Infrared (IR) light, which occupies almost half of all solar energy has been an untapped energy source up to date. The solar fuel production using the IR region of light hold the key to full utilization of solar energy. The localized surface plasmon resonance (LSPR), which is tunable by the size, composition, doping ratios, is a promising phenomenon realizing the light-harvesting ability in the IR region. Here, we report the IR-responsive photocatalyst composed of CdS and plasmonic Cu₉S₅, which break the record of IR-light induced photocatalytic hydrogen evolution reaction (apparent quantum yield = 4.4% at 1100 nm). Based on the simulation of the energy band at the p − n junction between plasmonic Cu₉S₅ and CdS, the careful tuning of the CdS domain size archived the record-breaking photocatalytic activity. The optimization of the “plasmonic” p–n junction is a key for a highly efficient IR-responsive photocatalyst.

迄今为止，几乎占所有太阳能一半的红外 (IR) 光一直是一种尚未开发的能源。利用红外光区生产太阳能燃料是充分利用太阳能的关键。局部表面等离子共振（LSPR）可通过尺寸、成分、掺杂比进行调节，是实现红外区域光捕获能力的有希望的现象。在这里，我们报告了由 CdS 和等离子体 Cu ₉ S ₅组成的红外响应光催化剂，它打破了红外光诱导的光催化析氢反应的记录（表观量子产率 = 4.4%，在 1100 nm）。基于对等离激元 Cu ₉ S _{5之间 p - n 结处能带的模拟}和 CdS，CdS 域大小的仔细调整归档了破纪录的光催化活性。“等离子体”p-n结的优化是高效IR响应光催化剂的关键。