Black Phosphorus-Based Semiconductor Heterojunctions for Photocatalytic Water Splitting

Solar-to-hydrogen (H₂ ) conversion has been regarded as a sustainable and renewable technique to address aggravated environmental pollution and global energy crisis. The most critical aspect in this technology is to develop highly efficient and stable photocatalysts, especially metal-free photocatalysts. Recently, black phosphorus (BP), as a rising star 2D nanomaterial, has captured enormous attention in photocatalytic water splitting owing to its widespread optical absorption, adjustable direct band gap, and superior carrier migration characteristics. However, the rapid charge recombination of pristine BP has seriously limited its practical application as photocatalyst. The construction of BP-based semiconductor heterojunctions has been proven to be an effective strategy for enhancing the separation of photogenerated carriers. This Minireview attempts to summarize the recent progress in BP-based semiconductor heterojunctions for photocatalytic water splitting, including type-I and type-II heterojunctions, Z-Scheme systems, and multicomponent heterojunctions. Finally, a brief summary and perspective on the challenges and future directions in this field are also provided.