Improved photoelectrochemical water oxidation under visible light with mesoporous CoWO4

• Synthesis of mesoporous CoWO4 nanoparticles.
• Amphiphilic organosilane surfactant was utilized to generate mesoporosity.
• Significantly improved visible-light-driven photoelectrochemical water oxidation with mesoporous CoWO4.

Herein, a hydrothermal synthesis of nanocrystalline cobalt tungstate (m-CoWO4) with mesoporous texture in the presence of amphiphilic organosilane surfactant is described. As-prepared nanocrystals are spherical in shape with size between 8 and 10 nm consisting of monoclinic (wolframite structure) phase. In addition, these nanocrystals are endowed with high surface area (50 m2 g−1), textured mesoporous surface and absorption threshold into visible region. Furthermore, these textured and fine nanocrystals exhibit improved photoelectrochemical activity (PEC), as compared to non-mesoporous CoWO4, under visible light (λ>420 nm) for water oxidation in a photoelectrochemical cell.