In situ growth of g-C3N4 on clay minerals of kaolinite, sepiolite, and talc for enhanced solar photocatalytic energy conversion

The clay mineral/g-C 3 N 4 composites were prepared through a simple one-pot synthesis with acid-treated clay minerals and melamine as precursors. Three typical clay minerals, e.g., kaolinite , sepiolite , and talc, were adopted as photocatalyst carriers. Notably, the acid-treated clay minerals coupled with g-C 3 N 4 in three different ways. The kaolinite/g-C 3 N 4 composite, in particular, proceeded with an intercalation reaction due to the in situ growth of g-C 3 N 4 within the layers of acid-treated kaolinite, leading to the expansion of kaolinite layers and a prominently large specific surface area of 61.9 m 2  g −1 . The resultant composites were used in photocatalytic H 2 generation by water splitting and CO 2 reduction, exhibiting superior photocatalytic performance to the g-C 3 N 4 . Among the obtained composites, the optimized kaolinite/g-C 3 N 4 showed the best photocatalytic activities , e.g. 3.03 μmol g −1  h −1 of CO evolution and 385 μmol g −1  h −1 of H 2 evolution, compared with merely 0.91 μmol g −1  h −1 of CO evolution and 96.4 μmol g −1  h −1 of H 2 evolution for bare g-C 3 N 4 . The superior performance of kaolinite/g-C 3 N 4 can be ascribed to the large specific surface area and better distribution of g-C 3 N 4 , which can enhance the light absorption , increase the number of active sites and favor the charge separation.