Intense interaction between biochar/g-C3N4 promotes the photocatalytic performance of heterojunction catalysts

Abstract

In recent decades, environmental protection and energy issues have gained significant attention, and the development of efficient, environmentally friendly catalysts has become especially crucial for the advancement of photocatalytic technology. This study employs the sintering method to produce biochar. A hybrid photocatalyst for the degradation of RHB under visible light was prepared by loading varying proportions of biochar onto g-C₃N₄ using ultrasonic technology. Among them, 2% CGCD (2% biochar/g-C₃N₄) achieved a degradation rate of 91.3% for RHB after 30 minutes of visible light exposure, which was more than 25% higher than GCD (g-C₃N₄), and exhibited a higher photocurrent intensity and lower impedance value. The enhancement in photocatalytic activity is primarily attributed to the increased utilization efficiency of visible light and the electron transfer channel effect from a minor amount of biochar, effectively reducing the recombination of photo-generated charge carriers on the g-C₃N₄ surface, thereby significantly improving photocatalytic activity. The degradation of RHB is synergistically mediated by O₂⁻, h⁺ (photo-generated holes), and ˙OH. The free radical capture experiment indicates that O₂⁻ and ˙OH are the primary active components, followed by h⁺.