Acid pretreatment of lignocellulosic biomass, required for bioethanol production, generates large amounts of by-products, such as lignin and hydrolyzed hemicellulose fractions, which have found so far very limited applications. In this work, we demonstrate how the recovered hemicellulose hydrolysis products can be effectively utilized as a precursor for the synthesis of functional carbon materials through hydrothermal carbonization (HTC). The morphology and chemical structure of the synthesized HTC carbons are thoroughly characterized to highlight their similarities with glucose-derived HTC carbons. Furthermore, two routes for introducing porosity within the HTC carbon structure are presented: i) silica nanoparticle hard-templating, which is shown to be a viable method for the synthesis of carbonaceous hollow spheres; and ii) KOH chemical activation. The synthesized activated carbons (ACs) show an extremely high porosity (pore volume≈1.0 cm(3) g(-1)) mostly composed of micropores (90 % of total pore volume). Because of their favorable textural properties, the ACs are further tested as electrodes for supercapacitors, yielding very promising results (300 F g(-1) at 250 mA g(-1)) and confirming the high suitability of KOH-activated HTC carbons derived from spruce and corncob hydrolysis products as materials for electric double layer supercapacitors.

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The preparation of nitrogenated carbon nanotubes (N-CNT) using pyridine as a carbon precursor resulted in an eight-times increase in gravimetric capacitance.

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Different Pt-and Ru-doped Ti/SnO 2 −Sb electrodes were synthe-

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This work focuses on the preparation of flexible ruthenium oxide containing activated carbon cloth by electrodeposition. Different electrodeposition methods have been used, including chronoamperometry, chronopotentiometry and cyclic voltammetry. The electrochemical properties of the obtained materials have been measured. The results show that the potentiostatic method allows preparing composites with higher specific capacitance than the pristine activated carbon cloth. The capacitance values measured by cyclic voltammetry at 10 mV s -1 and 1 V of potential window were up to 160 and 180 F g -1 . This means an improvement of 82 % and 100 % with respect to the capacitance of the pristine activated carbon cloth. This excellent capacitance enhancement is attributed to the small particle size (4-5 nm) and the three-dimensional nanoporous network of the ruthenium oxide film which allows reaching very high degree of oxide utilization without blocking the pore structure of the activated carbon cloth. In addition, the electrodes maintain the mechanical properties of the carbon cloth and can be useful for flexible devices.Corresponding Author *E. Morallon, morallon@ua.es, Telf. +34-965909590 2 IntroductionThe rapid population growth, economic expansion and industries development has increased the global energy consumption. Today, fossil fuels (oil, gas and coal) supply around 85 % of the energy market, providing more than 80 % of the carbon dioxide anthropogenic emissions released into the atmosphere each year. As a result, the present energy system could not be able to sustain the global economic growth in a relative short period of time [1]. In this scenario, the government´s efforts are focused on the development of sustainable solutions that include the replacement of fossil fuels by renewable energy sources, efficiency improvements in the energy production and energy savings on the demand side in order to reduce the carbon emission and to mitigate the global warming consequences (i.e., global climate change and level sea rise) [2].However, many of the renewable energy sources are of a fluctuating nature and cannot cover the daily electricity consumption of industries, households/services and transport activities [3]. To solve this limitation, an efficient storage device can be employed in order to cover the power consumption during the low/zero period of energy production or during a peak power demand [4,5].One of the most important challenges facing scientists today is the construction of efficient systems that can store the energy produced by renewable sources and make it available according to the demand. In this respect, supercapacitors have attracted great attention because they can be used for large commercial applications ranging from small electronic devices as cell phones and emergency medical equipment to electric vehicles and photovoltaic cells [6]. For instance, supercapacitors can be used to recuperate the breaking energy in electric buses [7] and electric/fuel cell cars [8] or to storage the exc...