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Catalytic conversion of glucose to 5-hydroxymethylfurfural (HMF) is a highly desirable routine for producing value-added chemicals. Herein, by using glucose as carbon source to fabricate porous carbon support, SnCl 4 and citric acid were selected for forming Lewis acidic/ basic SnO x and Brønsted −COOH over support, respectively, bifunctional solid acid tin oxide/ carbon catalysts were prepared by a hydrothermal-pyrolysis strategy. It is found that the acid density of SnO x /C could be tuned by adjusting SnCl 4 dosage and pyrolysis temperature. In a H 2 O-NaCl/THF biphasic system, 92.1% glucose conversion and 84.1% HMF yield were achieved over an optimized 3.0-SnO x /C-500 catalyst at 180 °C for 2 h. This catalyst demonstrates excellent recyclability in this reaction for five times and is also versatile for one-pot transformation of cellulose to HMF with 39.9% yield. The superior performance of 3.0-SnO x /C-500 could be ascribed to its highly dispersed SnO x nanoparticles, a suitable ratio of Brønsted to Lewis acids, as well as accessible pore-structure of the catalyst.

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Lithium-ion capacitors (LICs) are considered to be one of the most promising energy storage devices which have the potential of integrating high energy of lithium-ion batteries and high power and long cycling life of supercapacitors into one system. However, the current LICs could only provide high power density at the cost of low energy density due to the sluggish Li+ diffusion and/or low electrical conductivity of the anode materials. Moreover, the serious capacity and kinetics imbalances between anode and cathode result in not only inferior rate performance but also unsatisfactory cycling stability. Therefore, designing high-power and structure stable anode materials is of great significance for practical LICs. Under this circumstance, graphene-based materials have been intensively explored as anodes in LICs due to their unique structure and outstanding electrochemical properties and attractive achievements have been made. In this review, the recent progresses of graphene-based anode materials for LICs are systematically summarized. Their synthesis procedure, structure and electrochemical performance are discussed with a special focus on the role of graphene. Finally, the outlook and remaining challenges are presented with some constructive guidelines for future research.

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