Leaf-templated synthesis of 3D hierarchical porous cobalt oxide nanostructure as direct electrochemical biosensing interface with enhanced electrocatalysis

A novel three-dimensional (3D) hierarchical porous cobalt oxide (Co3O4) architecture was first synthesized through a simple, cost-effective and environmentally friendly leaf-templated strategy. The Co3O4 nanoparticles (30-100 nm) with irregular shapes were interconnected with each other to form a 3D multilayer porous network structure, which provided high specific surface area and numerous electrocatalytic active sites. Subsequently, Co3O4 was successfully utilized as direct electrochemical sensing interface for non-enzymatic detection of H2O2 and glucose. By using chronoamperometry, the current response of the sensor at +0.31 V was linear with H2O2 concentration within 0.4-200 mu M with a low limit of detection (LOD) of 0.24 mu M (S/N=3) and a high sensitivity of 389.7 mu A mM(-1) cm(-2). Two linear ranges of 1-300 mu M (with LOD of 0.1 mu M and sensitivity of 471.5 mu A mM(-1) cm(-2)) and 4-12.5 mM were found at +0.59 V for glucose. In addition, the as-prepared sensor showed excellent stability and anti-interference performance for possible interferents such as ascorbic acid, uric acid, dopamine, acetaminophen and especially 0.15 M chloride ions. Similarly, other various metal oxide nanostructures may be also prepared using this similar strategy for possible applications in catalysis, electrochemical sensors, and fuel cells. (C) 2014 Elsevier B.V. All rights reserved.