Solar hybrid photo-thermochemical sulfur-ammonia water-splitting cycle: Photocatalytic hydrogen production stage

Ekaterini Ch Vagia, Nazim Muradov, Agni Kalyva, Ali T-Raissi, Nan Qin, Arun R. Srinivasa, Konstantinos Kakosimos

Research output: Contribution to journalArticle

14 Citations (Scopus)


One of the main limitations of existing solar thermochemical water-splitting cycles (WSC) are that they utilize only thermal component of the solar irradiation neglecting its photonic component. A new hybrid photo-thermochemical sulfur–ammonia (HySA) WSC developed at the Florida Solar Energy Center allows circumventing this shortcoming. In the HySA cycle, water splitting occurs by means of solar beam splitting which enables utilization of the quantum (UV–Vis) portion of the solar spectrum in the hydrogen production stage and the thermal (IR) portion in the oxygen production stage. Present work investigates the photocatalytic hydrogen production step using narrow band gap CdS and CdS–ZnS composite photocatalysts, and ammonium sulfite as an electron donor. The choice of the electron donor was determined by the considerations of its regenerability in the thermal stages of the HySA cycle. This article examines the impact of photocatalyst and cocatalyst loading, temperature, and light intensity on hydrogen production rates. Photocatalysts, cocatalysts and photoreaction products were analyzed by a number of materials characterization (XRD, SEM, TEM, EDS) and analytical (GC and IC) methods. The experimental data obtained provide guidance for the improved solar photoreactor design.

Original languageEnglish
Pages (from-to)20608-20624
Number of pages17
JournalInternational Journal of Hydrogen Energy
Issue number32
Publication statusPublished - 10 Aug 2017



  • Cadmium sulfide
  • Cocatalyst
  • Hydrogen
  • Solar
  • Water splitting cycle
  • Zinc sulfide

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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