“…[8][9][10][11][12][13][14][15] Hence, nano-energy materials, particularly nano-metal oxides, manifest unique properties, e.g., light-to-plasmon resonance, which can be further applied to improve the performance of solar cells, optical sensors, and gas sensors. [16][17][18][19][20] Among these nanometal oxides, ZnO, a typical material for photocatalysts and sensors, displays promising application potential due to its high photosensitivity, low cost, and stability. 6,7,9,10,21 Furthermore, vertically aligned ZnO nanorods (ZnONRs), thanks to the high length/diameter ratio, high surface area, and short electron-hole pair separation distance, are the optimum morphology to improve the light absorption ability, leading to enhanced efficiency of light-driven photoelectrochemical (PEC) water splitting.…”