Noble-metal-free Te-doping mediated band structure regulation of ZnIn2S4 for highly efficient NIR-driven H2 production

Despite extensive efforts over four decades, the development of efficient NIR-driven photocatalysts for solar H 2 production remains elusive. Current NIR-activated systems are limited by inferior performance, significant photocorrosion, and reliance on scarce noble metals or toxic dyes. Notably, NIR-activated systems based on non-noble metals that simultaneously exhibit high activity and long-term stability represent a critical gap. In this work, we present a Te-doping-induced band-structure optimization strategy, whereby Te-doped ZnIn 2 S 4 nanoflowers are synthesized via a one-step hydrothermal method, enabling a narrow-bandgap semiconductor to achieve efficient NIR-driven (λ > 800 nm) H 2 production without noble-metal co-catalysts through Urbach‑tail absorption. Te atom incorporation not only broadens light absorption and effectively narrows the bandgap through the formation of intermediate gap states, but also induces a redistribution of local charges, which facilitates the separation and transport of charge carriers. As expected, the optimized Te–ZnIn 2 S 4 catalyst delivers a remarkable hydrogen evolution rate of 128 μmol·g ‒1 ·h ‒1 under NIR irradiation (λ > 800 nm), which is 10 times higher than that of its pristine counterpart and outperforms all previously reported non‑noble‑metal NIR‑responsive photocatalysts under the same conditions. Impressively, the optimally Te-doped ZnIn 2 S 4 retains a considerable H 2 evolution rate of 8.57 μmol·g ‒1 ·h ‒1 under extended-wavelength NIR light (λ = 940 nm), demonstrating its exceptional capability to harvest low-energy photons for water splitting. This work highlights that rational band‑structure engineering through element doping can effectively extend the photoresponse of ZnIn 2 S 4 into the deep NIR region via Urbach‑tail absorption, thereby enabling efficient H 2 evolution without the need for noble‑metal co‑catalysts.