Mesoporous hollow W₁₈O₄₉ spheres were fabricated by a facile solvent-induced assembly method using anhydrous WCl₆ as a precursor and CH₃COOH as a solvent. This unique structure exhibited remarkably enhanced photocatalytic and photoelectrocatalytic performance than other morphologies like urchin and nanowire due to the simultaneous enhancement in light harvesting, surface area and adsorption capability.