A facile and cost-efficient method to fabricate a mesoporous structured WO 3 photoanode was implemented for use in a tandem dual water splitting photoelectrochemical cell. Semi-transparent thin films of tungsten trioxide were fabricated by sol-gel process, incorporating a block co-polymer to induce a template-directed mesoporous structure. These thin films are deposited by dip coating onto transparent conducting oxide substrates and crystallized at a low temperature of 400°C in air. These thin film photoanodes exhibit a photocurrent of up to 0.6 mA/cm² in potassium phosphate buffers of pH 2, 4, and 6 at 1.23 V vs. RHE under 300 mW/cm² visible (400 – 900 nm) light irradiation with a faradic efficiency of up to 75%. Furthermore, we have demonstrated that corrosion occurs in electrolytes of pH > 4. The faradic efficiencies in varying pH solutions however suggest that parasitic redox reactions occurs in acidic conditions, limiting the O 2 production and demonstrating the need for stable surface co-catalysts to increase faradic efficiencies. In neutral conditions, protective layers and/or co-catalysts are needed for increasing WO 3 photoanode stability.