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Catalytic conversion of n-butanol to high-value-added product is considered as a highly important route towards biomass derived fine chemicals. The present work reports the applications of non-metallic multi-walled carbon nanotube (CNT) as bifunctional catalysts for oxygen assisted n-butanol conversion reactions. Oxidative dehydrogenation (ODH) and dehydration of n-butanol on CNT yielded aldehyde and alkene compounds via redox and acid catalytic routes, respectively. CNT exhibited high activity (over 50% n-butanol conversion) and stability (over 120 h) under gentle reaction conditions (<330 °C), which are competitive to conventional metal-based catalysts. Carboxylic acid groups were identified as catalytic active sites for dehydration reactions via linking the reactivity (kinetic parameters) with the surface composition and structural information of CNT catalysts. The redox activity could be related to ketonic carbonyl groups, and interestingly the intrinsic ODH catalytic activity is also influenced by degree of graphitization for CNT materials. Image 1 [ABSTRACT FROM AUTHOR]

A new synthetic strategy was developed for the fabrication of polydopamine modified carbon nanotube catalysts via in situ polymerization and subsequent thermal treatment process. The hybrid nonmetallic catalysts exhibited superior apparent and intrinsic activity than undoped or nitrogen doped carbon nanotube materials in ethylbenzene dehydrogenation reactions. The relatively high catalytic activity could be attributed to the electron transfer from polydopamine to nanocarbon matrix. The immediate result is that the improved nucleophilicity enhanced the hydrogen abstraction activity of nanocarbon catalysts, which is recognized as the rate determining step in alkane dehydrogenation reactions. [ABSTRACT FROM AUTHOR]

Abstract The applications of nanocarbon materials have been drawing an ever-increasing attention due to their unique physical and chemical properties. The performance of nanocarbon materials is determined or significantly influenced by their surface chemical composition and structure, including edges, holes, heteroatoms and functional groups etc. As a result, the accurate characterization and interpretation of the surface chemical properties of nanocarbon is extremely important, and numerous mature techniques were developed with the rapid progress of nanotechnology and characteristic instrumentation. In this review we summarized the latest development of characterization techniques for nanocarbon materials, the principles behind the techniques and the related data analysis methods. The characterization techniques are divided into four categories, including spectroscopy (IR, Raman, XPS, UPS, XAS, NMR and EELS), surface reaction (Boehm titration, potentiometric titration, chemical titration and TPSR), electron/probe microscopy (TEM, SEM, STM and AFM) and electro-chemistry methods. The most suitable application circumstances, test conditions and chemical information derivable by each characterization method are pointed out with examples, and the advantages and shortcomings of each technique are thoroughly discussed. We express the idea that full-scale structural information of nanocarbon could only be obtained by proper and comprehensive application of multiple kinds of characterization methods. [ABSTRACT FROM AUTHOR]

Ni‐promoted electrocatalytic biomass reforming has shown promising prospect in enabling high value‐added product synthesis. Here, we developed a novel hybrid catalyst with Ni nanosheet forests anchored on carbon paper. The hybrid catalyst exhibits high efficiency in electrooxidation of HMF to FDCA coupling with H2 production in high purity. The Ni nanosheets have small crystal grain sizes with abundant edges, which is able to deliver an efficient HMF oxidation to FDCA (selectivity >99 %) at low potential of 1.36 VRHE with high stability. The post‐reaction structure analysis reveals the Ni nanosheets would transfer electrons to carbon and readily turn into NiOx and Ni(OH)x during the reaction. DFT results suggest high valence Ni species would facilitate the chemical adsorption (activation) of HMF revealing the reaction pathway. This work emphasizes the importance of the precise control of Ni activity via atomic structure engineering. [ABSTRACT FROM AUTHOR]

Ni‐promoted electrocatalytic biomass reforming has shown promising prospect in enabling high value‐added product synthesis. Here, we developed a novel hybrid catalyst with Ni nanosheet forests anchored on carbon paper. The hybrid catalyst exhibits high efficiency in electrooxidation of HMF to FDCA coupling with H2 production in high purity. The Ni nanosheets have small crystal grain sizes with abundant edges, which is able to deliver an efficient HMF oxidation to FDCA (selectivity >99 %) at low potential of 1.36 VRHE with high stability. The post‐reaction structure analysis reveals the Ni nanosheets would transfer electrons to carbon and readily turn into NiOx and Ni(OH)x during the reaction. DFT results suggest high valence Ni species would facilitate the chemical adsorption (activation) of HMF revealing the reaction pathway. This work emphasizes the importance of the precise control of Ni activity via atomic structure engineering. [ABSTRACT FROM AUTHOR]

Carbon nitride modified carbon nanotubes (CN-OCNT) was prepared through simple electrostatic-dispersion and carbonization process using melamine and oxidized CNTs (oCNTs) as precursors. The stable electrostatic interactions between melamine and oCNTs enable a homogeneous dispersion of the precursor melamine on oCNTs surface. Carbon nitride (CN x ) layers formed in-situ and dispersed evenly on oCNTs surface after thermal treatment. The modification with CN x layers increased the surface area and basicity of nanocarbon materials. And the electron rich CN x layers effectively increased the nucleophilicity, and thus promoted the C H bond activation ability of nanocarbon catalysts. CN x modified nanocarbon exhibited an obviously higher intrinsic activity than unmodified ones. [ABSTRACT FROM AUTHOR]

N vacancy modified g-C 3 N 4 nano-fragments exhibit the improvement of photocatalytic performance for H 2 evolution due to synergistic effect of N vacancy and quantum confinement effect. • N vacancy modified g-C 3 N 4 nano-fragments were successfully prepared. • Quantum confinement effect was introduced in g-C 3 N 4 nano-fragments. • g-C 3 N 4 nano-fragments presented excellent photocatalytic activity. • The conduction band position of g-C 3 N 4 nano-fragments was easily adjusted. N vacancy modified g-C 3 N 4 nano-fragments were facilely prepared through thermal treatment method. The declined size and thickness of resultant g-C 3 N 4 nano-fragments make it possess quantum confinement effect. The synergistic effect of N vacancy and quantum confinement effect endows resulting g-C 3 N 4 nano-fragments with bigger surface area, stronger light response ability and improved migration effect of photoinduced charge. Not only that, the existence of quantum confinement effect remedies the shortcoming that reduced intrinsic conduction band potential was caused by N vacancy, and the conduction band position was easily adjusted. When N vacancy modified g-C 3 N 4 nano-fragments were used to produce H 2 , the H 2 evolution rate of the best sample (nano-CN5) was 5.9 folds more than bulk g-C 3 N 4 and kept admirable stability of performance, structure and feature. Clearly, the present work develops a useful strategy for adjusting conduction band position of g-C 3 N 4 and a meaningful thought for changing band gap of other photocatalysts. [ABSTRACT FROM AUTHOR]