Noble-metal-free bimetallic alloy nanoparticle-catalytic gasification of phenol in supercritical water

- Noble-metal-free bimetallic nanoparticle catalysts were prepared and used for SCWG.
- A nearly complete gasification of phenol was achieved at 450 °C.
- NiZn catalyst favored the production of CH4 while NiCo favored the H2 production.
- The stability of the bimetallic nanoparticle catalysts was investigated.

The exploration of non-noble-metal catalysts for high efficiency gasification of biomass in supercritical water (SCW) is of great significance for the sustainable development. A series of Ni-M (M = Co or Zn) bimetallic nanoparticles supported on graphitized carbon black were synthesized and examined as catalysts for gasification of phenol in SCW. It was found that a nearly complete gasification of phenol can be achieved even at a low temperature of 450 °C with the bimetallic nanoparticles catalysts. Kinetic study indicated the activation energy for phenol gasification were 20.4 ± 2.6 and 43.6 ± 2.6 kJ/mol for Ni20Zn15 and Ni20Co15 catalyst, respectively. XRD, XPS and TEM were further performed to characterize the catalysts and the results showed the formation of NiCo and NiZn alloy phase. Catalyst recycling experiments were also conducted to evaluate the stability of the catalysts. The characterization of used catalysts suggest that the severe agglomeration of nanoparticles leads to the decrease in catalytic activity.

The nonprecious bimetallic nanoparticles (Ni cooperated in Co or Zn) exhibit excellent catalytic performance for gasification of phenol. It was found that a nearly complete gasification of phenol can be achieved even at a low temperature of 450 °C.136