화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.42, No.10, 6511-6518, 2017
High performance noble-metal-free NiCo/AC bimetal for gasification in supercritical water
We report high performance Noble-metal-free NiCo/AC bimetal for gasification in super-critical water by the polyol reduction method with chloroplatinic acid as nucleation seed. At 475 degrees C and 20 min, the carbon efficiency (CE) for gasification of phenol with NiCo/AC has reached about 65%, which represents a more than 20-fold enhancement of carbon efficiency compared to the Co/AC and 6-fold compared to the Ni/AC. The CE of commercial noble Ru/C (5 wt%) catalyst is only about 15% higher than that of NiCo/AC catalyst. The catalyst was characterized by BET, XRD, XPS and TEM. The results indicate smaller and higher disperse of NiCo alloy has been achieved. By using NiCo/AC catalyst, the CE can reach about 90% at 525 degrees C and 60 min with a 5 wt% phenol, 0.098 kg/m(3) density and catalyst loading of 0.5 g/g (the mass of NiCo/AC catalyst/the mass of phenol). The results of GC MS indicate NiCo/AC can suppress tar successfully. A kinetic modeling was also proposed to describe gaseous product and tar formation, which gives the activation energy (Ea) 123.56 +/- 31 kJ/mol and the frequency factor 16.93 +/- 0.48 for gaseous products. While for tar formation, the Ea is 112.95 +/- 24 kJ/mol and the frequency factor is 13.99 +/- 0.37. The successful use of noble-metal-free NiCo/AC shows the potential to replace noble Ru-catalysts in SCWG process for gases fuels by bimetal. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.