C@SiNW/TiO(2) Core-Shell Nanoarrays with Sandwiched Carbon Passivation Layer as High Efficiency Photoelectrode for Water Splitting

One-dimensional heterostructure nanoarrays are efficiently promising as high performance electrodes for photo electrochemical (PEC) water splitting applications, wherein it is highly desirable for the electrode to have a broad light absorption, efficient charge separation and redox properties as well as defect free surface with high area suitable for fast interfacial charge transfer. We present highly active and unique photoelectrode for solar H(2) production, consisting of silicon nanowires (SiNWs)/TiO(2) core-shell structures. SiNWs are passivated to reduce defect sites and protected against oxidation in air or water by forming very thin carbon layer sandwiched between SiNW and TiO(2) surfaces. This carbon layer decreases recombination rates and also enhances the interfacial charge transfer between the silicon and TiO(2). A systematic investigation of the role of SiNW length and TiO(2) thickness on photocurrent reveals enhanced photocurrent density up to 5.97 mA/cm(2) at 1.0 V vs.NHE by using C@SiNW/TiO(2) nanoarrays with photo electrochemical efficiency of 1.17%.