Surface oxygen vacancy adjustment and acetone sensing performance enhancement of ZIF-67 derived Co3O4 with trace Ni-doping

The adjustment of surface oxygen vacancy was realized by doping the trace Ni element into the lattice of ZIF-67 derived Co3O4. The material characterizations indicated that ZIF-67 derived Co3O4 samples have porous square structure and the trace Ni elements successfully enter the lattice of Co3O4 crystal. Because of the increased oxygen vacancies caused by Ni-doping, the content of oxygen species chemically adsorbed on the surface of the optimized sample increased by 12.14 %. Compare with the pure Co3O4, the optimum operating temperatures of all the samples with trace Ni-doping were reduced by 20 °C. The response to 50 ppm acetone of the optimized sample was 30.02 with good selectivity and stability, and the response was 1.67 times higher than that of the pure one. The response-recovery rate was also improved. The response and recovery time of the optimized sample were 38 s and 35 s less than that of the pure one. The influences of oxygen vacancy and Co2+ were analyzed to understand the mechanism of the enhanced sensing properties.