Synergetic NIR responsive plasmonic CuxS Nanodisks on CuO photocathodes for photo-electrochemical water splitting
Mohit Kumar, Anshid Kuttasseri, Bhagatram Meena, Arup Mahata, Subrahmanyam Challapalli
Abstract
Solar energy is a promising source for producing renewable hydrogen and harvesting the near infrared(NIR∼52 %) radiation. Herein, we synthesized Cu x S nanodisks(NDs) with characteristic LSPR absorption in NIR, coupled with CuO NPs(E g 1.6 eV) fabricating CuO/Cu x S NDs photocathode for PEC water splitting . CuO/Cu x S NDs delivered higher J, ABPE in alkaline (−10.3 mA cm −2 , 3 % at 0.34 V RHE ) and neutral (−9.5 mA cm −2 , 1.15 % at 0.2 V RHE ) conditions, surpassing CuO photocathodes by more than 3 and 3.3−times, respectively. Electrochemical studies suggested increased charge−carrier concentration, efficient charge−transfer, elongated lifetime of photogenerated electron owing to intimate contact between layers leading to internal electric field enhancement, charge separation. H 2 production over CuO/Cu x S photocathode was 80 µmol.cm −2 .h −1 , η F =86 %. DFT calculation underscores engineered CuO/Cu x S substantially improves catalytic HER efficiency by tuning charge transfer, optimal ΔG H* at heterointerface. The study conveys principles applicable to various domains, facilitating the creation of vacancies in superior semiconducting materials for photo-electrocatalysts.