Synergistic g-C3N4/CoAl-LDH heterojunctions for superior visible-light-driven hydrogen evolution and wastewater treatment

The pursuit of cost-effective, durable, and high-performance photocatalysts remains a key challenge for achieving sustainable hydrogen generation. In this work, we designed and synthesized a novel series of g-C₃N₄/CoAl-LDH hybrid nanostructures through a simple hydrothermal process. Their crystallographic framework, surface morphology, elemental distribution, and porosity were systematically examined using XRD, SEM, XPS, and N₂ adsorption–desorption techniques. The cooperative effect between Co²⁺ redox-active centers and the hydroxyl-enriched layered double hydroxide surface significantly accelerates hydrogen evolution kinetics, while the tailored band alignment broadens absorption in the visible-light region. Owing to these advantages, the optimized g-C₃N₄/CoAl-LDH catalyst delivered an outstanding hydrogen production rate of approximately 3033 μmol g⁻¹ h⁻¹ under visible-light irradiation, which is more than 7 times higher than that of bare CoAl-LDH (~ 430 μmol g⁻¹ h⁻¹). Transient photocurrent measurements further confirmed rapid and stable photo-induced charge transport, highlighting efficient carrier separation under illumination. Moreover, the composite exhibited excellent long-term durability and recyclability, underscoring its strong potential for future applications in photocatalytic hydrogen evolution and wastewater remediation.