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Li2ZnTi3O8(LZT)-xwt.%Nb2O5 (x = 0, 1, 2, 3, 4) microwave dielectric ceramics were synthesized by the conventional solid-phase sintering method. The effect of Nb2O5 addition on crystal structure, Raman spectra, and dielectric properties were studied. X-ray diffraction results indicated that the maximum crystallinity of LZT ceramics were obtained at 1075 °C, and that Nb5+ diffused into the LZT matrix completely to form a stable solid solution. XRD refinement results demonstrated that the substitution of Nb5+ for Ti4+ caused the cell volume to increase. The microscopic morphology of LZT-xwt.%Nb2O5 (x = 0, 1, 2, 3, 4) ceramics were further investigated by scanning electron microscopy, and results indicated that Nb2O5 could promote the grain growth and sintering of LZT ceramics. Extrinsic and intrinsic dielectric losses were studied through Raman and impedance spectroscopy. The highest value of quality factor × resonant frequency (Q × f) was attributed to the increase in relative density and reduced number of oxygen vacancies ( V O • • ), as well as the decrease in damping behavior. Moreover, the dielectric constant (er) showed the same trend as cell polarization and the temperature coefficient of resonant frequency (τf) was inversely proportional to cell volume. The LZT ceramics with 3 wt% Nb2O5 addition sintered at 1075 °C for 4 h exhibited the optimal microwave properties, i.e., er = 26.52, Q × f = 66 304 GHz, and τf = - 14.2 ppm/°C.

For solvent-free catalytic oxidations, low efficiency resulted from poor mass transfer and insufficient utilization of active centers remains a tough problem. Herein, we demonstrate a novel hybrid core-shell catalyst (TS@PMO) with an amphiphilic shell and a Ti-surface-enriched mesoporous TiO2-SiO2 (TS) core to address this challenge. Such TS@PMO realizes its amphiphilicity via an ex situ formed periodic mesoporous organosilica (PMO) shell. Simultaneously, by a unique etching effect induced by organic precursor growth on [SiO4] tetrahedra in TS core, active Ti sites are facilely enriched in near-surface layer of core and extra mesoporous cavities are introduced for substrate reservation. When applied for solvent-free epoxidation of methyl oleate (MO) with H2O2, TS@PMO exhibits remarkably boosted catalytic activity (X = 90.2%) and epoxide selectivity (S = 70.2%), overwhelming the unmodified titanosilicate (X = 63.7%, S = 49.2%) and Ti-containing organosilica (X = 39.8%, S = 25.0%). Such result benefits from an evidently enhanced interphase mass transfer and sufficiently accessible active Ti sites in TS@PMO. On the one hand, amphiphilic PMO shell can efficiently collect hydrophobic substrate and H2O2, while abundant mesopores in the shell offer open-path for them to access active sites in the core; on the other hand, an increased framework Ti (IV) density and their surface-enrichment in TS core greatly improve the utilization of active Ti sites. This study effectively makes up for the deficiencies of slow mass transfer and insufficient utilization of conventional titanosilicates in biphasic reactions, which paves a new avenue to exploit other hybrid catalysts for high-efficiency solvent-free catalysis.

Oxide-supported copper-containing materials have attracted considerable research attention as promising candidates for acrolein formation. Nevertheless, the elucidation of the structure-performance relationships for these systems remains a scientific challenge. In this work, copper oxide clusters deposited on a high-surface-area silica support were synthesized via a deposition-precipitation approach and exhibited remarkable catalytic reactivity (up to 25.5% conversion and 66.8% selectivity) in the propylene-selective oxidation of acrolein at 300 °C. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy combined with X-ray absorption fine structure measurements of the catalyst before and after the reaction confirmed the transformation of the small-sized copper oxide (CuO) clusters into cuprous oxide (Cu2O) clusters. With the aid of in situ X-ray diffraction and in situ dual beam Fourier transform infrared spectroscopy (DB-FTIR), the allyl intermediate (CH2=CHCH2*) was clearly observed, along with the as-formed Cu2O species. The intermediate can react with oxygen atoms from neighboring Cu2O species to form acrolein during the catalytic process, and the small-sized Cu2O clusters play a crucial role in the generation of acrolein via the selective oxidation of propylene.

Two kinds of bi-functional transition metal doped mesoporous materials (Fe-HMS and Fe-MCM-41) are prepared using one-step hydrothermal method and then treated with hydrochloric acid ethanol solution. The N2 adsorption and HRTEM results show that both of Fe-HMS and Fe-MCM-41 possess mesoporous structure. The UV–vis results suggest that the Fe species are mainly located within the framework. The basicity of as-prepared samples was studied by temperature programmed desorption using CO2 as probe molecule (CO2-TPD). The catalytic performance of Fe-HMS and Fe-MCM-41 in CO2 cycloaddition largely depends on the amount of the accessible basic sites. The acid–base active sites, framework Fe and PDDA species cooperatively catalyze the CO2 cycloaddition for the production of cyclic carbonates under the condition without any co-catalyst. The conversion of epichlorohydrin (ECH) is 97.4% and the selectivity of chloropropene carbonate is 92.9% under optimal conditions. The approximate rate constant of cycloaddition reaction of CO2 with ECH under optimum reaction temperature is calculated. It is worth noting that the Fe-HMS material shows superior reusability than Fe-MCM-41. In addition, this work provides a facile way on the synthesis of bi-functional acid–base heterogeneous catalyst with outstanding catalytic performance for the fixation of CO2.

Owing to the importance of the carbon cycle and the universality of carbon loss in sustainable hydrogen supply systems, Pt-based catalysts were designed carefully for a reversible methylcyclohexane–toluene–hydrogen (MTH) cycle. Through adjusting the activity of the Pt species toward C–H bonds to a middle level, liquid organic hydrogen carriers (LOHCs) with higher selectivity were achieved, making the MTH cycle closer to a closed carbon cycle. Specifically, in the hydrogen generation process, we tried to enhance coking resistance as well as inhibit side-reactions such as disproportionation, de-alkylation and hydro-isomerization via Cu doping in Pt/S-1. Experimentally, the selectivities of H2-rich and H2-lean LOHCs in the MTH cycle reached 99.9% with almost coke free during these two processes. Moreover, Pt-based catalysts exhibited excellent activity and durability in catalyzing the MTH cycle. The hydrogen release rate reached 445.3 mmol gPt−1 min−1 with 92.26% methylcyclohexane (MCH) conversion and a hydrogen storage rate of 1271 mmol gPt−1 min−1 was achieved with greater than 99.9% toluene conversion. Finally, through further investigating the geometric configuration and electronic environment of the Cu and Pt species, we found that the Pt was co-located and interacted with the Cu by forming an alloy. Moreover, the unique electron structure of the Cu–Pt alloy facilitated electron transfer from the Pt to the Cu, decreasing the electron density of the Pt. As a consequence, over-dehydrogenation and hydrogenolysis in the MTH cycle were inhibited.

Na+ ions in TS-1 influence the results of liquid-phase oxidations of hydrocarbons seriously, and the avoiding of Na+ ion impurity in TS-1 synthesis is crucial for its catalytic application. In this paper, however, the solvent-free gas-phase epoxidation of propylene with H2O2 vapor (G-HPPO) was investigated over TS-1 zeolites with different Na+ ion content. Significant improvement in the performance of G-HPPO process was observed with NaOH solution hydrothermally modified TS-1 which had a Na/Ti ratio of 0.68. The performance of G-HPPO process was further enhanced when the Na/Ti ratio of hydrothermally modified TS-1 was increased to 1.0 via subsequent Na+ ion impregnation. The catalyst showed 16.9% propylene conversion, 97.5% PO selectivity and 79.3% H2O2 utility at a propylene to H2O2 ratio of around 5. On the other hand, when the Na+ ion content of the hydrothermally modified TS-1 was reduced via subsequent NH4+-exchange, the resulted catalyst exhibited a remarkably deteriorated G-HPPO process performance. By Combining the characterizations of UV–Raman, UV–vis and FT-IR with DFT calculation, it is concluded that in the NaOH solution hydrothermally modified TS-1 the Na+ ions served as counter cations of the silicon hydroxyls adjacent to “open” tetra-coordinated framework Ti sites. As a result, the local environment of the “open” Ti sites (with titanium hydroxyls) was adjusted and the Ti sites were properly activated. Whereas, in the case of excess Na+ ions were introduced into the TS-1 (for example Na/Ti ratio more than 1.0), the titanium hydroxyl of the “open” Ti sites would be occupied, to which the deteriorated G-HPPO process performance was ascribed.

In this study, an attempt was made to modify Zn/HZSM-5 aromatization catalyst by successively impregnating Sn and Pt. Among prepared catalysts, the Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst exhibited excellent catalytic performances in both activation and aromatics selectivity. Multi-techniques including XRD, nitrogen physisorption, NH3-IR, TEM, HAADF-STEM/EDX and operando dual beam Fourier transform infrared (DB-FT-IR) spectroscopy were applied to study Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst to gain insight into its active sites and collaboration of them. It is concluded that, in the Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst, the aromatization of propane was catalyzed by the cooperation between Bronsted acid sites (bridging hydroxyls)–Lewis acid sites [zinc species and metallic alloy (SnPt nano clusters)]. Sn had crucial mediation effect which remarkably improved metal dispersion and finely tuned metal–metal interactions. Furthermore, the 3000-h fixed-bed propane aromatization stability test indicated that the Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst also had very prominent anti-coking deactivation ability.

In this study, solid NMR characterizations including 29Si MAS NMR, 31P MAS NMR, 27Al MAS NMR, and 27 Al MQ MAS NMR were carried out to get insights on the difference of ammonium dihydrogen phosphate (NH4H2PO4) and trimethylphosphate ((CH3)3PO4) modified nano-sized H-ZSM-5 zeolites. Results show that (CH3)3PO4 is more suitable for the phosphorus modification of the H-ZSM-5 zeolite, because it can effectively interact with aluminum species and facilitate the formation of distorted tetra-coordinated framework Al bonded with phosphorous species. This distorted framework Al species can better maintain the acidity of original framework Al during steaming treatment at high temperatures, even up to 800 °C. Relating the NH3-TPD characterization results with the catalytic cracking performance of full range FCC gasoline over the as-prepared P/H-ZSM-5 samples, we found out that the phosphorus-stabilized distorted framework Al sites are highly acidic and active. The (CH3)3PO4-modified H-ZSM-5 zeolite exhibits bright future in the application of important commercial processes operated under severe hydrothermal conditions.

An operando dual-beam Fourier transform infrared spectrometer was developed to identify the transient Bronsted acid sites (BAS) in propene aromatization over acidic HZSM-5 and Zn-modified HZSM-5 catalysts under real reaction conditions. The eliminated signals include gas-phase molecular vibrations and heat irradiation at reaction temperatures. We directly observed that the initial activation of propene over Zn2+ of Zn-modified HZSM-5 generated a substantial number of transient BAS, which serve as active sites for the subsequent aromatization reactions. Moreover, during the propene aromatization process, the desorption of aromatic precursors over the Zn2+ of Zn/HZSM-5 is easier than that over the H+ of HZSM-5, resulting in an enhanced aromatics productivity. A density functional theory calculation certified the priority of the metallic Zn2+ sites over BAS in the competitive activation of propene molecules. The generation of transient BAS is energetically favorable.

Hexamethyleneimine (HMI) is used as the structure-directing agent (SDA) in the conventional synthesis method of MCM-49 zeolite. Cyclohexanine (CA) is less toxic and cheaper than HMI. Hence, in this paper, MCM-49 zeolite was successfully synthesized by using CA as a sole SDA with the aid of seeds. Both the seed and template CA are indispensable for the synthesis of MCM-49 zeolite. The optimum synthesis conditions were obtained. The range of the SiO2/Al2O3 ratio of the initial gel was broadened to 70. The synthesis of MCM-49 followed the liquid-phase crystallization mechanism. The MCM-49 zeolites synthesized by using CA and conventional template hexamethyleneimine (HMI) exhibit similar intrinsic properties, such as morphology, acidity, BET surface area, SiO2/Al2O3, and so on. The MCM-49(CA) exhibite good catalytic activity and product distribution in alkylation of benzene with methanol.

Highly dispersed Pt–Cu alloy nanoparticles encapsulated in silicalite-1 were prepared by one-pot method. Taking propane dehydrogenation as a probe reaction, it was found that anti-coke ability was improved by encapsulation. Through H2-TPR, CO adsorption DRIFT spectra and X-ray Photoelectron Spectroscopy experiment, enhanced anti-coke ability was ascribed to the electronic environment change of encapsulated metal. And it was further confirmed by in situ coking experiment. Owning to limited acidity, metal encapsulated by silicalite-1 molecular sieve exhibited better anti-coke ability and higher propylene selectivity than that by stronger acidic ZSM-5 molecular sieve. Moreover it was found that the combination of Cu and Pt made better catalytic performance and accelerated dehydrogenation more effectively compared with monometallic catalysts. Therefore, Pt–Cu alloy nanoparticles encapsulated in silicalite-1 molecular sieve core–shell material was a potential coke-resistant catalyst for alkane dehydrogenation reaction.

The effect of the introduced base sites in CsX with alkali oxide modification towards side-chain alkylation of toluene with methanol was systematically investigated in the present work. A series of alkali oxide modified CsX with a base properties (base strength and amount) gradient were prepared by impregnating CsX with alkali metal hydroxide. Here, CsX with different base strengths were selected as the parent zeolite, which is favorable to clarify the different types of base site in the modified CsX. The base properties of the samples were elucidated based on the CO2-TPD results as well as with characterization by XPS and FT-IR of adsorbed CO2. It was revealed that the base strength of the oxygen atoms with negative charge (Oδ−) in the zeolite framework can be strengthened by the electron donating function of the alkali oxides in the supercage of CsX. Detailed analysis of the correlation between the reaction behaviors of side-chain alkylation reaction and the base properties of the indicated catalysts was carried out. It was found that the dehydrogenation of methanol to formaldehyde step was promoted by the increasing base properties of Oδ− in the CsX framework and that was the main reason for the promotion of the whole side-chain alkylation reaction. However, it was also found that the stronger base properties of the alkali oxide modified CsX would enhance the formation of active hydrogen atoms, which aggravated the unwanted styrene conversion to ethylbenzene.

Although zinc-promoted HZSM-5 catalysts have been widely used in the aromatization of short-chain hydrocarbons, the precise role of Zn in catalysis is still unclear due to the complex reaction mechanism and the lack of in situ or operando techniques. A home-built dual beam Fourier transform infrared (DB-FTIR) spectrometer, designed to eliminate the interference of gas-phase molecular vibration and heat irradiation through collecting reference and sample spectra simultaneously, can present an unimpeded view of the dynamic surface processes involved in gas/solid heterogeneous catalysis under real reaction conditions. With the aid of the DB-FTIR spectrometer, we directly observed the reaction process of iso-butane aromatization over HZSM-5 and Zn/HZSM-5. Unlike conventional studies, the aromatization was firstly performed under sub-atmospheric pressures using a home-built fixed-bed reactor. Comprehensive characterization results demonstrate that, besides their good dehydrogenation abilities, Zn species undergo strong interactions with olefin intermediates, even at sub-atmospheric pressures, but weaker interaction (or adsorption) with final aromatic products. Density functional theory studies certify that strong interactions could inhibit the desorption of olefin intermediates, which is beneficial for secondary chain-growth reactions relating to aromatics.

An aerosol-assisted hydrothermal method has been applied to synthesizing hierarchical beta zeolites with SiO2/Al2O3 ratios ranging from 44 to 392 in NaF media. Two different morphologies, including nano-aggregates with interparticle mesopores and plate-like zeolites with intracrystalline mesopores, can be formed depending on the SiO2/Al2O3 ratios of the synthesis gels. A possible mechanism for the formation of the beta zeolites has been proposed. The obtained beta zeolites show hierarchical pores, good Al species distribution and less internal defect sites. Evaluation, by the cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB), is consistent with the acidic properties and the pore structure of beta zeolites with different ratios of SiO2/Al2O3.

Pearl powder is a well-known traditional Chinese medicine for a variety of indications from beauty care to healthcare. While used for over a thousand years, there has yet to be an in-depth understanding and review in this area. The use of pearl powder is particularly growing in the biomedical area with various benefits reported due to the active ingredients within the pearl matrix itself. In this review, we focus on the emerging biomedical applications of pearl powder, touching on applications of pearl powder in wound healing, bone repairing, treatment of skin conditions, and other health indications.

Industrial production of HCN from NH3 and CH4 not only uses precious Pt or Pt−Rh catalysts but also requires extremely high temperatures (∼1600 K). From an energetic, operational, and safety perspective, a drastic decrease in temperature is highly desirable. Here, we report ammonia reforming of methane for the production of HCN and H2 at 673 K by the combination of CH4/NH3 plasma and a supported Cu/silicalite-1 catalyst. 30% CH4 conversion has been achieved with 79% HCN selectivity. Catalyst characterization and plasma diagnostics reveal that the excellent reaction performance is attributed to metallic Cu active sites. In addition, we propose a possible reaction pathway, viz. E-R reactions with N, NH, NH2, and CH radicals produced in the plasma, for the production of HCN, based on density functional theory calculations. Importantly, the Cu/silicalite-1 catalyst costs less than 5% of the commercial Pt mesh catalyst.

Human skin is a self-healing mechanosensory system that detects various mechanical contact forces efficiently through three-dimensional innervations. Here, we propose a biomimetic artificially innervated foam by embedding three-dimensional electrodes within a new low-modulus self-healing foam material. The foam material is synthesized from a one-step self-foaming process. By tuning the concentration of conductive metal particles in the foam at near-percolation, we demonstrate that it can operate as a piezo-impedance sensor in both piezoresistive and piezocapacitive sensing modes without the need for an encapsulation layer. The sensor is sensitive to an object’s contact force directions as well as to human proximity. Moreover, the foam material self-heals autonomously with immediate function restoration despite mechanical damage. It further recovers from mechanical bifurcations with gentle heating (70 °C). We anticipate that this material will be useful as damage robust human-machine interfaces., Designing mechanosensory system that detects mechanical contact forces like human skin remains a challenge. Here, the authors present artificially innervated self-healing foams by embedding 3D electrodes for piezo-impedance sensors that can operate in both piezoresistive and piezocapacitive sensing modes to address various proximity and mechanical interactions efficiently.

In this study, a series of SnO2 modified zeolite catalysts (Snx-S-1, x is the weight percentage of Sn) were prepared with SnCl2 and a defective Silicalite-1 (S-1) zeolite via facile deposition&ndash, precipitation method. It was found that the stannic species modified all-silica zeolite catalysts were active for the intermolecular condensation of ethylenediamine (EDA) to 1, 2-Diazabicyclo [2, 2, 2] octane (TEDA) and piperazine (PIP). The best catalyst Sn6-S-1 (6 wt.% Sn loading) showed 86% EDA conversion and 93% total selectivity to TEDA and PIP. By contrast, the defective S-1 zeolite parent showed only approximately 9% EDA conversion under the same conditions. With the help of catalyst characterization techniques including hydroxyl vibration and pyridine adsorption FT-IR spectroscopy (transmission mode), the enhancement of the catalytic activity of the SnO2 modified zeolite catalysts (Snx-S-1) was mainly attributed to the formation of mild Lewis acid sites in the siliceous zeolite. Both the hydroxyl nests of the defective S-1 zeolite and the dispersed SnO2 clusters should be the important factors for the formation of mild Lewis acid sites on the modified zeolite. Based on the catalytic performance of the modified zeolite in the conversion of EDA to PIP and TEDA, it is inferred that the mildly acidified defective S-1 zeolite by the SnO2 deposition modification might become a very active and durable catalyst for reactions involving strongly alkaline reactants and products.

With different oxidants (aqueous H2O2 or cumene hydroperoxide), Ti-containing silica catalysts (hierarchical TS-1, Ti-MCM-41, and Ti-HMS) were applied as catalysts for the epoxidation of methyl oleate (MO) and vegetable-derived unsaturated fatty acid methyl esters (FAMEs). We found that the catalytic performances of titanium silicalites were highly dependent on oxidant types. For the epoxidation of MO over hierarchical TS-1 (HTS-1), aqueous H2O2 is a better oxidant compared with cumene hydroperoxide (CHP). Benefiting from good molecular accessibility and high activity of Ti sites, combined with high hydrophobicity, ultra-high-yield epoxides were obtained over HTS-1. In contrast, CHP was more favorable for Ti-HMS catalyst, which was beneficial to selective conversion of MO into epoxide under solvent-free conditions. The superior catalytic performance was ascribed to the high surface area and pore volume of Ti-HMS. Furthermore, the corresponding structure–catalytic performance relationships and reusability ...

In this study, an attempt was made to modify the Zn/HZSM-5 aromatization catalyst by successively impregnating Fe and Pt. Multitechniques including NH3 adsorption FT-IR, TEM, HAADF-STEM, XPS, and o...

Hydrocyanic acid is an important synthetic material in chemical industry. Currently, the industrial methods of producing HCN mainly include the Andrussow and BMA processes, which are necessarily operated at temperatures of more than 1000 °C. This paper proposes a method to synthesize HCN at low temperature (400 °C) through a C–N coupling reaction in CH4/NH3 nonthermal plasma with the assistance of Pt/TS-1 catalyst. Under the optimized reaction conditions (CH4/NH3 = 1:2, GHSV: 2425 s–1, discharge length: 3 cm, reaction temperature: 400 °C, Pt/TS-1 + plasma), 80.9% HCN selectivity was achieved with 25.9% CH4 conversion. During the reaction process, the nonthermal plasma played a role of activating CH4 and NH3 into radical species (CHx and NHy), while the Pt/TS-1 catalyst promoted the C–N coupling reaction of the radical species to produce HCN.

It is still a big challenge to hydrothermally synthesize Sn-Beta zeolite by using lower amount of template and mineralizing agent in a relatively short crystallization time. To solve the problems an aerosol-seed-assisted method was used to synthesize Sn-beta zeolites. The optimum synthesis conditions were explored by varying the different synthesis parameters. It was found that the dense synthesis system help to lower the required amount of the template and hazardous mineralizing agent, and shorten the crystallization time. The crystallization of the Sn-Beta zeolite follows the liquid-phase mechanism. The incorporation of the tin species into the framework created strong Lewis acid sites, which was confirmed by UV–Vis, pyridine-FT-IR and CD3CN-FT-IR techniques. The good catalytic performances of the Sn-Beta zeolite catalysts were observed in the Baeyer–Villiger oxidation of cyclohexanone with H2O2.

Mesoporous TS-1 (MTS-1) containing organic templates tetrapropylammonium hydroxide (TPAOH) and polydiallyldimethylammonium chloride is synthesized and treated with different concentrations of hydrochloric acid aqueous solution. The as-synthesized MTS-1 are characterized using X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy, transmission electron microscopy, UV–vis, 13C cross-polarization/magic angle spinning (CP/MAS) NMR, thermogravimetry analysis, CO2-temperature-programmed desorption (TPD), N2 adsorption–desorption, X-ray fluorescence, and elemental analysis. The results of 13C CP/MAS NMR show that the structures of organic templates are retained after acid washing treatment. Not required to be removed by calcination, the organic templates embedded in MTS-1 can take the role of basic sites and activate carbon dioxide (CO2), which is confirmed by FT-IR. Moreover, the amount of acid sites and basic sites in the samples before and after acid treatment is cha...

For the initial activation of short-chain alkanes over Zn/HZSM-5 catalyst, the impact of branching degree and carbon numbers of reactants on the competition between dehydrogenation and cracking was systematically studied by experiment and calculation. The experiments were carried out on fixed-bed flow micro-reactor over HZSM-5 and Zn/HZSM-5 catalysts, by using n-butane/i-butane and propane/n-hexane as reactants with different branching degree and carbon numbers. Compared with HZSM-5, Zn/HZSM-5 obviously accelerated the cracking of C–H bond of short-chain alkanes and increased the selectivity of BTX aromatics. The selectivity to hydrogen produced from n-butane and n-hexane was higher than i-butane and propane, respectively. On the contrary, the selectivity to methane was correspondingly lower, i-butane and propane with high percentage of terminal carbons effectively suppressed the dehydrogenation. The key point to decide the reaction process through dehydrogenation or cracking is the initially activated sites of reactant. To verify this conclusion, theoretical calculations were carried out. The results showed that the (Zn–O–Zn)2+ Lewis acid sites of Zn/HZSM-5 accelerated the cracking of C–H and C–C bond simultaneously. Namely, if the initial activation occurred on the terminal carbons of reactant, the subsequent reaction would be kinetically competitive between cracking and dehydrogenation. Cracking would inevitably occur (thermodynamically favorable), and then the by-products of methane and ethane were produced in large amount. If the initial activation occurred on the internal carbons, the dehydrogenation reaction is kinetically favorable, which is beneficial to reducing the dry gas production. Therefore, cracking is more favorable than dehydrogenation for smaller alkanes and branched alkanes with high percentage of terminal carbons. The percentage of terminal carbons of short-chain alkanes determines the probability of dehydrogenation route over Zn/HZSM-5. The activation of the internal carbon via the dehydrogenation route is more favorable for the normal alkane with higher carbon number during the first stage of conversion suppressing the formation of the by-products of methane and ethane.

The epoxidation of methyl oleate (MO) was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1 (HTS-1) as the catalyst; the catalyst was synthesized using polyquaternium-6 as the mesopore template. The effects of various parameters, i.e., H2O2/C=C molar ratio, oxidant concentration, amount of the catalyst, reaction temperature, and time, were systematically studied. Furthermore, response surface methodology (RSM) was used to optimize the conditions to maximize the yield of epoxy MO and to evaluate the significance and interplay of the factors affecting the epoxy MO production. The H2O2/C=C molar ratio and catalyst amount were the determining factors for MO epoxidation, wherein the maximum yield of epoxy MO reached 94.9% over HTS-1 under the optimal conditions.

In short-chain alkane aromatization catalyzed by metal-modified HZSM-5, the metal cations acting as Lewis acid sites are considered to be the active centres for the dehydrogenation. However, other possible effects of the metal cations during the reaction have been neglected. In this study, a combination of experiments and DFT calculations has been carried out to investigate the complete effects of the Zn on ZSM-5 in isobutane aromatization. Zn8.47/HZSM-5 (Zn/Al > 1) with weak acidic properties was prepared as a Lewis acid sites-dominated catalyst. It was found that the (Zn–O–Zn)2+ Lewis acid sites acted as the main active sites and no bridged hydroxyl groups (Bronsted acid sites) were present. In isobutane conversion, it was surprisingly found that Zn8.47/HZSM-5 showed better catalytic performance at low temperature than HZSM-5 (Bronsted acid sites-dominated catalyst) and Zn2.34/HZSM-5 (Bronsted and Zn-Lewis acid sites co-existing catalyst). DFT calculations and operando dual-beam Fourier transform infrared spectrometry (DB-FTIR) characterization were employed to understand how the isobutane aromatization could be catalyzed on the Lewis acid site (Zn–O–Zn)2+ exclusively without the participation of bridged hydroxyl groups. It was directly observed over DB-FTIR that the Lewis acid-type Zn/HZSM-5 enjoyed a faster aromatization rate and higher stability than HZSM-5 under real aromatization conditions. This firstly testified that the complete reaction of isobutane aromatization could be exclusively catalyzed by (Zn–O–Zn)2+ Lewis acid sites without the participation of bridged hydroxyl groups. The [Zn-(OH)−]+ species could be produced in situ and acted as the Bronsted acid sites. Owing to the weak acidity of [Zn-(OH)−]+, the Lewis acid sites played a key role during the aromatization reactions via the carbanionic mechanism.

Side-chain alkylation of toluene with methanol is a potential technology to realize the one-step production of styrene under mild conditions. Herein, a series of cesium X zeolites with different cesium contents were prepared through an ion-exchange method. The performance of the CsX zeolites was extensively investigated in the side-chain alkylation of toluene and methanol. The acid–base properties of the involved CsX were characterized and the results showed that the acid–base properties present regular changes with varied cesium contents. Based on the full understanding of the acid–base properties of the involved CsX, the reaction behaviors of the main and side reactions in the side-chain alkylation of toluene with methanol over CsX were investigated and new insights were revealed. It has been found that the crucial steps for the main reactions were the activation of toluene and the formation of formaldehyde from dehydrogenation of methanol when the cesium exchange degree of CsX was lower and higher than 32.3%, respectively. The hydride transfer reaction between styrene and carbon deposition is responsible for the formation of ethylbenzene over CsX with lower cesium contents, while the transfer hydrogenation of styrene with methanol and formaldehyde was the main path for ethylbenzene formation over CsX with higher cesium contents. And it was found that the existence of Bronsted acid sites accounts for the formation of xylene over CsX. These new findings will give a new insight into the reaction behaviors of the side-chain alkylation of toluene with methanol over CsX and may also provide a potential modification method for high-efficiency catalysts.

Hierarchical macro/meso/microporous Silicalite-1 single crystals were successfully fabricated based on an in situ dissolution–crystallization strategy without the assistance of secondary templates and the corresponding fabrication mechanism was systematically investigated in this study. Mesoporous silica sphere (MSS) precursors could provide a quasi “space-occupying” effect to construct intracrystalline macropores while functioning as silica sources. Various factors including the amount of tetrapropylammonium hydroxide, crystallization temperature and initial water content in synthesis mixtures were investigated considering their distinct effects on the dissolution and crystallization processes. It has been found that the intracrystalline macropores could be only formed via precise controlling of the velocity difference between the outside-in dissolution of MSS and the crystallization of Silicalite-1 zeolite. Based on the recognition of the fabrication mechanism, further modified Silicalite-1 with much higher porosity (meso-/macropore volume was increased from 0.15 to 0.26 cm3 g−1) was synthesized successfully. Owing to the introduction of macropores and mesopores, the concentration and accessibility of active hydroxyl groups as well as the diffusion properties over hierarchical Silicalite-1 were both significantly enhanced and improved. And therefore, the hierarchical samples showed higher catalytic activities and superior catalyst lifetimes in the Beckmann rearrangement of cyclohexanone oxime compared to conventional microporous Silicalite-1. The present study provides a new understanding of the evolution mechanism of amorphous precursors to hierarchical zeolites in a secondary-template-free system, which is of great significance for the development of direct fabrication methods towards hierarchical zeolites and the Beckmann rearrangement reaction.

In this study, detailed investigations about a novel dissolution–crystallization synthetic route for the fabrication of hierarchically macro/microporous ZSM-5 single crystals were conducted. During the fabrication, pre-prepared mesoporous aluminosilicate spheres (MASS) acted not only as raw materials but also as quasi “scaffold templates” simultaneously to construct additional macropores. Factors like the amount of alkali sodium hydroxide (NaOH), crystallization temperature and Si/Al ratios of MASS could affect the successful fabrication of such hierarchical zeolites via varying either the dissolution behaviors of precursors or the crystallization of zeolite crystals. Generally, only with suitable amounts of alkali NaOH that matched the Si/Al ratios of precursors and at appropriate crystallization temperature could the balance between the dissolution and crystallization of MASS precursors be achieved and thus the intracrystalline macropores be constructed. Owing to the introduction of rich intracrystalline macropores, the diffusional properties of the hierarchical ZSM-5 crystals were significantly enhanced, which has also been well proved through the toluene adsorption experiment with an intelligent gravimetric analyzer. Thus, with a similar Zn-modification, all the three hierarchical samples with different Si/Al ratios exhibited a much longer lifetime and higher aromatics selectivity in the MTA reactions than the conventional microporous sample.

Environmentally-friendly zeolites have been used commercially to replace concentrated sulfuric acid and oleum in the alkylation reactions and dehydration of alcohols. However, moderate activity, associated with access and diffusion limitations, low intramolecular dehydration selectivity, associated with unsatisfactory acidity, and unknown reusability have hampered their industrial implementation in the dehydration of bulky 2-(4′-ethylbenzoyl)benzoic acid (E-BBA) to 2-ethylanthraquinone (2-EAQ). Herein, we have discovered that after being treated with mild HNO3, nano-sized H-Beta zeolite showed outstanding catalytic activity, selectivity and reusability, compared with a commercial oleum catalyst. A number of techniques, such as XRD, XPS, XRF, 29Si MAS NMR, 27Al MQ MAS NMR, FTIR, NH3-TPD, argon physisorption and HR-TEM, have been employed to decouple the interdependence between acidity, porosity and catalytic performance. It was found that mild HNO3 treatment could clean out the extra-framework aluminium deposits and selectively extract the aluminium species on the outer surface of Beta zeolites, which strengthened the acidity of the Bronsted acid sites (Si(OH)Al) inside the H-Beta micropores, thus increasing the possibility of intramolecular dehydration of E-BBA. Moreover, this mild HNO3 treatment also dredged the network of intercrystalline mesopores, alleviating the diffusion constraints. Therefore, through the dual adjustment of acidity and porosity, dealuminated H-Beta zeolite has a promising future in the green synthesis of 2-EAQ.

Nitrogen-containing organic chemicals such as amines, amides, nitriles, and hydrazones are crucial in chemical and medical industries. This paper reports a direct synthesis of N,N-dimethyl cyanamide [(CH3)2NCN] and amino acetonitrile (NH2CH2CN) through a methane/ammonia (CH4/NH3) coupling reaction triggered by dielectric barrier discharge plasma, with by-products of hydrazine, amines, and hydrazones. The influence of CH4/NH3 molar ratio, feedstock residence time, and specific energy input on the CH4/NH3 plasma coupling reaction has been investigated and discussed. Under the optimized conditions, the productivities of (CH3)2NCN and NH2CH2CN reached 0.46 and 0.82 g·L–1·h–1, respectively, with 8.83% CH4 conversion. In addition, through combining the optical emission spectra diagnosis and the reaction results, a possible CH4/NH3 plasma coupling reaction mechanism has been proposed. This paper provides a potential fine application of CH4 and NH3 in green synthesis of liquid nitrogen-containing organic chemicals, such as nitriles, amines, amides, and hydrazones.

The selective oxidation of methane to methanol (SOMTM) by molecular oxygen is a holy grail in catalytic chemistry and remains a challenge in chemical industry. We perform SOMTM in a CH4/O2 plasma, at low temperature and atmospheric pressure, promoted by Ni-based catalysts, reaching 81 % liquid oxygenates selectivity and 50 % CH3OH selectivity, with an excellent catalytic stability. Chemical kinetics modelling shows that CH3OH in the plasma is mainly produced through radical reactions, i.e., CH4 + O(1D) → CH3O + H, followed by CH3O + H + M→ CH3OH + M and CH3O + HCO → CH3OH + CO. The catalyst characterization shows that the improved production of CH3OH is attributed to abundant chemisorbed oxygen species, originating from highly dispersed NiO phase with strong oxide support interaction with γ-Al2O3, which are capable of promoting CH3OH formation through E-R reactions and activating H2O molecules to facilitate CH3OH desorption.

CO2 hydrogenation to methanol is a promising process for CO2 conversion and utilization. Despite a well-developed route for CO hydrogenation to methanol, the use of CO2 as a feedstock for methanol synthesis remains underexplored, and one of its major challenges is high reaction pressure (usually 30–300 atm). In this work, atmospheric pressure and room temperature (∼30 °C) synthesis of methanol from CO2 and H2 has been successfully achieved using a dielectric barrier discharge (DBD) with and without a catalyst. The methanol production was strongly dependent on the plasma reactor setup; the DBD reactor with a special water-electrode design showed the highest reaction performance in terms of the conversion of CO2 and methanol yield. The combination of the plasma with Cu/γ-Al2O3 or Pt/γ-Al2O3 catalyst significantly enhanced the CO2 conversion and methanol yield compared to the plasma hydrogenation of CO2 without a catalyst. The maximum methanol yield of 11.3% and methanol selectivity of 53.7% were achieved over the Cu/γ-Al2O3 catalyst with a CO2 conversion of 21.2% in the plasma process, while no reaction occurred at ambient conditions without using plasma. The possible reaction mechanisms in the plasma CO2 hydrogenation to CH3OH with and without a catalyst were proposed by combined means of electrical and optical diagnostics, product analysis, catalyst characterization, and plasma kinetic modeling. These results have successfully demonstrated that this unique plasma process offers a promising solution for lowering the kinetic barrier of catalytic CO2 hydrogenation to methanol instead of using traditional approaches (e.g., high reaction temperature and high-pressure process), and has great potential to deliver a step-change in future CO2 conversion and utilization.

The isomerization of n-heptane was studied over highly dispersed Pt/Silicalite-1 catalysts, and significantly higher n-heptane conversion and isomerization selectivity were achieved when compared with Pt/SiO2 catalysts. The outstanding performance of Pt/Silicalite-1 catalysts was attributed to the high dispersion of Pt on Silicalite-1, the strong interaction between Pt nanoparticles and Silicalite-1, and the stronger n-heptane adsorption capacity on the catalysts.

Direct synthesis of hydrogen peroxide (H2O2) from H2 and O2 is an ideal route. H2/O2 plasma has a great potential for direct synthesis of high purity H2O2 without purification operations. However, low yield and high energy consumption limits the application of H2/O2 plasma in industry. This article reports that gas state Ar and H2O molecule serving as molecular catalysts promoted the synthesis of H2O2 from H2/O2/Ar/H2O plasma dramatically: the H2O2 yield was enhanced by 244% and the energy consumption was reduced by 70.9%. Ar not only increased the electron density, but also selectively accelerated the dissociation of H2 toward the formation of •HO2, a key intermediate species in H2O2 synthesis. While H2O facilitated the formation of •HO2 radical and stabilized it by forming a HO2•H2O complex, resulting in enhancing the H2O2 production. This single molecular catalysis reduced the cost of H2O2 synthesis more than 50%. © 2017 American Institute of Chemical Engineers AIChE J, 2017

The isomerization of n-heptane was comparatively investigated over Pt catalysts prepared by deposition (Pt/S-1-DP) and impregnation precipitation (Pt/S-1-IMP) method with a low loading, separately. It was found that Pt/S-1-DP catalyst produced a much higher catalytic conversion compared with the counterpart catalyst prepared by impregnation. Combined with various characterization techniques, the better performance over Pt/S-1-DP was attributed to not only the well improved dispersity and the smaller size of Pt particles but also the faster transfer of reactive species between Pt sites and acid sites. The activity could be improved by increasing the reduction temperature. Moreover, the (de)hydrogenation of Pt over Pt/S-1 catalyst was verified by in situ infrared spectroscopy through H/D isotope exchange experiment.

A reduced graphene oxide (RGO) based capacitive real time bio-sensor was presented. Suspended graphene oxide (GO) film was assembled electrophoretically between the source and drain electrodes of a transistor and then reduced by annealing in hydrogen/nitrogen forming gas to optimize the surface functional groups and conductivity. The resonance frequency of the transmission coefficient (S21) of the transistor was observed to shift with deoxyribonucleic acid (DNA)-hybridization, with a detecting limit of ~ 5 nM. The advantages of the bio-sensing approach include low-noise frequency output, solution based real time detection and capable of on-chip integration.

An operando dual-beam Fourier transform infrared (DB-FTIR) spectrometer was successfully de-veloped using a facile method. The DB-FTIR spectrometer is suitable for the real-time study of the dynamic surface processes involved in gas/solid heterogeneous catalysis under real reaction condi-tions because it can simultaneously collect reference and sample spectra. The influence of gas-phase molecular vibration and heat irradiation at real reaction temperatures can therefore be eliminated. The DB-FTIR spectrometer was successfully used to follow the transformation of isobutene over nano-sized HZSM-5 zeolite under real reaction conditions.

Hierarchical aluminosilicate-based MFI zeolite single crystals with intracrystalline macropores were fabricated in one pot for the first time. The strategy involved the outward dissolution of the aluminosilicate precursor and simultaneous recrystallization of Si and Al species under the guidance of the organic template tetrapropylammonium bromide. The interesting outward dissolution of the aluminosilicate precursor from core to shell led to the formation of intracrystalline macropores. The Si/Al ratios of these macro/microporous ZSM-5 single crystals could be easily tuned in a wide range by varying the aluminum and alkali contents of the aluminosilicate precursors. The hierarchical ZSM-5 zeolite with highly interconnected macropores exhibited high performance in the 1,3,5-triisopropylbenzene cracking reaction due to the improved intracrystalline diffusion. This study provides a new strategy to fabricate highly efficient zeolites with hierarchical porosity in a simple and cost-effective way.

In this study, phosphorus modification by trimethyl phosphate impregnation was employed to enhance the hydrothermal stability of nano-sized HZSM-5 zeolites. A parallel modification was studied by ammonium dihydrogen phosphate impregnation. The modified zeolites were subjected to steam treatment at 800 °C for 4 h (100% steam) and employed as catalysts for olefin catalytic cracking (OCC) of full-range fluid catalytic cracking (FCC) gasoline. X-ray diffraction, N2 physical adsorption and NH3 temperature-programmed desorption analysis indicated that, although significant improvements to the hydrothermal stability of nano-sized HZSM-5 zeolites can be observed when adopting both phosphorus modification strategies, impregnation with trimethyl phosphate displays further enhancement of the hydrothermal stability. This is because higher structural crystallinity is retained, larger specific surface areas/micropore volumes form, and there are greater numbers of surface acid sites. Reaction experiments conducted using a fixed-bed micro-reactor (catalyst/oil ratio = 4, time on stream = 4 s) showed OCC of full-range FCC gasoline—under a fluidized-bed reaction mode configuration—to be a viable solution for the olefin problem of FCC gasoline. This reaction significantly decreased the olefin content in the full-range FCC gasoline feed, and specifically heavy-end olefins, by converting the olefins into value-added C2–C4 olefins and aromatics. At the same time, sulfide content of the gasoline decreased via a non-hydrodesulfurization process. Nano-sized HZSM-5 zeolites modified with trimethyl phosphate exhibited enhanced catalytic performance for OCC of full-range FCC gasoline.

A series of ZnSnPt supported defective MFI zeolites with different SiO2/Al2O3 ratios (30, 110, 700, and &infin, ) and hydroxyl nests concentration were prepared and characterized by multiple techniques including scanning electron microscopy (SEM), nitrogen physisorption, NH3-TPD, transmission electron microscopy (TEM), hydrogen temperature programmed reduction (H2-TPR), and Fourier transform infrared spectrometer (FT-IR). It was found that Br&oslash, nsted acid sites (Si(OH)Al) with strong acid strength and the hydroxyl nests with weak acid strength coexisted over the defective ZSM-5 zeolites and ZnSnPt Lewis acid sites preferentially located on the hydroxyl nests. The increase in the concentration of hydroxyl nests and SiO2/Al2O3 ratios apparently improved the distribution of ZnSnPt Lewis acid sites. The hydroxyl nest incorporated ZnSnPt Lewis acid sites showed extraordinary dehydrogenation ability. Specially, operando dual beam Fourier transform infrared spectrometer (DB-FTIR) was applied to characterize the propane transformation under reaction conditions. At low SiO2/Al2O3 ratios, the propane efficiently transforms into propene and aromatics (total selectivity of 93.37%) by the cooperation of Br&oslash, nsted acid sites and ZnSnPt Lewis acid sites. While at high SiO2/Al2O3 ratios, the propane mainly transforms into propene (selectivity of above 95%) and hydrogen. This study provides guidance for the preparation of highly efficient propane dehydrogenative transformation catalyst.

A series of defective ZSM-5 zeolites (~300 nm, SiO2/Al2O3 ratio of 55, 100, 480 and 950) were systematically studied by XRD, SEM, 29Si MAS NMR, argon physisorption, NH3-TPD and FT-IR technologies. The nature, the amount and the accessibility of the acid sites of defective ZSM-5 zeolites are greatly different from reported ZSM-5 zeolites with a perfect crystal structure. The Br&oslash, nsted acid sites (Si(OH)Al) with strong acid strength and the Br&oslash, nsted acid sites (hydroxyl nests) with weak acid strength co-existed over defective ZSM-5 zeolites, which leads to a unique catalytic function. Zn(C2H5)2 was grafted onto defective ZSM-5 zeolites through the chemical liquid deposition (CLD) method. Interestingly, FT-IR spectroscopic studies found that Zn(C2H5)2 was preferentially grafted on the hydroxyl nests with weak acid strength rather than the Si(OH)Al groups with strong acid strength over different defective ZSM-5 zeolites. In particular, home-built operando dual beam FTIR-MS was applied to study the catalytic performance of Zn species located in different sites of defective ZSM-5 zeolites under real n-hexane transformation conditions. Results show that Zn species grafted over hydroxyl nests obtain better dehydrogenative aromatization performance than Zn species over Si(OH)Al groups. This study provides guidance for the rational design of highly efficient alkane dehydrogenative aromatization catalysts.

Object detection refers to the classification and localization of objects within an image by learning their diversified features. However, the existing detection models are usually sensitive to the important features in some local regions of the object. The existing algorithms cannot learn the diversified features regarding to each region effectively, which limit the performance of the model to a certain range. In this paper, we propose a novel and principle method called Multi-region Occlusion Example Generating (MOEG) to guide the detection model in fully learning the features of the various regions of the object. MOEG can generate completely new occlusion examples and it enables our detection model to learn the features of the remaining regions in the object by blocking the important regions in the proposal. It is a general method to generate occlusion examples and it can be implemented to most mainstream region-based detectors very easily such as Fast-RCNN and Faster-RCNN. Our experimental results indicate a \(2.4\%\) mAP boost on VOC2007 dataset and a 4.1% mAP boost on VOC2012 dataset compared to the Fast-RCNN pipeline. And as datasets become larger and more challenge, our method MOEG become more effective as demonstrated by the results on the MS COCO dataset.

The sluggish interfacial mass transfer usually hinders the achievement of high-efficiency catalytic transformation of biomass, especially for solvent-free immiscible reagent systems. Herein, amphiphilic hybrid Ti-containing catalysts in situ incorporated with organic groups (Cn-Ti-HMS) were developed for boosting biphasic solvent-free epoxidation of methyl oleate (MO) with H2O2. Benefiting from the mutual effect between organic/inorganic precursors, the resulting low-defect catalysts exhibit well-mediated surface hydrophilic/hydrophobic balance and porosity by incorporating alkyl groups. Such mediation effect exhibits two superiorities: i) accelerated adsorption of reactants by amphiphilicity; ii) boosted substrate or product diffusion by porosity property. As such, remarkably promoted catalytic properties were achieved when compared with conventional Ti-HMS. Typically, methyl-functionalized C1–Ti-HMS-50 displays the optimal catalytic performance with a 95% conversion of MO. Further mechanism study recognizes the dominant role of surface wettability and Si–OH defects content in influencing MO conversion and epoxidized MO selectivity.

The utilization of porous carbon frameworks as hosts for sulfur loading is an important theme in current Li-S battery research. Unfortunately, the high loading of insulating sulfur often leads to low specific capacities, poor rate properties, and rapid capacity loss. To address this challenge, a facile templating route to fabricate a novel host material, hierarchical porous carbon rods constructed by vertically oriented porous graphene-like nanosheets (HPCR) is presented. With a high specific surface area, ultralarge pore volume, hierarchical porous structures, and ideal ion transfer pathways, HPCR is a promising candidate for high sulfur loading. When used as the active material for a sulfur cathode, the HPCR-S composite with 78.9 wt% sulfur exhibits excellent rate performance (646 mAh g−1sulfur at 5 C) and cycling stability (700 mAh g−1sulfur after 300 cycles at 1 C). Even with a sulfur content of 88.8 wt%, the HPCR-S composite, without any additional protective polymer coating, still delivers a good rate performance (545 mAh g−1sulfur at 3 C) and cycling stability (632 mAh g−1sulfur after 200 cycles at 1 C). More importantly, the high sulfur loading (88.8 wt%) ensures that the HPCR-S composite has a high energy density (880 mAh cm−3cathode after 200 cycles at 1 C).

Reduced graphene oxide (rGO)/ZnO heterostructure was prepared via electrochemical deposition directly on Hummers method derived rGO membranes and the corresponding diodes had been fabricated. Rectifying I–V curve was obtained by modifying the functional groups on the surface of rGO. Further investigation for GO based transistors showed that the conductivity of rGO could vary from n-type to p-type under different annealing conditions. Based on Lerf-Klinowski model and X-Ray photoelectron spectroscopy, it was found that the C-sp 2 , hydroxyl and epoxy in rGO would be responsible for the change of electrical properties. It was also concluded that reasonable p-type conductivity of rGO for obtaining rectifying rGO/ZnO heterostructure occurred while the percentage of C-sp 2 content was about 54% with the C-sp 2 /(OH + C-O-C) ratio around 1.6.

Hydrogen peroxide (H2O2) as a highly efficient and green oxidant has become one of the 100 most important chemicals in the world. Some current research progress in the direct synthesis of H2O2 from H2 and O2 by noble-metal catalyst, fuel cell and plasma methods has been reviewed systematically in this paper. Perspectives about the development direction and application prospect of the above-mentioned three methods have also been discussed.

Mesoporous carbon fiber cloth has been developed via a rapid noble metal nanoparticles induced thermal etching. The specific surface area was increased while the electrochemical performance has been also improved. It has been found that the metal nanoparticles induced thermal etching can hardly break the C-sp 2 honeycomb structure but would be towards the boundaries and. The noble metal induced etching would be a novel approach to modify the surface and defects.