Reduced titania nanorods and Ni–Mo–S catalysts for photoelectrocatalytic water treatment and hydrogen production coupled with desalination

• Published in: Applied catalysis. B, Environmental Environmental, 2021-05, Vol.284, p.119745, Article 119745
• Main Authors: Kim, Seonghun, Han, Dong Suk, Park, Hyunwoong
• Format: Article
• Language: English
• Subjects: Anolytes; Brackish water; Brackish water desalination; Catalysts; Chlorine; Chlorine oxidation reaction; Decomposition reactions; Desalination; Electrocatalyst; Electrochemical analysis; Electrochemistry; Energy consumption; Hydrogen evolution reaction; Hydrogen production; Molybdenum; Molybdenum disulfide; Nanorods; Nickel; Photoelectrocatalyst; Physiochemistry; Substrates; Titanium dioxide; Urea; Water treatment
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.119745

[Display omitted] •A novel ternary hybrid photoelectrochemical process is presented.•Thermochemically reduced TiO2 nanorod arrays are developed for treatment of urea.•Ni-Mo-S composite electrocatalysts are developed for H2 production.•The photoanodic and cathodic processes are coupled with desalination.•The high efficiency ternary processes are achieved. This study presents a ternary hybrid solar desalination process coupled with photoelectrocatalytic water treatment and H2 production in a single device. The desalination of brackish water in the desalination cell is initiated via photoinduced charge generation with a thermochemically reduced TiO2 nanorod array photoanode. The chlorides transferred to the neighboring anolyte at ion-transport efficiency of ∼100% are photoelectrochemically transformed into reactive chlorine species responsible for the decomposition of urea into nitrate in the anolyte. Simultaneously, the H2 production with a Ni–Mo–S (Ni2S3/MoS2) composite catalyst grown onto porous Ni substrate is achieved at Faradaic efficiency of ∼90% in the catholyte concentrated with desalted Na+. Regardless of the operation condition, the H2 energy contributes to the reduction in the energy consumption for desalination by 25%–30%. The overall ternary hybrid process is understood systematically, and the physiochemical properties and electrochemical behavior of the Ni–Mo–S catalysts are examined.