Sodium alginate assisted preparation of oxygen-doped microporous carbons with enhanced electrochemical energy storage and hydrogen uptake

Abstract Microporous carbons with large oxygen content have been successful synthesized from biomass by the sodium alginate assisted strategy. During the activation process, the Na2O formed by the decomposition of sodium alginate combines with the activator KOH to undergo a redox reaction in situ with precursor, thereby forming a rich porosity in the samples. The obtained samples possess not only high SSA (2310~3001 m2 g−1) and large pore volume (0.89~1.19 cm3 g−1) arising almost completely (>90%) from micropores, but also retains a high content of oxygen (21.86~32.47 wt %). As supercapacitor electrodes, the oxygen-doped microporous carbons display a high specific capacitance of 385 F g−1 at 0.5 A g−1 with capacity stability of 91.5% after 20 000 cycles at 5 A g−1. As hydrogen storage materials, the oxygen-doped microporous carbons exhibit enhanced hydrogen storage capacity of 2.84 wt% (77 K, 1 bar) and 0.91 wt% (303 K, 50 bar). Experimental data indicate that this work provides a simple-efficient and universal strategy for preparing oxygen-doped microporous carbon for high-performance energy and hydrogen storage.