Facile synthesis of BaCeO₃@g-C₃N₄ n-type semiconductor heterojunctions for green hydrogen production via multimodal photo and electro-catalytic pathways

Development of an efficient and stable catalytic system for the production of sustainable hydrogen has remained a pivotal challenge in photocatalysis and electrocatalysis. In this work, we have reported a facile calcination strategy for synthesizing n-type BaCeO₃@g-C₃N₄ heterojunctions that synergistically integrate the strong visible-light response of g-C₃N₄ with the high ionic conductivity and redox versatility of BaCeO₃ perovskite. The BaCeO₃@g-C₃N₄ heterojunction formation was confirmed through XRD, SEM, HR-TEM, and XPS techniques. The BaCeO₃ nanoparticles were found to be evenly anchored on g-C₃N₄ nanosheets post-calcination as compared to non-calcined BaCeO₃@g-C₃N₄. The as-prepared heterostructures exhibited remarkable activity under different water-splitting conditions. The optimized 20% BaCeO₃@g-C₃N₄ demonstrated enhanced photochemical (PC) H₂ production performance (15.21 mmol g_cat⁻¹ h⁻¹) compared to pristine g-C₃N₄ and BaCeO₃. Electrochemical (EC) and photoelectrochemical (PEC) investigations also corroborated its advanced HER activity at low overpotentials. The superior H₂ evolution activity is attributed to the optimized band alignment and the interfacial charge transfer between g-C₃N₄ and BaCeO₃. This work presents a multimodal H₂ production activity of BaCeO₃@g-C₃N₄ heterojunctions via photochemical and photo-/electrochemical methods.