scholar, 42Jain S.C. Willander M. Narayan J. Overstraeten R.V. III–nitrides: growth, characterization, and properties.J. Appl. Phys. 2000; 87: 965-1006Crossref Scopus (1110) Google Scholar, 43Monemar B. Pozina G. Group III-nitride based hetero and quantum structures.Prog. Quantum Electron. 2000; 24: 239-290Crossref Scopus (95) Google Scholar, 44Yam F.K. Hassan Z. Ingan: an overview of the growth kinetics, physical properties and emission mechanisms.Superlattices Microstruct. 2008; 43: 1-23Crossref Scopus (178) Google Scholar, 45Kibria M.G. Qiao R. Yang W. Boukahil I. Kong X. Chowdhury F.A. Trudeau M.L. Ji W. Guo H. Himpsel F.J. et al.Atomic-scale origin of long-term stability and high performance of P-GaN nanowire arrays for photocatalytic overall pure water splitting.Adv. Mater. 2016; 28: 8388-8397Crossref PubMed Scopus (66) Google Scholar, 46Vanka S. Sun K. Zeng G. Pham T.A. Toma F.M. Ogitsu T. Mi Z. Long-term stability studies of a semiconductor photoelectrode in three-electrode configuration.J. Mater. Chem. A. 2019; 7: 27612-27619Crossref Google Scholar It is particularly worth noting that 1-D nanostructured GaN is in great favor of exposing high-density catalytic site. Nearly perfect single-crystal wurtzite GaN nanowires, grown by molecular beam epitaxy, is in great favor of the electron migration. The defects- and dislocations-free structure, together with the apparent ionicity enable that the surface states could be mainly located near the band edges, further protecting III-nitrides from being non-radiative recombination sites. In a series of our previous works, the N-terminated surface of III-nitrides could function as an efficient protection layer, enabling long-term stability45Kibria M.G. Qiao R. Yang W. Boukahil I. Kong X. Chowdhury F.A. Trudeau M.L. Ji W. Guo H. Himpsel F.J. et al.Atomic-scale origin of long-term stability and high performance of P-GaN nanowire arrays for photocatalytic overall pure water splitting.Adv. Mater. 2016; 28: 8388-8397Crossref PubMed Scopus (66) Google Scholar while being highly reactive for spontaneous dissociation of polar bonds.47Shen X. Small Y.A. Wang J. Allen P.B. Fernandez-Serra M.V. Hybertsen M.S. Muckerman J.T. Photocatalytic water oxidation at the GaN (101̅0)−water interface.J. Phys. Chem. C. 2010; 114: 13695-13704Crossref Scopus (73) Google Scholar,48Chen P.-T. Sun C.-L. Hayashi M. First-principles calculations of hydrogen generation due to water splitting on polar GaN surfaces.J. Phys. Chem. C. 2010; 114: 18228-18232Crossref Scopus (35) Google Scholar Meanwhile, III-nitrides possess a low energy barrier for proton diffusion.49Yang J. Wang D. Han H. Li C. Roles of cocatalysts in photocatalysis and photoelectrocatalysis.Acc. Chem. Res. 2013; 46: 1900-1909Crossref PubMed Scopus (1601) Google Scholar,50Shen X. Allen P.B. Hybertsen M.S. Muckerman J.T. Water adsorption on the GaN (101̅0) nonpolar surface.J. Phys. Chem. C. 2009; 113: 3365-3368Crossref Scopus (45) Google Scholar III-nitrides can form surfaces with significantly different properties. For example, both polar (zigzag) surface and nonpolar (armchair) surface can be located in BN, while GaN also possesses a polar (c-plane) surface and a nonpolar (m-plane) surface (Figure 2).51Golberg D. Bando Y. Huang Y. Terao T. Mitome M. Tang C. Zhi C. Boron nitride nanotubes and nanosheets.ACS Nano. 2010; 4: 2979-2993Crossref PubMed Scopus (1531) Google Scholar In order to take advantage of those diverse properties, in industry, III-nitrides are generally grown by the epitaxial technologies of metal-organic chemical vapor deposition (MOCVD), and molecular beam epitaxy (MBE) in large scale. In principle, the effective strain relaxation enables the dislocation- and defect-free growth of III-nitrides on foreign substrates.12Ristić J. Sánchez-García M.A. Calleja E. Sanchez-Páramo J. Calleja J.M. Jahn U. Ploog K.H. Algan nanocolumns grown by molecular beam epitaxy: optical and structural characterization.Phys. Stat. Sol. A. 2002; 192: 60-66Crossref Scopus (64) Google Scholar,23Zhao S. Woo S.Y. Bugnet M. Liu X. Kang J. Botton G.A. Mi Z. Three-dimensional quantum confinement of charge carriers in self-organized Algan nanowires: A viable route to electrically injected deep ultraviolet lasers.Nano Lett. 2015; 15: 7801-7807Crossref PubMed Scopus (45) Google Scholar,24Janjua B. Sun H. Zhao C. Anjum D.H. Priante D. Alhamoud A.A. Wu F. Li X. Albadri A.M. Alyamani A.Y. et al.Droop-free AlxGa1-xN/AlyGa1-yN quantum-disks-in-nanowires ultraviolet LED emitting at 337 nm on metal/silicon substrates.Opt. Express. 2017; 25: 1381-1390Crossref PubMed Scopus (49) Google Scholar,52Young S.P. Hwang B.R. Lee J.C. Hyunsik I. Cho H.Y. Kang T.W. Na J.H. Park C.M. Self-assembled Al(x) Ga (1-x) N nanorods grown on Si(001) substrates by using plasma-assisted molecular beam epitaxy.Nanotechnology. 2006; 17: 4640-4643Crossref PubMed Scopus (21) Google Scholar, 53Bertness K.A. Roshko A. Sanford N.A. Barker J.M. Davydov A.V. Spontaneously grown GaN and Algan nanowires.J. Cryst. Growth. 2006; 287: 522-527Crossref Scopus (143) Google Scholar, 54Zhao S. Connie A.T. Dastjerdi M.H.T. Kong X.H. Wang Q. Djavid M. Sadaf S. Liu X.D. Shih I. Guo H. Mi Z. Aluminum nitride nanowire light emitting diodes: breaking the fundamental bottleneck of deep ultraviolet light sources.Sci. Rep. 2015; 5: 8332Crossref PubMed Scopus (126) Google Scholar, 55Thomas F.K. Santino D.C. Sarwar A.T.M. Patrick J.P. Robert F.K. Roberto C.M. Deep ultraviolet emitting polarization induced nanowire light emitting diodes with al X Ga 1- X N active regions.Nanotechnology. 2014; 25: 455201Crossref PubMed Scopus (44) Google Scholar, 56Carnevale S.D. Kent T.F. Phillips P.J. Sarwar A.T.M.G. Selcu C. Klie R.F. Myers R.C. Mixed polarity in polarization-induced P–N junction nanowire light-emitting diodes.Nano Lett. 2013; 13: 3029-3035Crossref PubMed Scopus (62) Google Scholar, 57Pierret A. Bougerol C. Murcia-Mascaros S. Cros A. Renevier H. Gayral B. Daudin B. Growth, structural and optical properties of Algan nanowires in the whole composition range.Nanotechnology. 2013; 24: 115704Crossref PubMed Scopus (53) Google Scholar, 58Pierret A. Bougerol C. Hertog M.d. Gayral B. Kociak M. Renevier H. Daudin B. Structural and optical properties of alx Ga1–Xn nanowires.Phys. Status Solidi RRL. 2013; 7: 868-873Crossref Scopus (28) Google Scholar, 59Wu Y. Wang Y. Sun K. Mi Z. Molecular beam epitaxy and characterization of Algan nanowire ultraviolet light emitting diodes on al coated Si (0 0 1) substrate.J. Cryst. Growth. 2019; 507: 65-69Crossref Scopus (10) Google Scholar The surface of III-nitrides is capable of being deliberately engineered to be cation-terminated or N-terminated by controlling the growth conditions (e.g., under nitrogen atmosphere). Meanwhile, the morphology of III-nitrides could also be tailored into one-dimensional (nanowires and nanorods) or two-dimensional (monolayer, and epilayers, etc.) morphologies, depending on the practical demands. These adjustable morphological and surface polarity properties endow III-nitrides with a tunable coordination environment, presenting a unique support for tailoring the steric and electronic properties of catalytic centers. This review discusses recent applications of III-nitride semiconductors as catalysts for the dissociation or forming of covalent bonds in and transformations of organic compounds. As those types of catalytic reactivity were, to the best of our knowledge, seldom reported for indium nitride (InN), thallium nitride (TlN), and nihonium nitride (NhN), we will focus primarily on catalytic reactions involving BN, AlN, and GaN. Oxidative dehydrogenation (ODH) of alkanes for the production of olefin is an alternative pathway to the conventional energy-consuming steam-cracking process due to the favorable thermodynamics and the prevention of coke formation.60Sattler J.J. Ruiz-Martinez J. Santillan-Jimenez E. Weckhuysen B.M. Catalytic dehydrogenation of light alkanes on metals and metal oxides.Chem. Rev. 2014; 114: 10613-10653Crossref PubMed Scopus (701) Google Scholar,61Cavani F. Ballarini N. Cericola A. Oxidative dehydrogenation of ethane and propane: how far from commercial implementation?.Catal. Today. 2007; 127: 113-131Crossref Scopus (681) Google Scholar To date, several supported metal oxide catalysts, including vanadium, tungsten, and molybdenum oxides have been developed for the ODH of light alkane.62Chen K. Bell A.T. Iglesia E. Kinetics and mechanism of oxidative dehydrogenation of propane on vanadium, molybdenum, and tungsten oxides.J. Phys. Chem. B. 2000; 104: 1292-1299Crossref Google Scholar However, the main limitation of the supported metal oxide catalyst for ODH is the low selectivity toward the desired olefin because of the over-oxidation of products.63Carrero C.A. Schloegl R. Wachs I.E. Schomaecker R. Critical literature review of the kinetics for the oxidative dehydrogenation of propane over well-defined supported vanadium oxide catalysts.ACS Catal. 2014; 4: 3357-3380Crossref Scopus (229) Google Scholar In 2016, Hermans’s group reported the excellent catalytic properties of hexagonal BN (h-BN) and BN nanotubes (BNNTs) toward the oxidative dehydrogenation of propane (ODHP).64Grant J.T. Carrero C.A. Goeltl F. Venegas J. Mueller P. Burt S.P. Specht S.E. McDermott W.P. Chieregato A. Hermans I. Selective oxidative dehydrogenation of propane to propene using boron nitride catalysts.Science. 2016; 354: 1570-1573Crossref PubMed Scopus (247) Google Scholar The performance of ODHP comparing representative catalysts to BN catalysts are shown in Figure 3. Specifically, 14% conversion of propane with the selectivity of 79% propene was achieved, while the traditionally supported vanadia catalyst V/SiO2 would provide 61% propene selectivity with a 9% propane conversion rate. The major by-products when using BN materials was ethene (12%), a valuable olefin; meanwhile when V/SiO2 was used, the main by-products were COx (33%). BNNTs exhibited significantly higher activity than h-BN due to the higher surface area. The kinetic studies showed the dependence on oxygen as a reactant and a second-order dependence on PC3H8, unlike V/SiO2, which suggested a zero-order dependence to PO2 and first-order dependence on PC3H8. Together with the DFT studies and the spectroscopic data, the radical rebound mechanism for ODH of propane to propene was proposed (Figure 4). In the reaction, one oxygen molecule bonds to the boron and nitrogen atoms at the terminated armchair edge, forming a [>B–O–O–N<] active site. Then, the hydrogen atom at the secondary carbon of propane is extracted at the active site by breaking the O–O bond, and leads to one B–OH group, one nitroxyl radical, and one secondary propyl radical. The nitroxyl radical and the secondary propyl radical would rebound rapidly to form the propyl intermediate [>N–O–CH(CH3)2]. The second hydrogen atom was abstracted from the primary carbon by the adjacent active site followed by the radical rebound, which gives the di-propoxyl intermediate. Such stabilization is believed to prevent the over-oxidation from generating free radicals. After the desorption of propene and the generation of water as a side product, the active site can be regenerated with the addition of new oxygen molecules.Figure 4Radical Rebound Mechanism of ODHP Using BN MaterialsShow full captionAtom colors: B, green; N, silver.Reprinted with permission from Hermans et al.64Grant J.T. Carrero C.A. Goeltl F. Venegas J. Mueller P. Burt S.P. Specht S.E. McDermott W.P. Chieregato A. Hermans I. Selective oxidative dehydrogenation of propane to propene using boron nitride catalysts.Science. 2016; 354: 1570-1573Crossref PubMed Scopus (247) Google Scholar Copyright 2016 American Association for the Advancement of Science.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Atom colors: B, green; N, silver. Reprinted with permission from Hermans et al.64Grant J.T. Carrero C.A. Goeltl F. Venegas J. Mueller P. Burt S.P. Specht S.E. McDermott W.P. Chieregato A. Hermans I. Selective oxidative dehydrogenation of propane to propene using boron nitride catalysts.Science. 2016; 354: 1570-1573Crossref PubMed Scopus (247) Google Scholar Copyright 2016 American Association for the Advancement of Science. Besides propene, BN also exhibited high activity for the production of C4 olefin. In 2017, Hermans and co-worker extended their research to the ODH of n-butane and isobutane.65Venegas J.M. Grant J.T. McDermott W.P. Burt S.P. Micka J. Carrero C.A. Hermans I. Selective oxidation of N-butane and isobutane catalyzed by boron nitride.ChemCatChem. 2017; 9: 2118-2127Crossref Scopus (36) Google Scholar 76.2% selectivity at 1-butene or 2-butene at 7.2% conversion rate and 75.4% selectivity at isobutene at 6.2% conversion rate was obtained from n-butane and isobutane, respectively (Figure 5). Furthermore, the side products are mainly valuable light alkene (ethene and propene) rather than COx species. For the hydrogen abstraction of C4 alkanes, the same radical rebound mechanism at the [>B–O–O–N<] active site as the previous ODHP work has proposed.64Grant J.T. Carrero C.A. Goeltl F. Venegas J. Mueller P. Burt S.P. Specht S.E. McDermott W.P. Chieregato A. Hermans I. Selective oxidative dehydrogenation of propane to propene using boron nitride catalysts.Science. 2016; 354: 1570-1573Crossref PubMed Scopus (247) Google Scholar The weakest C–H bond is first cleaved by the adsorbed oxygen molecule. However, the cleavage of the second C–H bond can occur on either secondary or primary carbon, which suggests that the second hydrogen abstraction is controlled kinetically rather than thermodynamically. As for the C–C bond cleavage, after the first hydrogen abstraction and radical rebound occur, the C–C bond between O-bound carbon atom and the neighboring methyl group breaks via hydrogen transfer, which results in a propoxyl intermediate and B–O–CH3 group (Figure 6). C–C bond is more favorable with low oxygen conditions and will kinetically compete with the ODH under high oxygen partial pressure. Under low oxygen condition, a hydrogen migration will occur from the secondary carbon atom to the propoxyl oxygen atom and form the light alkene.Figure 6Proposed Mechanism of C–C Bond Cleavage under Oxygen-Lean ConditionsShow full captionReprinted with permission from Hermans et al.65Venegas J.M. Grant J.T. McDermott W.P. Burt S.P. Micka J. Carrero C.A. Hermans I. Selective oxidation of N-butane and isobutane catalyzed by boron nitride.ChemCatChem. 2017; 9: 2118-2127Crossref Scopus (36) Google Scholar Copyright 2017 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimView Large Image Figure ViewerDownload Hi-res image Download (PPT) Reprinted with permission from Hermans et al.65Venegas J.M. Grant J.T. McDermott W.P. Burt S.P. Micka J. Carrero C.A. Hermans I. Selective oxidation of N-butane and isobutane catalyzed by boron nitride.ChemCatChem. 2017; 9: 2118-2127Crossref Scopus (36) Google Scholar Copyright 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim In the same year, Wang’s group developed novel porous carbon-doped BN (BCN) nanosheets for the ODH of ethylbenzene