Single-step production of hydrogen-rich syngas from toluene using multifunctional Ni-dolomite catalysts

Abstract Tar compounds such as toluene can be oxidatively converted by reforming, followed by water–gas-shift and CO2 removal to produce H2-rich syngas. We report a type of low-cost multifunctional catalysts that are capable of producing hydrogen-rich syngas from toluene in a single reactor. The multifunctional catalysts, derived from Ni-loaded dolomite, also act as oxygen carriers and CO2 sorbents. When operating under a chemical looping-type scheme at 700 °C, the catalyst containing 15 wt% NiO could produce syngas containing >70% hydrogen, with a cold-gas-efficiency of 90.3%. No sign of deactivation, coking or structural change was observed over 10 consecutive cycles of reforming and regeneration. The remarkable performance is attributed to the promotional effects arising from the formation of the MgxNi1-xO solid solution. Additionally, MgO acts as a support and provides sintering resistance to both the Ni catalyst and the CaO-based CO2 sorbent, making the multifunctional structure highly regenerable over cyclic operation.