In2S3/AgIO3 photoanode coupled I-/I3- cyclic redox system for solar-electrocatalytic recovery of H2 and S from toxic H2S

Abstract

The abundant availability of toxic H2S in many industrial and natural resources and its low thermodynamic decomposition makes it a viable economic source for the production of environmentally clean fuel (H-2). Here, a highly efficient In2S3/AgIO3 photoanode and Pt/C-based waterproofed carbon fibre cathode were prepared for the recovery of H-2 and S from toxic H2S in a cyclic redox system of I-/I-3(-). The H2S was oxidized to S by I-3(-) in the photo-anode compartment and H+ was efficiently reduced to H-2 in the photocathode region. A maximum H-2 and S production rate of similar to 0.26 mmol h(-1) cm(-2) and similar to 0.23 mmol h(-1) cm(-2) were achieved, respectively and the photocurrent density of similar to 0.9 mA cm(-2) was attained during the entire operation. The In2S3/AgIO3 photoanode exhibited high energy conversion efficiency and polysulfides were not detected after the reaction, suggesting that the toxic H2S was completely converted into H-2 and S. The proposed system with I-/I-3(-) redox provides an energy-sustaining method for simultaneous treatment of toxic H2S and clean fuel production. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.