A low-cost and high-yield approach for preparing g-C3N4 with a large specific surface area and enhanced photocatalytic activity by using formaldehyde-treated melamine

Abstract

Graphitic carbon nitride (g-C3N4) is a promising material for photocatalytic environmental purification. However, the application of g-C3N4 has been limited by its synthetic processes, where a low-cost and high-activity synthetic method could promote its application. Here, by utilizing formaldehyde and changing the thermal condensation processes, g-C3N4 with a large specific surface area was obtained, and its photocatalytic activity was 12.3 and 6.5 times that of pristine g-C3N4 for photocatalytic organic pollutant degradation and photocatalytic water splitting, respectively. The enhanced photocatalytic performance can be attributed to the large specific surface area, which reached 137.3 m2/g, as well as the improved efficiency of the separation and transfer of charge carriers. Moreover, the additional trace amounts of formaldehyde can increase the yield of g-C3N4, and the yield reached 21%, which is 7 times that obtained with traditional thermal condensation processes.