Preparation of La2O3/ZnO dodecahedral nanopowders induced by ZIF-8 via an innovative mild aqueous solvent approach and evaluation of their gas-sensitive properties towards H2S

Investigating high-performance and low-energy consumption H 2 S sensors has become a hot research topic. This study adopted a one-step co-precipitation method to synthesize La-doped ZIF-8 deprotonating zinc acetate, lanthanum nitrate, and 2-Methylimidazole in an aqueous. La 2 O 3 /ZnO were synthesized with different La 3+ doping concentrations (0, 0.5, 1, and 1.5 at%). We found that La 3+ doping at a concentration of 1 at% showed the highest response value of 140 for 5 ppm H 2 S, at a low operating temperature of 100 °C, which is 2.4 times higher than that of pure ZnO. Additionally, La 3+ doping led to a lower detection limit of 1.9 ppb. The enhanced performance can be attributed to the widening of the difference in electron concentration, the increase in vacant oxygen content, and the spillover effect of H 2 S sensing. These factors were analyzed in detail by means of porosity, P-N heterojunctions, and the increased in adsorbed oxygen content caused by La 3+ doping.