NiCo@NiCo phyllosilicate@CeO2 hollow core shell catalysts for steam reforming of toluene as biomass tar model compound

Highlights: • NiCo@NiCo phyllosilicate@CeO₂ core shell hollow spheres have been designed. • They exhibit active and stable performance of 45 h TOS for STR reaction. • High metal sintering resistance and oxygen vacancies alleviate the carbon deposition. • Synergistic effect between Ni and Co further improves their carbon resistance. • They show promising application in tar steaming reforming reaction. -- Abstract: Developing sintering and carbon resistant tar removal catalysts is crucial for biomass gasification technology. Herein, for the first time, NiCo@NiCo phyllosilicate@CeO₂ hollow core shell catalysts have been designed for steam reforming of toluene (SRT) as the biomass tar model compound. They show both good catalytic activity and stability within 45 h of time on stream due to their high sintering resistance of NiCo because of the strong interactions between NiCo and CeO₂, high metal exposure as a result of the high specific surface area, high surface metal concentration as well as the high oxygen vacancies as evidenced from the H₂-Temperature-programmed reduction (H₂-TPR), H₂ chemisorption and X-ray photoelectron spectroscopy (XPS) characterizations respectively. Additionally, the synergistic effect between Ni and Co further improves their carbon resistant property. By comparison, Co@Co phyllosilicate@CeO₂ catalysts perform the lowest toluene conversion and stability mainly due to their structural instability during reaction resulting from their high Si/Co ratio, leading to their low specific surface area and Co exposure. The outstanding SRT performance of NiCo@NiCo phyllosilicate@CeO₂ catalysts indicates their promising application for steam reforming of biomass tar reaction.