Controllable growth of BiOCl film with high percentage of exposed {0 0 1} facets

Bismuth oxychloride (BiOCl) granular and flake-like films with specific {0 0 1} crystal facets are synthesized by a facile hydrolysis route. The percentage of reactive {0 0 1} facets is up to 97.36% in granular film and 91.69% in flake-like film, respectively. It is found that the synthesized granular film is composed by the nano grains with average size around 5-10 nm, but the flake-like film contains the flakes originated from the large nano crystals. The percentage of the {0 0 1} reactive facets and morphology of the BiOCl film can be tuned by adjusting the concentration or the pH value of the solution during the synthesis process, companied with the appearance of the (1 0 1), (1 0 2), and (1 1 0) facets. The formation mechanism of {0 0 1}-preferential orientation has been rationally explained in terms of crystal growth habit and dynamics. Photocatalytic degradation of RhB dye has been observed under UV light, representing that the flake-like film with {0 0 1} facets preferred orientation exhibits excellent photoactivity.