With the assistance of plant extracts, the facile synthesis of three-dimensional (3D) porous LaCoO3 perovskite is reported at a lower calcination temperature of 500 degrees C. The formation mechanism is carefully studied by investigating the different roles of organic and inorganic components in Cacumenplatycladi extract. The results indicate that organic components (mainly phenolic acids) function as the similar complex species of citric acid, while the mineral nutrients (Na+, K+, Ca2+, and Mg2+) together with NO3- serve as combustion-aid agents even with trace amounts. Moreover, the biosynthesized LaCoO3 has a high surface area of 32.5 m(2) g(-1) and exhibits excellent catalytic performance for benzene oxidation. Benzene of 1000 ppm can achieve a stable conversion above 90% at 285 degrees C in a continuous run for 80 h (weight-hourly space velocity (WHSV) = 40 000 mL g(-1) h(-1)). It can be attributed to the bio-LaCoO3 with more electrophilic adsorption of oxygen species and 3D porous structure.