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To upgrade pyrolysis vapors derived from the catalytic fast pyrolysis (CFP) of Baiyinhua lignite (BYHL) in a drop tube reactor, various Co-loading (1, 3, 6 and 10 wt%) zeolites were prepared via wet impregnation. The effect of Co-loading and pyrolysis temperature ranged from 400 to 700 °C on product yields and tar properties were investigated in this work. The results showed that the product yield and the composition of pyrolysis tar were significantly affected by Co-modified HZSM-5 and parent HZSM-5 compared with no catalyst. Incorporation of metal-Co in HZSM-5 had an additional effect on the performance of the parent HZSM-5. The total content of benzene (B), toluene (T), ethylbenzene (E), xylene (X) and naphthalene (N) significantly increased and it reached 24.2 mg/g at Co-loading of 3 wt% (3Co-H-5) at 600 °C. 3Co-H-5 exhibited also a promising performance in lowering the oxygen content from 49.8% without a catalyst to 14.6% by GC–MS analysis. The deoxygenation mechanisms over metal-Co active centers and acid-catalyzed reactions, such as isomerization and cracking, over acid sites of HZSM-5 were speculated in this work. In addition, the temperature of 600 °C is not only appropriate for fast pyrolysis of lignite to obtain a higher pyrolysis tar, but also for catalytic pyrolysis to obtain BTEXN. [ABSTRACT FROM AUTHOR]

Lignite, a suitable feedstock for direct coal liquefaction (DCL), is usually rich in sodium and calcium species. To better understand chemical transformation of inherent sodium and calcium species during DCL, two lignites rich in sodium and calcium species were liquefied in this work. The results show that both Australia lignite (AU) and Hami lignite (HM) are preferred raw materials for DCL. After DCL, mineral matters were obviously enriched in residues (DCLR). Under all the temperatures, retention ratios of sodium species were lower than those of calcium species. One obvious transformation of calcium species was reflected in changes of organic-bound calcium species (AS-Ca) and hydrochloric acid-insoluble calcium species (HIS-Ca) in HM. During direct liquefaction of HM, the amount of AS-Ca decreased significantly and the amount of HIS-Ca increased sharply. XRD analyses of low temperature ashes of DCLR confirmed that when temperatures reached above 400 °C, kaoline in HM gradually decomposed and came to react with AS-Ca, which resulted in formation of HIS-Ca. Due to the low ash content, transformation of calcium species in AU showed unobvious tendency and only CaCO 3 was detected in DCLR. [ABSTRACT FROM AUTHOR]

Directional depolymerization of lignin represents an essential process to produce value-added aromatic compounds. The catalyst obtained by adjusting the hydrophobicity of the support can regulate the reaction pathway and products selectivity for the cleavage of lignin-related compounds. Hydrophilic modification of activated carbon (AC) using trimethylchlorosilane (TMCS) was developed to decrease the hydrophilicity of carbon-based catalyst. The contact angle of the carrier dramatically increased from 43o to 130o after modified. AC was modified with an appropriate amount of TMCS and loaded with Ni to prepare Ni/10% TMCS-AC, which could effectively inhibit the hydrolysis of diphenyl ether (DPE) and the over‑hydrogenation of products. The selectivity of monocyclic aromatics (benzene and phenol) over Ni/10% TMCS-AC increased 30% compared with the unmodified Ni/AC. TMCS occupied part of the adsorption sites, which prevented the Ni from adsorbing more active hydrogen and inhibited the hydrogenation of benzene and phenol. Meanwhile, the hydrolysis of DPE was inhibited and the hydrogenolysis reaction pathway of DPE was over 90% than Ni/AC. The construction of the hydrophobic Ni/10% TMCS-AC highlighted a promising way to convert DPE to aromatic chemicals. [Display omitted] • Adjusting the hydrophilicity of AC modulates the reaction path and product selectivity. • Using trimethylchlorosilane to decrease the hydrophilicity of carbon-based catalyst. • Ni/10% TMCS-AC inhibits hydrolysis of DPE and over‑hydrogenation of products. • The reaction route over Ni/10% TMCS-AC and Ni/AC were presented. [ABSTRACT FROM AUTHOR]

A series of porous carbons (PCs) were obtained from Shengli lignite (SL) via hydrothermal carbonization (HTC) pre-treatment and followed by chemical activation with KOH. The effects of preparation parameters including HTC temperature, KOH-hydrochar ratio and activation temperature on pore structure and the electrochemical performances of PCs were investigated in details. The PCs are mainly micropores structure according to the N 2 adsorption-desorption isotherms test and the highest specific surface area (SSA) is up to 3162 m 2 g −1 . The SSA and total pore volume of PCs with HTC pre-treatment are larger than that without HTC treatment. The electrochemical performances of the symmetric electric double layer capacitor (EDLC) fabricated from these PC electrodes were tested by galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy. All the PCs as electrode for EDLC exhibit ideal capacitive behaviors in 6 M KOH electrolyte. The specific capacitance of 200-HTC-800-3 can reach as high as 295 F g −1 at the current density of 40 mA g −1 and still retained 210 F g −1 at the current density of 10 A g −1 . It also shows excellent electrochemical cycle performance that after 15000 cycles the specific capacitance value almost not decay. The processes used to produce the PCs can reduce the energy consumption compared to the traditional carbonization-activation method. [ABSTRACT FROM AUTHOR]

A novel porous carbon catalyst was prepared by carbonization of D151 resin exchanged with nickel ion (Ni/RC). TEM images and XRD patterns manifest that nickel crystallite size (NCS) relies greatly on solution pH value and carbonization temperature. The as-prepared Ni/RC in pH 11 at 650 °C achieved the maximal specific surface area of 213 m 2 /g and metallic nickel particles are highly dispersed with a NCS of 5.7 nm. Ni/RC exhibited higher activity for corncob tar reforming than commercial Ni/Al 2 O 3 and produced a gas yield of 46.8 mmol/g at 650 °C. The nickel particles growth above 650 °C causes the decline in catalytic activity of Ni/RC. In the presence of steam, a high tar-free gas of 84.5 mmol/g was obtained at 650 °C. This study sheds light on the possibility of Ni/RC as a promising candidate for H 2 -rich gas production from biomass under mild conditions. [ABSTRACT FROM AUTHOR]

Waste sugar solution (WSS), which contains abundant 2-keto- l -gulonic acid, is harmful to the environment if discharged directly. For value-added utilization of the waste resource, a novel process is developed for preparation of porous carbon spheres by hydrothermal carbonization (HTC) of WSS followed by KOH activation. Additionally, the possible preparation mechanism of carbon spheres is proposed. The effects of hydrothermal and activation parameters on the properties of the carbon sphere are also investigated. The carbon sphere is applied to electric double-layer capacitor and its electrochemical performance is studied. These results show that the carbon sphere obtained by HTC at 180 °C for 12 h with the WSS/deionized water volume ratio of 2/3 possess the highest specific capacitance under identical activation conditions. The specific capacitance of the carbon spheres can reach 296.1 F g −1 at a current density of 40 mA g −1 . Besides, excellent cycle life and good capacitance retention (89.6%) are observed at 1.5 A g −1 after 5000 cycles. This study not only provides a facile and potential method for the WSS treatment, but also achieves the high value-added recycling of WSS for the preparation of porous carbon spheres with superior electrochemical properties. [ABSTRACT FROM AUTHOR]

Lignite is rich in oxygen-containing species (OCSs) and able to load Ni via ion exchange to prepare Ni/C catalyst. However, the OCSs usually exists in the form of organic salts, which can reduce the capacity of Ni ion exchange. In this paper, Shengli lignite (SL) was treated with HCl and HCl/HF to selectively remove the organic salts and insoluble minerals, respectively, and the modified lignite was oxidized by H 2 O 2 to further increase the carboxyl content. The treated lignite was used to prepare Ni/C catalyst and the activity for biomass volatile reforming was evaluated. The results show that demineralization (DM) caused the corrosion of pore structure of SL and gave a Ni/C catalyst with a low specific surface area (SSA) of 222.1 m 2 /g. Oxidation with H 2 O 2 further destroyed the structure of DMSL and provided a Ni/C with the lowest SSA of 141.1 m 2 /g. Acid wash (AW) with HCl resulted in the increase of ion exchange capacity of SL and gave a Ni/C catalyst with larger SSA, higher loading, lower particle size and well dispersion of Ni particle in comparison with SL and DMSL. H 2 O 2 treatment of AWSL significantly increased the amount of carboxyl group to 3.8 mmol/g and gave a Ni/C with the largest SSA of 291.1 m 2 /g, highest Ni loading of 17.3% and smallest Ni crystallite size of 3.4 nm, as well as most active for corncob volatile reforming. [ABSTRACT FROM AUTHOR]

Fast pyrolysis of pine sawdust (PS) was investigated in a drop tube quartz reactor to understand the effects of temperature and atmosphere (Ar and H 2 ) on the product yields, gas composition, bio-oil characteristics (organic composition and molecular mass distributions (MMDs)), and the carbon and oxygen conversion. The pyrolysis behavior and typical products from PS pyrolysis were also conducted using a thermogravimetry-mass spectroscopy (TG-MS) and pyrolysis-gas-chromatography/mass spectrometry (Py-GC/MS). The results show that the highest oil yields can be obtained at 500 °C of 55.09 and 54.41 wt.% under Ar and H 2 atmosphere, respectively. In comparison to an inert atmosphere, H 2 created lower oil yields but higher gas yields, especially for CO and CH 4 yields, and narrower MMDs, smaller M n and M w , and fewer char especially at high temperatures. The high temperatures and H 2 atmosphere contribute to the oxygen and carbon transferring from material to volatile, especially to the gaseous products. H 2 can promote the secondary cracking of macromolecules and weaken the re-polymerization of anhydrosugar and lignin oligomers. [ABSTRACT FROM AUTHOR]

Lignite-based porous carbon with clustered pore structure, large specific surface area (SSA) and high oxygen content is prepared by H 3 PO 4 hydrothermal followed by KOH activation, which uses Shengli lignite modified by acid washing followed with oxidization (OAWSL) as carbon precursor. A part of ash in lignite is removed and abundant oxygen-containing functional groups are introduced through HCl washing and H 2 O 2 oxidation. H 3 PO 4 introduces phosphorus into OAWSL and promotes the formation of pores, then plentiful micropores are further formed by KOH. The POPC-2, which shows the best performance, has a high SSA (2852 m2 g−1) and an oxygen content of 15.73 wt%, providing more charge capacity and active sites. In addition, the POPC-2 as an electrode for supercapacitors exhibits a high specific capacitance of 320 F g−1 at 1 A g−1 and 272 F g−1 at 30 A g−1 in a three-electrode system in 6 M KOH electrolyte. Futhermore, the symmetric supercapacitors based on POPC-2 also shows high specific capacitance of 390 F g−1 at 0.05 A g−1, an energy density of 10.75 Wh kg−1 and outstanding cycling stability with 88% of the initial capacitance retention after 25,000 cycles at 2 A g−1. [Display omitted] • Shengli lignite was modified by acid washing and oxidation. • H 3 PO 4 hydrothermal promoted the development of pores. • Specific capacitance of 320 F g−1 at 1 A g−1 and 272 F g−1 at 30 A g−1 were achieved. • Outstanding cycling performance of 88% after 25,000 cycles at 2 A g−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Selective hydrogenation of arenes is achieved at room temperature over Rh/α-Al 2 O 3. • Rh-1/α-Al 2 O 3 exhibits the highest performance for the conversion of DPE and toluene. • The metal Rh nanoparticles are distributed on α-Al 2 O 3 for Rh-1/α-Al 2 O 3. • The strong adsorption capacity of toluene and guaiacol occurs on Rh (2 0 0). • The routes for the hydrogenation of DPE, toluene and guaiacol are presented. Selective hydrogenation of arenes is a crucial process not only for the hydrogen storage and transport but also for the synthesis of important pharmaceutical intermediates. Herein, a series of α-Al 2 O 3 -supported catalysts prepared using different metals were tested for the arenes hydrogenation of lignin derivatives at room temperature. The kinetic studies reveal that Rh-1/α-Al 2 O 3 exhibits both the highest reaction rate and TOF value for the conversion of diphenyl ether and toluene. The XRD, TEM, XPS and XAS characterizations suggest that the metal Rh nanoparticles dispersed on α-Al 2 O 3 support for Rh-1/α-Al 2 O 3 catalyst is mainly responsible for the H 2 activation/dissociation and subsequent arenes hydrogenation. The density functional theory calculation indicates the stronger adsorption capacity of toluene and guaiacol on Rh (2 0 0) than that on Rh (1 1 1) and Rh (2 2 0). Stable Rh-1/α-Al 2 O 3 can contribute to the improvement of the arenes hydrogenation of lignin derivatives to produce high-value-added platform chemicals at room temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Modified lignite can serve as a potential material for metal ions recovery. • The facile co-ion exchange method can effectively avoid metal agglomeration. • Co-Cu/C shows excellent catalytic activity and stability under low temperature. • The addition of Cu contributes to lower Co particle size (4.17 nm). • The formation of Co-Cu alloy promotes the resistance to deposited carbon and oxidation. Recovering beneficial metal ions from industrial effluents by suitable support can be an efficient and environment-friendly way to prepare specific catalysts directly. Herein, modified lignite was developed as an ion exchange material and used to prepare Co-Cu bimetallic catalysts for hydrogen-rich syngas production from steam reforming reactions. For all the catalysts studied, Co 75 Cu 15 /600 (carbonization temperature at 600 °C) exhibits the optimal catalytic activity and stability in both steam reforming of toluene and biomass tar under low temperatures. Fresh and spent catalysts were detailedly characterized to investigate the metal interactions and catalyst deactivation. The introduction of Cu contributes to the formation of Co-Cu alloy and the lower particle size of Co (4.17 nm), thereby suppressing the carbon deposition, the oxidation of metals and the change of catalyst structure after reaction. Therefore, the inexpensive and readily-available Co-Cu/C has the potential to serve as a promising catalyst for large-scale biomass gasification technology. [ABSTRACT FROM AUTHOR]

• Simple method for the preparation of highly-dispersed Co-based catalysts. • Co 0.15 -C 2 H 3 O 2 − has high Co loading (16 wt%) and small metallic particles (3.77 nm). • 98.7 % toluene conversion was achieved at 400 °C over Co 0.2 -C 2 H 3 O 2 −. • Co 0.15 -C 2 H 3 O 2 − exhibits excellent stability during 100 h reforming test. • Co 0.15 -C 2 H 3 O 2 − help to produce 283.8 mL.g corncob −1.g cat −1.h−1 H 2 at 480 °C. The removal of generated tar during the biomass gasification is a serious issue. Catalytic tar cracking is one of the most efficient methods to reduce tar deposition while many common tar cracking catalysts suffer problems of serious carbon deposition and active metal sintering, especially at low temperatures. Therefore, developing catalysts with both high activity and stability is critical. In this work, we aim to prepare catalysts with a high active metal contents, a small metal particle size and a high dispersion to contribute to the highly efficient tar removal at relatively low temperatures. By adjusting the type and the concentration of the Co precursor solution when lignite is used as the carbon precursor, we prepared a series of catalysts which were then applied for both activity and stability test of the steam reforming of model tar and biomass tar. The results show that Co 0.15 -C 2 H 3 O 2 − prepared with a 0.15 M solution of Co(C 2 H 3 O 2) 2 ·4H 2 O achieves a Co content of about 16.0 wt% with an average particle size of about 3.77 nm and a relatively high metallic Co dispersion. For steam reforming of toluene, the catalyst achieves an almost 100 % toluene conversion at 400 °C and exhibits a high stability in the 100 h test. Moreover, Co 0.15 -C 2 H 3 O 2 −, which produces approximately 283.8 mL.g corncob −1.g cat −1.h−1 H 2 catalytically, is also active and stable in biomass tar cracking. The catalyst prepared in the present study by using the economic and simple ion-exchange method also has a well-dispersed nano-metal-loaded structure and can efficiently remove the tar at a low temperature with a high stability, which will contribute to the industrial application in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coal tar pitch was oxidized by KMnO 4. • Nitrogen precursors were synthesized by chemical oxidative polymerization. • Nitrogen-doping three-dimensional hydrangea-like porous carbons was prepared. • High energy density (56.4 Wh kg−1) in EMIMBF 4 electrolyte. Nitrogen-doping three-dimensional hydrangea-like porous carbons (NHPCs) were prepared by coal tar pitch oxidized by KMnO 4 (OCTP) as carbon precursor and p-phenylenediamine (pPDA) as nitrogen source. The terminal amine group on the pPDA and the oxygen-containing functional group on the OCTP were grafted together by chemical oxidative polymerization. Not only successfully achieved nitrogen-doping, but also the benzene ring in pPDA could occupy the branching space of polycyclic aromatic hydrocarbons in OCTP and reduce its irreversible accumulation. The as-prepared NHPCs showed a unique three-dimensional hydrangea-like structure, which could provide large specific surface area (2237 m2 g−1), abundant micro/mesopores and high nitrogen content (3.7%). Remarkably, NHPC-600 exhibited excellent electrochemical performance as the electrode material of supercapacitors, such as a high specific capacitance up to 423 F g−1 at 0.1 A g−1 and long cycle stability (maintaining 94.3% of the initial capacitance after 10,000 cycles) in 6 M KOH. Simultaneously, NHPC-600 achieved a higher working voltage (3.6 V) in EMIMBF 4 electrolyte, thereby obtaining a high energy density (56.4 Wh kg−1). [ABSTRACT FROM AUTHOR]

Selective hydrogenolysis of lignin-derived compounds is a significant process to produce value-added chemicals and the design of the high active catalyst is challenging. Biochar was used as potential supports of heterogeneous catalysts due to its high porosity. Biochar prepared from different carbon sources had different effects on the dispersion and reduction of metallic Ni due to their different physical structure and elemental composition, resulting in the difference in catalytic performance. Herein, biochar obtained from biomass waste, cellulose powder, hemicellulose, and lignin were used as the support of catalysts. The effect of biochar with different carbon sources on the catalytic hydrogenolysis of lignin model compounds over Ni/AC catalyst was investigated. Among these catalysts, Ni/ACP prepared from cellulose powder exhibited the best catalytic activity for converting lignin-derived compounds into value-added compounds under mild conditions (140 °C and 1 MPa H 2). ACP with uniform pore structure could make Ni a better dispersion. The high purity sulfur-free ACP could therefore embrace more Ni0. These characteristics of Ni/ACP resulted in the optimal catalytic performance compared to other Ni/AC catalysts. Meanwhile, Ni/ACP was also used to explore the hydrogenolysis of other lignin model compounds to evaluate the applicability of the catalysts. [Display omitted] • Biochar prepared from different carbon sources was used as the catalyst support. • Ni supported on biochar prepared from cellulose had high catalytic performance. • The high activity of Ni/ACP is due to high surface area and sulfur-free of ACP. • The hydrogenolysis route over Ni/ACP was presented. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of aromatic ring represents an essential process for the valorization of lignin in the chemical industry but achieving this process at low temperature is still a challenge. Herein, a series of Ru-based catalysts were investigated. It is found that Ru/γ-Al 2 O 3 with small Ru metal particle size shows the low activity in this system. A unique and strong metal-support interaction for Ru/γ-Al 2 O 3 indicates that the strongly bounded Ru-O-Al sites lead to the positive charge of Ru species. In contrast, Ru/α-Al 2 O 3 with well-dispersed Ru nanoparticles supported on α-Al 2 O 3 can successfully catalyze the selective hydrogenation of lignin-derived aromatic compounds at room temperature. Ru/α-Al 2 O 3 has the excellent recyclability, air stability and the highest activity. The selective hydrogenation of aromatic ring for Ru/α-Al 2 O 3 results from the fast dissociation of H 2 and the high adsorption energy of aromatic ring as revealed by X-ray absorption spectra, X-ray photoelectron spectroscopy and density functional theory calculations. [Display omitted] • Aromatic ring hydrogenation was achieved at room temperature over Ru/α-Al 2 O 3. • H 2 rather than solvents provided the only hydrogen source in this reaction. • The fast H 2 dissociation and high DPE adsorption energy occurred on Ru/α-Al 2 O 3. • More metal Ru exists in Ru/α-Al 2 O 3 and positively charged Ru exists in Ru/γ-Al 2 O 3. • The reaction route of the aromatic ring hydrogenation for DPE was presented. [ABSTRACT FROM AUTHOR]

Catalytic gasification (CG) of sewage sludge-derived volatiles (SSDVs) was investigated over a prepared nickel loaded on Loy Yong lignite char (Ni/LYLC) in a two-stage fixed-bed reactor to understand the effects of the catalyst, temperature, and steam on the gas yields and nitrogen transformations. Non-catalytic thermal decomposition of SSDVs below 650 °C is not effective for decomposing the tar and converting the volatile nitrogen species (VNSs) to N2. Ni/LYLC proved to be quite active not only for tar reduction, but also for the conversion of VNSs to N2 at 650 °C. CG of SSDVs over Ni/LYLC produced significant amount of clean H2-rich syngas. CG above 650 °C results in the increase of nickel crystallite size and the deactivation of Ni/LYLC for tar decomposition. The study revealed the possibility of using Ni/LYLC as a potential catalyst for low-temperature CG of sewage sludge to produce clean H2-rich syngas. [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalysts of Ru supported on AC from coal tar pitch were successfully synthesized. • Ru/4-1AC exhibited the best catalytic performance for the cleavage of C-O bonds. • BPE was preferentially adsorbed on Ru metal for the C-O bond cleavage than DPE. • The reaction pathways of DPE and BPE were explored and analyzed in detail. • Oxygenated low-molecular-weight products were obtained from lignin over Ru/4-1AC. Selective hydrogenolysis of C-O bonds in lignin is regarded as the most promising strategy to produce high value-added biofuels and chemicals. Herein, Ru/AC catalysts of Ru supported on AC from coal tar pitch were successfully prepared and could effectively promote the cleavage of C-O bonds in diphenyl ether (DPE), benzyl phenyl ether (BPE) and lignin under mild conditions. In the case of an activation ratio of 4:1, the obtained Ru/4-1AC possessed the large specific surface area, more defects, small Ru metal particle size and low Ru0 bonding energy, exhibiting the high catalytic performance. The conversion investigation of the mixture of DPE and BPE revealed that BPE was preferentially adsorbed on Ru metal of the catalyst surface for the C-O bond cleavage due to the lower bond dissociation energy of C-O bonds of BPE and the stronger adsorption energy of BPE calculated by a density functional theory. [ABSTRACT FROM AUTHOR]

Rod-shaped HSUZ-4 zeolite is discovered with distinctive activity and stability for DME carbonylation, which is dominated by the acid concentration and the number of 8-MR pore openings. [Display omitted] • Both the surface architecture and acid distribution of HSUZ-4 zeolite can be precisely regulated. • The structure-performance correlations between HSUZ-4 zeolite and carbonylation performance were systematically studied. • The catalytic activity was determined by the synergistic effect of the acid concentration and the number of 8-MR pore openings. • T1-O12 site located in 8-MR channel was energetically favorable for catalyzing DME carbonylation. Carbonylation, an important reaction to realize controllable carbon chain growth by C–C coupling, is highly attractive but challenging due to the rapid deactivation behavior. HSUZ-4 zeolite is a new candidate with a high durability for catalyzing dimethyl ether (DME) carbonylation. However, its industrial application is still impeded because of the low activity. In the present paper, the activity of DME carbonylation over rod-shaped HSUZ-4 zeolite can be significantly improved by adjusting the acid distribution. Results show that the DME carbonylation performance over rod-shaped HSUZ-4 zeolite was determined by the synergistic effect of the acid concentration and the number of 8-MR pore openings. Furthermore, we firstly revealed that the carbonylation reaction occurs preferentially at T1-O12 site located in 8-MR with a quantum-chemical method. Additionally, we discovered that the activity of HSUZ-4 zeolite can be further improved by promoting the crystal growth along the c axis because more 8-MR channels are exposed. This work will provide a detailed theoretical guidance for the rational designing and fabricating more efficient catalysts for the carbonylation reaction, which is highly attractive but remains challenge for the synthesis of C 2+ oxygenate chemicals from syngas and/or CO 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zn-containing HZSM-5 was synthesized by adding Zn(NO 3) 2 solution. • The addition of Zn affected pore volume and acidity of catalysts. • Direct incorporation of Zn species was beneficial to the generation of MAHs. • The highest BEX yield were produced over 0.7Zn(DS). A series of Zn-containing HZSM-5 (HZ5) with hierarchical pores (xZn(DS)) were obtained by adding different amounts of Zn(NO 3) 2 solution in a hydrothermal synthesis process. The performances of xZn(DS) in catalytic reforming of cellulose pyrolysis volatiles were investigated at 500 °C. The results showed that the addition of Zn during synthesis increased in the total pore volume of xZn(DS) and reduced the content of strong acid sites, and introduced new weak acid sites. The Zn species were highly dispersed inside the zeolite, and enhanced the accessibility of acid sites, so that the yields of light aromatic hydrocarbons and monocyclic aromatic hydrocarbons (MAHs) over 0.7Zn(DS) (The molar ratio of ZnO/Al 2 O 3 in the synthesis process of xZn(DS) was 0.7) were higher than those over S-HZ5 (Zn was not added in the synthesis process) and commercial HZ5. Compared with S-HZ5, the yield of MAHs over 0.7Zn(DS) increased from 92.8 to 114.1 mg/g and the coke yield decreased by 2.9%. The selectivity of MAHs over 0.7Zn(DS) was 87.7%, which was 5.3% higher than that over S-HZ5. Simultaneously, the increase in mesopores of xZn(DS) accelerated the mass transfer process, shortened the diffusion path and improved the anti-coking performance of the catalysts. In addition, this study also proposed a possible mechanism for the catalyst to adjust the distribution of aromatic products and provided a new idea for promoting the selective production of MAHs for the pyrolysis of cellulose. [ABSTRACT FROM AUTHOR]

[Display omitted] • Detailed review of tar reforming and downstream development. • Analysis of tar reforming pathways over different catalysts. • The review sheds light on active catalysts for tar elimination. • Possible integration of gasification and downstream technology. In the last few decades, the development of biomass energy has become a key research focus to press the emissions of greenhouse gas. Syngas production from biomass tar reforming in the presence of the heterogeneous catalyst has been proved to be a clean and promising technology, which could be further connected to the downstream for fuel valorization. Up to now, some literatures has screened the reaction pressure, temperature, atmosphere, and heterogeneous catalyst in tar elimination during the biomass thermochemical conversion process. However, there are some problems, like the economical catalyst chosen for the industrial development of gasification, and integration difficulties between gasification and downstream technologies are still not well discussed. Hence, in this review, we first assess the recent advancements in catalyst fabrication and the activity performance in reforming biomass tar and tar model compounds. After that, the clean-up of produced gas for the next-step application is reviewed. Importantly, we discuss the composition of the produced gas, the possibilities and challenges of the integration with the production of methane, methanol, ethanol, and C 2+ alcohols. Finally, the conclusion and prospective are concluded to give an outlook for the development of catalyst, biomass tar reforming, and integration with downstream technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical Ga/Al HZSM-5 exhibits high BTEXN yield at 600 °C. • Ga and HZSM-5 presented a strong synergy during the formation of aromatics. • Ga/Al HZSM-5 keep high stability during 6th cycle reactions. • Multifunctional catalysts promote the formation of H 2 by dehydrogenation. HZSM-5 was hydrothermally synthesized by Ga substitution to regulate the texture properties for light aromatics such as benzene, toluene, ethylbenzene, xylenes and naphthalene (BTEXN) during the lignite volatiles catalytic upgrading process. High BTEXN yield was obtained over xGa/H5(A) (added NaOH in crystallization) and the value increased with raising the amount of Ga incorporation when the Ga content was<1.26 g. 1.26 Ga/H5(A) (1.26 g Ga(NO 3) 3) displayed the highest yield of BTEXN (29.3 mg/g-daf coal) since Ga species and acidic protons promoted the aromatization process. However, excessive Ga brought a negative effect on the production of aromatics due to the weakened synergistic effect between Ga species and acid sites of H5. Additionally, 1.26 Ga/H5(A) with the interconnected meso -micropores and moderate acidity distribution exhibited excellent reaction stability during the 6 cycle experiments. xGa/H5(A) provided a potential prospect for enhancing the BTEXN formation during catalytic upgrading of lignite pyrolysis volatiles. [ABSTRACT FROM AUTHOR]

A novel type of oxygen-enriched three-dimensional porous carbons (3DPCs) is prepared using coal tar pitch (CTP) oxidized by KMnO 4 as raw material and NaCl as a green template. Oxygen-containing functional groups are grafted on the edge of polycyclic aromatic hydrocarbons (PAHs) through oxidative modification, which avoids excessive accumulation of PAHs and successfully achieves oxygen doping to provide additional pseudo-capacitance. The existence of NaCl supports the formation of 3D structure and improves the diffusion/transport capacity of electrolyte ions. The as-prepared 3DPCs show interconnected 3D structure with large effective specific surface area (3067 m2 g−1) and high oxygen content (up to 9.8%). In addition, the electric double layer capacitor assembled by 3DPC-3 exhibits the largest specific capacitance (306 F g−1 at 0.5 A g−1) and superior cycling stability (specific capacitance retention of 99.7% after 10000 cycles) in 6 M KOH electrolyte. Meanwhile, high energy density (36.8 Wh kg−1) is obtained when it is applied to EMIMBF 4 electrolyte. Overall, this work provides an effective way for the synthesis of 3DPCs and can be also conducive to the development of the high value-added CTP-based carbon material industry. • Coal tar pitch was oxidized by KMnO 4. • Oxygen-enriched three-dimensional porous carbons was prepared. • Outstanding cycling performance up to 99.7% after 10000 cycles. • High energy density (36.8 Wh kg−1) in EMIMBF 4 electrolyte. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metallic Co highly dispersed on char using lignite as carbon precursor. • The Co nanoparticles loaded by ion exchange method are smaller than Ni. • The interaction between Co and lignite is stronger than Ni. • Co/modified lignite char efficiently catalyzes tar cracking at low temperature. • The oxygen affinity of Co is key to carbon-deposition resistant. The development of cheap and highly dispersed nano-catalyst is one of the key technologies for low temperature steam reforming (SR) of biomass tar. This work used acid-washed and oxidized Shengli lignite char (OXAWSL) as carbon precursor to load Co (Co/OXAWSL) and Ni (Ni/OXAWSL) via ion exchange method to SR of toluene and biomass tar. The Co/OXAWSL was more active and stable than Ni/OXAWSL during the 30 h test with a final toluene conversion of 85% at a relatively low temperature of 450 °C and steam to carbon ratio (S/C) of 3.4, which resulted from its small particle size (5.6 nm) and high dispersion (12.3%) of Co. The relatively high H 2 production (42.59 mmol/g-biomass) over Co 0.1 /OXAWSL (450 °C, S/C = 3.4) in SR of tar was also obtained. A low E a (22.0 kJ/mol) value of Co/OXAWSL and good affinity to oxygen for Co explained its excellent performance. The low-temperature tar cracking process can provide theoretical and technical support for the large-scale industrial utilization of biomass pyrolysis and gasification. [ABSTRACT FROM AUTHOR]

Ni-encapsulated (Ni@HZ5) and Ni-incorporated (x Ni/HZ5) zeolites were prepared via one-pot hydrothermal synthesis and impregnation method, respectively, and further employed for hydroconversion of pyrolytic volatiles of spent coffee grounds into benzene, toluene, ethylbenzene, xylene, naphthalene (BTEXN) in a drop tube reactor under H 2 atmosphere. The properties of metallic Ni species on Ni@HZ5, x Ni/HZ5 and Ni/Al 2 O 3 were comparably characterized. Ni@HZ5 displayed superior selectivity for BTEXN production among those catalysts, especially for B and T. Metallic Ni species encapsulated MFI-type framework plays crucial roles in enhancing aromatics selectivity, promoting oligomerization, cyclization and aromatization of small molecular hydrocarbons in channels. On the contrary, Ni species presented on the external zeolite surface is in favor of hydrocracking and hydrogenolysis of macromolecular pyrolytic fragments. It also exhibited high coke content containing "soft" and "hard" coke, which was mainly caused by metallic particles sintering. An important difference was proposed in the effect of Ni species on reaction pathway for catalytic upgrading of volatiles to BTEXN. The configured Ni@HZ5 inhibits sintering and has potential of enhancing BTEXN by catalytic hydropyrolysis of biomass. [Display omitted] • Ni-encapsulated zeolite was synthesized by organic ligands assisting. • Ni-encapsulated zeolite enhanced light aromatics formation remarkably. • The catalytic performance of metal active sites is dependent of metallic location. • Ni species embedded in HZSM-5 can inhibit metallic sintering. [ABSTRACT FROM AUTHOR]

• Ga-Sn/AT 0.2 H5 exhibits hierarchical meso-microporesity to rich BTEXN at 600 °C. • Ga and Sn exhibited a strong synergy during the formation of aromatics. • Ga-Sn/AT 0.2 H5 keep high stability after 6 cycle reactions. • Multifunctional catalysts promote the formation of H 2 by dehydrogenation. A multifunctional catalyst of Ga-Sn anchored on hierarchical HZSM‑5 (Sn-Ga/AT 0.2 H5) was investigated in catalytic reforming of lignite pyrolysis volatile. A strong synergy was observed between Ga and Sn for the production of aromatics. The addition of Ga into AT 0.2 H5 remarkably promoted the selectivity of aromatics including benzene, toluene, ethylbenzene, xylene and naphthalene (BTEXN) compared to pure HZSM-5 (H5). The BTEXN yields increased to 24.1 mg/g over monometallic 5%Ga/AT 0.2 H5, in which the benzene yield was attained to 14.8 mg/g. With the introduction of Sn, the yield of aromatics was further improved to 25.1 mg/g. An explanation of this scenario was that introduced active metals could enhance the transformation of cyclic intermediates into aromatics and H5 support with an appropriate concentration of the acid sites provided acidic protons for aromatization. Additionally, the bimetallic Sn-Ga/AT 0.2 H5 exhibited higher stability with the yield of BTEXN maintained over 22 mg/g after three recycle experiments, which offered an efficient strategy to prolong the catalyst lifetime. [ABSTRACT FROM AUTHOR]