Fig. 1: HAAPP synthesis strategy.

a Operation diagram of the HAAPP strategy; b Digital photographs of the sample in each step; c Mechanism description about the growth processes of the HAAPP strategy; d LaMer model for description of the crystal growth processes; Digital photographs of the samples e once adding concentrated HCl and f after shaking for ~5 min; g Comparison of products with (left) and without (right) UV irradiation during synthesis; Digital photographs of the products obtained by mass preparation under h room light and i 365 nm UV light