Well Controlled 3D Iridium Oxide/Platinum Nanocomposites with Greatly Enhanced Electrochemical Performances

It is crucial to improve charge storage capacity (CSC) and charge transport efficiency with low impedance for electrochemical capacitors. Here, a well-controlled three-dimensional (3D) nanocrystal platinum (Pt) is electrodeposited as the intermediate layer on microelectrode (200 mu m in diameter) to provide extensive large surface area, followed by introducing iridium oxide (IrOx) nanoparticles with excellent adhesion on the rough layer to fabricate high-performance IrOx/Pt composite coatings. The uniform flower-shaped coating presents a significantly low impedance approximate to 2.01 k omega at 1 kHz (reduction of 94.52%). It has a cathodic CSC (CSCc) up to approximate to 200.64 mC cm(-2), about 2, 17.51, and 56.18 times higher than that of nanocrystal Pt, IrOx, and flat Pt respectively. Robust chronic stability is observed with CSCc at approximate to 171.97 mC cm(-2) after electrical stimulation for 12 d (>1 x 10(8) cycles). It also demonstrates record-high charge injection capacity approximate to 6.37 mC cm(-2) with excellent biocompatibility. Such coating is widely applicable for batch production on multichannel microelectrode arrays or substrates with different sizes. Moreover, it promotes excellent sensitivity to glucose detection up to approximate to 130 mu A cm(-2) mm(-1), with a linear range of 1-30 x 10(-3) m and a detection limit of 1.08 x 10(-6) m. The promising coating will pave a new way for various electrochemical applications.