Ag/AgVO ₃ /g-C ₃ N ₄ Ternary Nanocomposites for Enhanced Photo- and Electrocatalytic Hydrogen Evolution: Synergistic Charge Separation and Interfacial Engineering

Nanocomposite catalysts are advantageous for photo/electrocatalysis due to their exceptional stability, charge transfer efficiency, and interfacial interactions. Conventional semiconductor photocatalysts, such as g-C3N4, face challenges like high charge recombination rates and insufficient catalytic sites. To address these issues, silver (Ag) nanoparticles and AgVO3 nanowires were integrated onto the g-C3N4 surface to synthesize Ag/AgVO3/g-C3N4 nanocomposites for water splitting. XRD and XPS analyses confirm the successful integration of silver vanadate onto the g-C3N4 matrix, revealing the presence of Ag/AgVO3 and g-C3N4. The morphology demonstrates the crystalline nature and strong interfacial connections between g-C3N4 and Ag/AgVO3, suggesting enhanced photocatalytic performance. Compared to individual Ag/AgVO3 and g-C3N4 components, the Ag/AgVO3/g-C3N4 catalyst exhibits significantly higher photo/electrocatalytic H2 production rates. The highest photocatalytic H2 yield of 3602 μmol·g–1 was produced with the 15% Ag/AgVO3/g-C3N4 heterostructure, surpassing the yields of Ag/AgVO3 and g-C3N4 by 8.7 and 22.3 times, respectively. Additionally, the 15% Ag/AgVO3/g-C3N4 catalyst demonstrates improved reaction kinetics in the hydrogen evolution reaction with a lower overpotential of 112 mV and a Tafel slope of 63 mV/dec in 1 M KOH. The exceptional photo/electrocatalytic performance of the 15% Ag/AgVO3/g-C3N4 nanocomposite is attributed to efficient charge separation and optimal interfacial interactions among Ag, AgVO3, and g-C3N4, facilitating electron transport and reducing charge recombination. This study proposes a highly efficient g-C3N4-based catalyst design with significant potential for energy conversion applications in photo- and electrocatalysis.