Chemical looping hydrogen generation (CLHG), as a new technology involved in chemical looping combustion (CLC) process and steam-iron process, has attracted attention for clean energy generation and efficient energy conversion. A systematic investigation of spinel NiFeAlO4 has led to characterization of a well-defined self-supported oxygen carrier which was prepared by solid state reaction. The redox behavior of NiFeAlO4 shows the enhancement on the resistance to agglomeration exceeding previously reported CLC process using similar compositions including Fe2O3, NiO and NiFe2O4 without any inert support. Moreover, the high CO2 conversion and H2 generation by NiFeAlO4 oxygen carrier under a fixed-bed reactor (FxBR) were obtained. The reaction mechanism of NiFeAlO4 subjected to the isothermal stepwise reduction in a sequence of varying durations by XRD was also demonstrated, which provided with a novel function of self-supported and agglomeration-resistant characteristic in the oxygen carrier system.