Scalable Core–Shell MoS2/Sb2Se3 Nanorod Array Photocathodes for Enhanced Photoelectrochemical Water Splitting

Abstract

Photoelectrochemical (PEC) hydrogen generation is a promising solar energy harvesting technique to address the concerns about the ongoing energy crisis. Antimony selenide (Sb2Se3) with van der Waals‐bonded quasi‐1D (Q1D) nanoribbons, for instance, (Sb4Se6)n, has attracted considerable interest as a light absorber with Earth‐abundant elements, suitable bandgap, and a desired sunlight absorption coefficient. By tuning its anisotropic growth behavior, it is possible to achieve Sb2Se3 films with nanostructured morphologies that can improve the light absorption and photogenerated charge carrier separation, eventually boosting the PEC water‐splitting performance. Herein, high‐quality Sb2Se3 films with nanorod (NR) array surface morphologies are synthesized by a low‐cost, high‐yield, and scalable close‐spaced sublimation technique. By sputtering a nonprecious and scalable crystalline molybdenum sulfide (MoS2) film as a cocatalyst and a protective layer on Sb2Se3 NR arrays, the fabricated core–shell structured MoS2/Sb2Se3 NR PEC devices can achieve a photocurrent density as high as −10 mA cm−2 at 0 VRHE in a buffered near‐neutral solution (pH 6.5) under a standard simulated air mass 1.5 solar illumination. The scalable manufacturing of nanostructured MoS2/Sb2Se3 NR array thin‐film photocathode electrodes for efficient PEC water splitting to generate solar fuel is demonstrated.