We report one-step conversion of dimensionally mixed ternary nanocomposite from zerodimensional (0D) cerium oxide (CeO 2 ), one-dimensional (1D) carbon nanotube (CNT), and two-dimensional (2D) reduced graphene oxide (RGO) nanomaterials by chemical precipitation method. The RGO/CNT/CeO 2 ternary nanocomposite showed excellent electrochemical performance (electrical double layer capacitor properties) in aqueous electrolyte followed by long term cyclic stability, and high energy density compared to its binary counterparts.

Nanoporous activated carbons (AC) have been prepared from low-cost agro-waste corncob powder by phosphoric acid activation and investigated for their electrochemical supercapacitor and sensing properties. Surface areas and pore volumes are found in the range of 690–1288 m2 g−1 and 0.49–1.64 cm3 g−1, respectively and could be controlled by adjusting the weight ratio of corncob and phosphorous. The corncob-derived AC showed excellent electrochemical performance giving a maximum specific capacitance ca. 340.8 F g−1 at a scan rate of 5 mV s−1. At relatively a high scan rate of 100 mV s−1 the specific capacitance of 133.7 F g−1 was obtained. About 96% capacitance retention rate was achieved even after 1000 cycles demonstrating potential usages of the materials in high-performance supercapacitor electrodes. Furthermore, our AC showed excellent solvent vapor sensing performance with high selectivity for ammonia.

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