Engineering a light-active CoO/D-CN catalyst for dual-functional enhanced BPA degradation and hydrogen evolution.

Owing to the current energy and environmental crisis, the design of efficient catalysts is a critical necessity. A visible-light-responsive cobalt monoxide-based heterojunction was engineered to achieve efficient bisphenol A (BPA) degradation and hydrogen (H2) evolution. For the formation of the heterojunction, structurally defective graphitic carbon nitride (g-C3N4) (abbreviated as D-CN) was designed by adding ascorbic acid during the synthesis of the g-C3N4. The close interface between the CoO and D-CN prevents fast charge recombination, as confirmed by the enhanced photocatalytic response and reduced photoluminescence intensity. XRD, XPS, BET surface area, TEM/SEM and EDX analyses reveal a uniform CoO composition on the D-CN matrix. In comparison to the individual components, the optimized composite shows an approximately three-fold increase in H2 generation under visible-light illumination and a significantly better photocatalytic BPA degradation rate. This work demonstrates a synergistic approach that uses a straightforward, non-hazardous photocatalyst design to combine environmental restoration with solar fuel generation.