Self‐Template Synthesis of Mesoporous Metal Oxide Spheres with Metal‐Mediated Inner Architectures and Superior Sensing Performance

Abstract The development of a general strategy to synthesize mesoporous metal oxide spheres (MMOSs) with tailorable compositions and architectures is desirable and challenging. Herein, a general self‐template strategy is demonstrated for the synthesis of MMOSs with tunable compositions (i.e., ZnO, Al 2 O 3 , Co 3 O 4 , Fe 2 O 3 , CuO) and metal‐mediated inner architectures via thermal decomposition of metal‐phenolic coordination polymers (MPCPs). The metal species in MPCPs can obviously influence the decomposition temperature of the polymer networks ( T d ). The inner architectures of MMOSs are determined by T d and the crystallization temperature of metal oxides ( T c ). The MMOSs show solid inner architectures when T d > T c or T d < T c and hollow structure when T d ≈ T c . Encouraged by their high surface area and accessible mesopores, gas sensors based on MMOSs (i.e., ZnO) are fabricated, which shows a low working temperature (250 °C) for detection of ethanol gas. The MMOSs (i.e., Co 3 O 4 ) can further be used to fabricate sensing platform for detecting DNA analogue of miRNA‐21 (a biomarker abnormally expressed in most of solid tumors). Such MMOSs show high sensitivity (0.19 × 10 −9 m ) and can even efficiently distinguish the target DNA from single‐, double‐ and triple‐base mismatched DNA.