Abstract
Porous carbon particles (PCPs) prepared from sucrose via the hydrothermal method and its modified forms with polyethyleneimine (PEI) as PCP-PEI were used as templates as in situ metal nanoparticles as M@PCP and M@PCP-PEI (M:Co, Ni, or Cu), respectively. The prepared M@PCP and M@PCP-PEI composites were used as catalysts in the hydrolysis of NaBH4 and NH3BH3 to produce hydrogen (H2). The amount of Co nanoparticles within the Co@PCP-PEI structure was steadily increased via multiple loading/reducing cycles, e.g., from 29.8 +/- 1.1 mg/g at the first loading/reducing cycles to 44.3 +/- 4.9 mg/g after the third loading/reducing cycles. The Co@PCP-PEI catalyzed the hydrolysis of NaBH4 within 120 min with 251 +/- 1 mL H2 production and a 100% conversion ratio with a 3.8 +/- 0.3 mol H2/(mmol cat<middle dot>min) turn-over frequency (TOF) and a lower activation energy (Ea), 29.3 kJ/mol. In addition, the Co@PCP-PEI-catalyzed hydrolysis of NH3BH3 was completed in 28 min with 181 +/- 1 mL H2 production at 100% conversion with a 4.8 +/- 0.3 mol H2/(mmol cat<middle dot>min) TOF value and an Ea value of 32.5 kJ/mol. Moreover, Co@PCP-PEI composite catalysts were afforded 100% activity up to 7 and 5 consecutive uses in NaBH4 and NH3B3 hydrolysis reactions, respectively, with all displaying 100% conversions for both hydrolysis reactions in the 10 successive uses of the catalyst.
