| Content of Co species in Co2p (At%) | ||||
| Samples | Co2p1/2 | Co2p3/2 | ||
| Co2+ | Co3+ | Co2+ | Co3+ | |
| BS-Co3O4 | 44.61% | 32.56% | 12.31% | 10.52% |
| Co3O4 | 25.49% | 47.93% | 15.49% | 11.15% |