Commercial-scale reproducible GaN nanowires with 6.4% solar to hydrogen conversion efficiency in photoelectrochemical water splitting

In this article, we demonstrate how commercial-scale reproducible GaN nanowires (GNWs) passivated with metal oxide overlayers and assisted by an efficient co-catalyst with a visible absorption wavelength can be used as a high-performance photoanode for photoelectrochemical (PEC) water splitting to produce solar-driven hydrogen. The facile growth of GNWs using a vapor-liquid-solid method by metal-organic chemical vapor deposition (MOCVD) raises the density of the NWs, increasing the active area for the water splitting reaction and facilitating charge transport. The passivation of surface defects through overlayers and being aided by a co-catalyst with a photo absorption range in the visible region greatly increases the photocurrent density up to 4.6 mA/cm2 under 1 sun illumination at zero applied biasing versus the reference electrode. The measured solar to hydrogen conversion efficiency of 6.4% is among the highest documented values for GNWs-based photoanodes grown using MOCVD.