Catalytic production of H2-rich syngas from cellulose pyrolysis under nickel metal fog with molten carbonates

The Ni was dissolved as metal fog for homogeneous catalytic pyrolysis cellulose to produce H 2 -rich syngas in the molten carbonates. The Ni atoms firstly contact with CO 3 2− to form NiCO 3 in molten carbonate, then quickly decomposes into nickel oxide . The undissolved Ni atoms agglomerate with nickel oxide and remained nickel carbonate to synthesize metal cluster. The XRD and ex-situ Raman spectroscopy indicate that the oxidation state of the catalyst is between 0 (Ni sample) and +2 (NiO sample), meanwhile the TEM proposed that smaller particle size (50 nm) and higher dispersion of catalyst compared with raw Ni powder. Ni metal fog formed are expected to maximizing the production of H 2 -rich syngas by catalyzing cleavage of C–C and C–H bonds, which further contributes to tar cracking and water-gas shift reaction. The molten carbonate together with Ni metal fog pyrolysis cellulose achieved the maximum hydrogen yield of 289.16 ml/g-cellulose at 575 °C. A recycling study indicated that the hydrogen generated after five recycling cycles of the system was still maintained 289.05 ml/g-cellulose.