Development of a Chemical Solution Method to Improve the Photoelectrochemical Hydrogen Production Performance of Antimony Sulfide (Sb₂S₃) Photoelectrode

Abstract

Global energy consumption is increasing as the world's population and industries expand. Photoelectrochemical hydrogen production holds great potential to solve the energy crisis and achieve the goal of carbon neutrality. Fabrication of highly efficient photoanode via cost effective method remains key challenges. Herein, we utilized a chemical solution method and rapid thermal annealing (RTA) process fabricated an efficient antimony sulfide (Sb₂S₃) photoanode. We showed that the TiO₂ bottom layer holds the key role in the Sb₂S₃ film formation and properties. By adjusting the TiO₂ bottom layer, we are able to synthesize a high uniformity and coverage Sb₂S₃ film with excellent light absorption ability. Besides, the RTA process can facilitate the Sb₂S₃ phase growth and formation, generating a high quality Sb₂S₃ film with large grain and crystallite size. The RTA annealed sample exhibits highest photocurrent density compared to other annealing method, which shows the high effectiveness of RTA methods. As a result, fabricated Sb₂S₃ photoanode showing a high photocurrent density of 3.2 mA/cm² at 1.23 V vs. RHE, which is one of the highest values among all reported Sb₂S₃ photoanode (without OEC and protection layer). Furthermore, we demonstrated an iodide oxidation reaction (IOR) to replace the sluggish OER to show the effectiveness of our Sb₂S₃ photoanode. Interestingly, we achieved a highest photocurrent density value of 7.7 mA/cm² at 0.6 V vs. RHE. Our work provides a cost-effective method for fabricating high efficiency Sb₂S₃ photoanode, paving the way for developing highly active sulfide based photoanode in the future.