Experimental dataset of nanoporous GaN photoelectrode supported on patterned sapphire substrates for photoelectrochemical water splitting.

GaN is one of the most promising materials for high PEC efficiency to produce clean, renewable hydrogen in an ecofriendly manner (Ebaid et al., 2015; Kamimura et al., 2017; Yang et al., 2018; Ohkawa et al., 2013). Trough assays of nanoporous gallium nitride (GaN) photoelectrode, we recently demonstrated an improved PEC efficiency and photocurrent density of nanoporous GaN photoelectrode by 470% times with respect to planar counterpart (Li et al., 2019). Here, we report original data acquired under UV-visible spectrometer, X-ray diffraction (XRD), room temperature PL measurements and PEC measurements, based on the characterization of different sapphire substrate, different GaN samples and different GaN photoelectrodes. The optical properties and photoelectrochemical properties of the corresponding samples and possible mechanisms are presented, which is freely available (Li et al., 2019). The data can be valuable for researchers interested in photoelectrochemical water splitting, as well as to researchers developing fabrication of nanoporous photoelectrode. For more insight please see the research article "A nanoporous GaN photoelectrode on patterned sapphire substrates for high-efficiency photoelectrochemical water splitting", https://doi.org/10.1016/j.jallcom.2019.06.234.

Fabrication of GaN truncated nanocone array using a pre-deposited metallic nano-hemispheres template for efficient solar water splitting.

The GaN truncated nanocone is an excellent candidate for better photoelectrochemical efficiency than other GaN nanostructures. Here the highly ordered GaN truncated nanocone array was fabricated using a pre-deposited metallic nano-hemispheres template on a wafer scale. The highly ordered profiles of pre-deposited metallic nano-hemispheres template were defined by anodic aluminum oxide (AAO) masks through electron beam evaporation. The formation mechanism for the profiles of nano-hemispheres and GaN truncated nanocones were investigated. The results elucidate that proper selection of AAO parameters enables controllability of desired profiles and depth of Cr nano-hemispheres template, further controllability of desired profiles and depth of the GaN truncated nanocones. The optical and photoelectrochemical characterizations show the substantial improvements in ultraviolet light absorption and photoelectrochemical efficiency with photocurrent density by 300% times with respect to planar counterpart. The presented synthetic strategy will pave the way towards low-cost and mass production of GaN truncated nanocone photoelectrode for efficient photocatalysis.