The development and utilization of photocatalysts to realize water-splitting without any external bias or sacrificial agents has received the limelight. As a novel two-dimensional layered material, metal phosphorus trichalcogenides (MPTs) cause wide research interest, presently. However, the growth of ultrathin two-dimensional MPT crystals is a great challenge to hinder their application. Here, we initially grow few-atomic layered nickel phosphorus trisulfide (NiPS₃) as promising photocatalyst for hydrogen evolution. The as-prepared NiPS₃ hexagonal nanosheet, as thin as few atomic layers (≤ 3.5 nm), has lateral size of larger than 15 µm. These ultrathin NiPS₃ crystals can directly generate hydrogen gas from pure water without any sacrificial agents under sunlight. With ultraviolet photoelectron spectrometer and electrochemical impedance spectroscopy, we show that the attractive photocatalytic activity of the ultrathin NiPS₃ crystals arise from their appropriate positions of the band edges. This discovery is expected to make a contribution to develop next generation solar-fuel conversion catalysts for H₂ production.

在没有任何外部偏压或牺牲剂的情况下，光催化剂的开发和利用以实现水分解已成为人们关注的焦点。作为一种新型的二维层状材料，金属三卤化磷（MPT）引起了广泛的研究兴趣。然而，超薄二维MPT晶体的生长是阻碍其应用的巨大挑战。在这里，我们最初生长很少原子的层状三硫化镍磷（NiPS ₃）作为有希望的光催化氢析出催化剂。制备的NiPS ₃六角形纳米片薄至只有几个原子层（≤3.5 nm），其横向尺寸大于15 µm。这些超薄NiPS ₃在阳光下，晶体可以直接从纯净水中产生氢气，而无需使用任何牺牲剂。借助紫外光电子能谱仪和电化学阻抗谱，我们表明，超薄NiPS ₃晶体的诱人光催化活性来自其能带边缘的适当位置。该发现有望为开发用于H ₂生产的下一代太阳能转换催化剂做出贡献。