Porous silicon oxycarbide derived carbon (SiOC-DC) materials are receiving an increasing interest during the last decades for their potential use in the field of “green” energy to be used as gas storage/capture materials (H₂, CO₂, CH₄, etc.), electrodes for metal-ion batteries (Li, Na, etc.) and supercapacitors among others. In order to achieve a good electrochemical response the electrodes for supercapacitors should have a high electronic conductivity and an adequate pore size distribution comprising micro-meso and also macropores.^1,2,3 SiOC materials are composed by a mixed network of Si-O-C bonds and a C-free phase homogenously embedded within the matrix. SiOC materials usually display a relatively low electrical conductivity which can be raised increasing the amount of carbon and/or the pyrolysis temperature of the initial SiOC material. In addition, there are several methods to produce highly porous SiOC-DC by the selective removal of SiO₂/SiC phases.⁴ In this work, we have employed Cl₂ etching, which has been extensively used in carbide materials to give microporous materials with extremely high specific surface area (SSA). In addition, depending on etching conditions and the carbide precursors the pore size can be tuned. Cl₂ etching of SiOC produces micropores and mesopores from the removal of SiC and Si-O-C mixed network, repectively.⁵ In this study, we have prepared C-enriched SiOC materials from sol-gel derived triethoxysilane/dimethyldiphenilsiloxane (TREOS/DMDPS) hybrids pyrolyzed at different temperatures (from 1100 to 1400 °C). The SiOC materials have been Cl₂ etched at 800 °C to ensure the maximum amount of carbon in the final SiOC-DC material. The influence of the pyrolysis temperature, scarcely studied in the literature, has been determined in terms of phase separation, the subsequent removal of SiO₂/SiC and so the type of porosity formed in conjunction with their electrochemical response. The electrochemical measurements have been carried out in a two electrode configuration set up employing 1M H₂SO₄ as electrolyte. The SiOC-DC pyrolyzed at 1100 °C displays a SSA of 2500 m²g^-1 with the presence of micro, meso and macropores. The hierarchical microstructure renders in a high electrochemical capacity response of 200-125 Fg^-1 at low (0.35 Ag^-1) and a high (50 Ag^-1) current density, respectively. Cycling stability studies up to 10000 cycles were also performed showing an excellent behaviour.
 
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