Direct Electrodeposition of Bimetallic Nanostructures on Co-Based MOFs for Electrochemical Sensing of Hydrogen Peroxide.

Hydrogen peroxide (HO) is the most significant reactive oxygen species in biological systems. Here, we reported an electrochemical sensor for the detection of HO on the basis of bimetallic gold-platinum nanoparticles (AuPt NPs) supported by Co-based metal organic frameworks (Co-MOFs). First, AuPt NPs, with optimal electrocatalytic activity and accessible active surface, can be deposited on the surface of the Co-MOF-modified glassy carbon electrodes (AuPt/Co-MOFs/GCE) by one-step electrodeposition method. Then, the electrochemical results demonstrated that the two-dimensional (2D) Co-MOF nanosheets as the supporting material displayed better electrocatalytic properties than the 3D Co-MOF crystals for reduction of HO. The fabricated AuPt/2D Co-MOF exhibited high electrocatalytic activity, and the catalytic current was linear with HO concentration from 0.1 μM to 5 mM, and 5-60 mM with a low detection limit of 0.02 μM (S/N = 3). The remarkable electroanalytical performance of AuPt/2D Co-MOF can be attributed to the synergistic effect of the high dispersion of the AuPt NPs with the marvelous electrochemical properties and the 2D Co-MOF with high-specific surface areas. Furthermore, this sensor has been utilized to detect HO concentrations released from the human Hela cells. This work provides a new method for improving the performance of electrochemical sensors by choosing the proper support materials from diverse crystal morphology materials.