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 junction 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 junction 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 junction-induced interfacial orbital hybridization for precise d-band center regulation.