Boosting Hydrogen Production with Surface‑Amine‑Coated High‑Entropy Sulfides

A new study shows that adding amine groups to the surface of a mixed‑metal sulfide can make it much better at producing hydrogen from water. The material contains zinc, cadmium, cobalt, copper and manganese in a single crystal. By attaching ‑NH₂ ligands to the surface, scientists selectively activate cadmium atoms. The amine groups change how the material looks and behaves. They make thin, two‑dimensional sheets that expose more surface area. They also alter the electronic environment around cadmium atoms, making it easier for electrons to reach them. Because of these changes, the modified sulfide delivers a photocurrent three times higher than the unmodified version. The rate of hydrogen production jumps more than sixteen times. This means the material can generate hydrogen without needing extra catalytic particles.Spectroscopy and computer simulations explain why. The ‑NH₂ groups help cadmium’s 4d orbitals become more accessible to incoming electrons. They strengthen the bond between water molecules and the surface, lowering the energy needed for water to split and hydrogen to form. The overall effect is a much smoother, faster reaction. This work suggests that surface coordination—attaching specific molecules to the outer layer of a catalyst—is a powerful way to unlock the full potential of complex, high‑entropy materials. It opens a path toward efficient, catalyst‑free devices for clean energy.