Activated-Carbon-Templated Crystalline Tantalates for Photocatalytic Water Splitting

Herein, we report a facile nanocasting route for the preparation of crystalline mesoporous Ta₂O₅ and NaTaO₃ with a high surface area using activated carbon as the structure-directing hard template. The crystalline particles of Ta₂O₅ and NaTaO₃ have mean sizes of 6 and 9 nm, constructing mesoporous networks with surface areas of 91 and 75 m² g⁻¹, respectively. The photocatalytic performances of the tantalum-based replicas were investigated for the water splitting reaction by using methanol as sacrificial agent and better photocatalytic performances were observed in comparison with bulk and amorphous counterparts. Loading the templated Ta₂O₅ and NaTaO₃ with 1 wt % NiO_x boosted their photocatalytic activity. The most-active sample, NaTaO₃/NiO_x, was also tested for overall water splitting and it produced hydrogen and oxygen in stoichiometric ratios at rates of 129 and 66 μmol h⁻¹, respectively