Developing Ni/SAPO-11 deoxygenation catalysts using yttrium modified SAPO-11 prepared by rice husk ash

•Stable SAPO-11 molecular sieves are prepared using rice husk ash modified by yttrium.•Role of yttrium in improving the dispersion of Ni0 sites is elucidated.•Deactivation mechanism of Ni/SAPO-Y catalysts in catalyst cycle experiment is proposed. To suppress the aggregation of metallic sites, a novel Ni/SAPO-Y deoxygenation catalyst is developed using yttrium modified SAPO-11 prepared by rice husk ash (RHA). Yttrium oxide interacts with silicon atoms to form Si-O-Y bonds, which enhance the bond strength of Si-O bonds and function as space barriers to inhibit the aggregation of Ni0 sites. In the catalytic evaluation, Ni/SAPO-Y exhibits a higher conversion due to an excellent dispersion of Ni0 sites. It is favorable for the decarboxylation and/ or decarbonylation of stearic acids on fine Ni0 particles with a low consumption of H2. In the catalyst cycle experiments, aggregation of Ni0 sites results in the deactivation of regenerated catalysts due to the removal of aluminium hydroxyl groups and decrease of BET surface area. A high acid retention of regenerated catalysts provide excellent isomerization activity (i.e., a yield for iso-paraffin (8.5-10.5%)). Besides the excellent performance of developed Ni/SAPO-Y catalysts, the current research proposes a disposal method for the agricultural waste rice husk.