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In this work, sand/zinc oxide (ZnO)/titanium dioxide (TiO2)-based photocatalysts were hybridized with graphene oxide (GO) and GO_multi-walled carbon nanotubes (MWCNTs) hybrid solution. The novel hybrid was then used in photocatalysis to degrade dye contamination. The nanocomposite photocatalyst was initially fabricated by growing ZnO nanorods (NRs) via sol-gel immersion followed by synthesizing TiO2 NRs for different times (5 and 20 h) using a hydrothermal method on sand as a substrate. Prior to the hybridization, the initial GO was synthesized using electrochemical exfoliation and further mixed with 1 wt% MWCNTs to form GO_MWCNTs hybrid solution. The synthesized GO and GO_MWCNTs hybrid solution were then incorporated onto sand/ZnO/TiO2 nanocomposite-based photocatalysts through immersion. Various sand/ZnO/TiO2-based photocatalysts were then tested for methylene blue (MB) dye degradation within 3 days. On the basis of UV-Vis measurement, the highest MB degradation was achieved by using sand/ZnO NRs/TiO2 NRs (5 h)/GO_MWCNTs (92.60%). The high surface area and high electrical conductivity of GO_MWCNTs prolonged the lifetime of electron/hole separation and thus enhanced the photocatalytic performance.

In this work, a nanocomposite photocatalyst was fabricated by growing zinc oxide (ZnO) and titanium dioxide (TiO2) on the sand as a substrate. The initial sand/ZnO was fabricated via sol-gel immersion method for 4 h at 95℃. Furthermore, the sand/ZnO/TiO2 was fabricatedusing hydrothermal method for 5 h at 150℃. Based on field emission scanning electron microscopy (FESEM) analysis, the fabricated sand/ZnO/TiO2 consists of random formation of hexagonal ZnO nanorods and two pyramidal spindle ends of TiO2 nanorods. The addition of TiO2 on top of ZnO nanorods increased the number of active sites which enables more contaminants to be absorbed thus enhanced the photocatalysis process. Moreover, based on the micro-Raman spectra, the synthesized TiO2 was in rutile phase and the ZnO peak was unobservable due to the overlapping with TiO2 peak. Based on its morphological and structural properties, the fabricated sand/ZnO/TiO2 nanocomposite was potential to be applied as photocatalyst.