Synthesis of a hydrophilic α-sulfur/PDA composite as a metal-free photocatalyst with enhanced photocatalytic performance under visible light

The polydopamine (PDA) coating alpha-S hydrophilic composites (S-D) were fabricated by a self-assembly process for enhanced alpha-S photocatalytic performance under visible light. The XRD patterns analysis indicated that we had successfully prepared the orthorhombic alpha-S. The SEM, FT-IR and TGA showed that PDA had been successfully coated on alpha-S. The photocatalytic ability was illustrated by the DRS and FL. Moreover, the measurement of the water contact angle of S-D and the corresponding original alpha-S (S-A) showed the hydrophilicity of alpha-S had been improved. The photocatalytic ability of S-D and S-A was evaluated by photocatalytic decomposition of Methylene blue (MB) solution. The MB elimination rate with S-D in the photocatalytic process was 2.46 times as great as that with S-A under visible light. The enhanced photocatalytic ability could be attributed to the improved hydrophilicty of alpha-S.