Co₃O₄ is an ideal p-type material for photoelectrochemical (PEC) hydrogen evolution, while serious electron-hole recombination restrict its further improvement of the PEC activity. The construction of traditional heterojunction can effectively solve this problem. However, the PEC water splitting efficiency is still tough to be satisfactory due to the inevitable generation of heterojunction interface defects. Herein, we fabricate the epitaxial growth of FeS nanowires at an angle of 60° on the Co₃O₄ nanosheets via electrostatic adsorption and form SO bonds at the interface. The cactus-like heterojunction overcomes the problem of the large interfacial defects of heterojunction and improves the separation efficiency of photogenerated carriers. As a result, a photocurrent density of Co₃O₄/FeS is 9.953 mA cm⁻² at 0 V_RHE for 22 h without any obvious decay, which is approximately 10 times higher than that for pristine Co₃O₄ (0.966 mA cm⁻² at 0 V_RHE), greatly improving the efficiency of PEC water splitting and stability. It is better than most Co₃O₄-based photocathodes without cocatalyst and even comparable with the advanced Co₃O₄-based photocathodes. This work significantly addresses the issue of interfacial defects in heterojunction and provides constructive guidance for the construction of perfect interfacial heterojunction in the future.

Co ₃ O ₄是一种理想的光电化学(PEC)析氢p型材料，但严重的电子-空穴复合限制了其进一步提高PEC活性。传统异质结的构建可以有效解决这个问题。然而，由于不可避免地产生异质结界面缺陷，PEC水分解效率仍然难以令人满意。在此，我们通过静电吸附在Co ₃ O ₄纳米片上以60°角外延生长FeS纳米线并形成S界面处的 O 键。仙人掌状异质结克服了异质结界面缺陷大的问题，提高了光生载流子的分离效率。结果，Co ₃ O ₄ /FeS 的光电流密度为 9.953 mA cm ^-2在 0 V _{RHE下 22 h 没有任何明显衰减，这大约是原始 Co 3} O ₄ (0.966 mA cm ) 的 10 倍^-2 at 0 V _RHE )，大大提高了 PEC 水分解的效率和稳定性。它优于大多数不含助催化剂的 Co ₃ O ₄基光电阴极，甚至可与先进的 Co₃ O ₄基光电阴极。该工作显着解决了异质结的界面缺陷问题，为未来构建完美的界面异质结提供了建设性的指导。