Boosting photocatalytic H2O2 production by coupling of sulfuric acid and 5-sulfosalicylic acid incorporated polyaniline with g-C3N4

Abstract

In this study, graphitic carbon nitride (g-C₃N₄, CN) was decorated with polyaniline (PANI), which was incorporated with inorganic (H₂SO₄) and organic (5-sulfosalicylic acid, SSA) acids for photocatalytic H₂O₂ production under simulated solar irradiation. The PANI/CN sample exhibited H₂O₂ production of approximately 1.5 mM within 3 h, which is much higher than that of either CN or PANI alone in the presence of AgNO₃ solution. The increased photocatalytic activity for H₂O₂ production could be ascribed to the extended visible-light absorption, large specific surface area, and reduced electrical resistance as well as the appropriate redox potential. It should be noted that doping of H₂SO₄ on PANI could lead to a high oxidation level, which can increase the electrical conductivity of PANI/CN, while the doping of SSA on PANI may induce delocalization and, hence, the enlargement of the specific surface area of PANI. Additionally, CN could afford electron transit through π–π* between the conjugate units of PANI and its tri-s-triazine units, facilitating effective separation for photoexcited electron–hole pairs. This study demonstrated that the doping of PANI with H₂SO₄ and SSA and coupling with g-C₃N₄ is a promising technique for photocatalytic H₂O₂ production utilizing solar energy.