Schottky-like contact-induced d-band center shift in Cu(H2PO3)2/boron for efficient photocatalytic hydrogen evolution

Abstract

To overcome the inherent limitations of conventional photocatalysts, this work presents the rational design of a boron-regulated copper hydrogen phosphite (Cu(H₂PO₃)₂) composite integrated with a Schottky-like contact via an in situ hydrothermal approach, employing elemental boron as an efficient non-noble metal cocatalyst. The composite features a three-dimensional interpenetrating architecture, wherein coherent interfacial growth between boron and Cu(H₂PO₃)₂ induces lattice strain that enhances electronic coupling, while the hierarchical mesoporous structure promotes proton transport and increases the accessibility of active sites. The optimized Cu(H₂PO₃)₂/boron composite demonstrates a notable visible-light-driven hydrogen evolution rate of 1711 µmol h⁻¹ g⁻¹, which is 25 times higher than that of the individual constituents. Mechanistic studies indicate that the incorporation of boron introduces intermediate energy states to broaden the optical absorption range and modulates the d-band center position of Cu(H₂PO₃)₂. Concurrently, the interfacial Schottky-like contact facilitates directional electron transfer from Cu(H₂PO₃)₂ to boron via a built-in electric field, which significantly lowers charge transfer resistance and suppresses electron–hole recombination. Moreover, the composite exhibits outstanding photocatalytic stability over repeated 20-hour cycling tests. This study establishes a novel paradigm for developing high-performance, noble-metal-free photocatalysts by leveraging Schottky-like contact-induced interfacial orbital hybridization for precise d-band center regulation.