One-Pot Catalytic Conversion of Xylose to Furfural on Mesoporous Niobium Phosphate

A series of advanced progress has been made toward flexible supercapacitor design in recent years, including micro-SCs based on serpentine interconnections, [8] fiber-shaped SCs, [9] and the devices based on new crumpled-graphene papers, [10] tricot weave, [11] hierarchically buckled sheah-core fibers. [12] Nevertheless, the practical application of WSSPs is still limited by their low energy density. [13] According to the equation of energy density E = 1/2 C V 2 , for a given supercapacitor (SC), the energy density highly depends on the specific capacitance (C) and operating voltage window (V). [13] Given by this equation, the energy density is proportional to the square of operating voltage window. In general, the electrochemical stability window of most energystorage materials is less than 0.8 V in aqueous electrolytes due to the water splitting at 1.23 V, and high-voltage materials is highly desired to enhance the energy density. [14] Most recently, layered polyanionic phosphates, such as VOPO 4 , Na 3 V 2 (PO 4 ) 3 , NaVOPO 4 , KVPO 4 F, and KVOPO 4 , have been considered as promising electrode materials for energy storage because of their high thermal and structural stability. [15] More importantly, it has been theoretically predicted a much higher potential (≈1.0 V in aqueous electrolyte) in layered phosphates than in most of the traditional pseudocapacitive materials due to the enhanced iconicity of metaloxygen bond with the existence of [PO 4 ] 3− group. [16][17][18][19] Meanwhile, niobium (Nb) is an important transition metal element with rich oxidation states (Nb 3+ , Nb 4+ , and Nb 5+ ) for potential electrochemical energy storage. A unique Li + -intercalation pseudocapacitance has been found in T-Nb 2 O 5 (40 µm thick) electrode, which holds a great perspective on the development of electrochemical electrodes. [20,21] Especially, the pseudocapacitance occurs in the T-Nb 2 O 5 bulk rather than the surface or near-surface of the electrode, resulting high specific capacitances and energy density. [20] These interesting results inspire us to consider whether Nb atoms could be intercalated into the layered polyanionic phosphate to form layered niobium phosphate as high-performance electrode materials for WSSPs.

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Conversion of raw lignocellulosic biomass into branched long‐chain alkanes through three tandem steps

Ding

Xia

et al. 2016

ChemSusChem

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Synthesis of branched long-chain alkanes from renewable biomass has attracted intensive interest in recent years, but the feedstock for this synthesis is restricted to platform chemicals. Here, we develop an effective and energy-efficient process to convert raw lignocellulosic biomass (e.g., corncob) into branched diesel-range alkanes through three tandem steps for the first time. Furfural and isopropyl levulinate (LA ester) were prepared from hemicellulose and cellulose fractions of corncob in toluene/water biphasic system with added isopropanol, which was followed by double aldol condensation of furfural with LA ester into C15 oxygenates and the final hydrodeoxygenation of C15 oxygenates into branched long-chain alkanes. The core point of this tandem process is the addition of isopropanol in the first step, which enables the spontaneous transfer of levulinic acid (LA) into the toluene phase in the form of LA ester through esterification, resulting in LA ester co-existing with furfural in the same phase, which is the basis for double aldol condensation in the toluene phase. Moreover, the acidic aqueous phase and toluene can be reused and the residues, including lignin and humins in aqueous phase, can be separated and carbonized to porous carbon materials.

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One-Pot Catalytic Conversion of Xylose to Furfural on Mesoporous Niobium Phosphate

Cited by 12 publications

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Niobium‐Based Catalysts for Biomass Conversion

Niobium‐Based Catalysts for Biomass Conversion

Novel Sub‐5 nm Layered Niobium Phosphate Nanosheets for High‐Voltage, Cation‐Intercalation Typed Electrochemical Energy Storage in Wearable Pseudocapacitors

Conversion of raw lignocellulosic biomass into branched long‐chain alkanes through three tandem steps

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