2D/2D MOF/MXene Schottky Junction: Prolonged Carrier Lifetime and Enhanced Hydrogen Evolution Efficiency

Abstract

Harnessing sunlight for photocatalytic overall water splitting offers a sustainable approach to renewable hydrogen (H₂) production, addressing global energy and environmental challenges. However, the development of efficient and durable photocatalysts remains a significant obstacle. This study introduces the design and performance of a 2D/2D Schottky heterojunction composed of Cu₂[CuTCPP] MOF of nanometric size and exfoliated Ti₃C₂ MXene for visible-light-driven overall water splitting. By leveraging the extensive interfacial contact between the two components, an interfacial electric field is generated, promoting efficient charge migration and prolonging carrier lifetimes, as confirmed through systematic density functional theory simulations, in situ irradiation X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy, and X-ray absorption spectroscopy. Ti₃C₂ MXene, acting as a cocatalyst for photohole transport and accumulation, reduces oxidative degradation and slows catalyst deactivation. The synergistically enhanced light absorption properties of the Cu₂[CuTCPP]/Ti₃C₂ heterojunction result in an impressive H₂ evolution rate exceeding 5000 µmol g_cat⁻¹, underscoring its potential for next-generation photocatalytic systems in renewable energy applications.