Hydrogen production via solar driven thermochemical cerium oxide-cerium sulfate water splitting cycle

Abstract

Production of H2 via water splitting reaction driven by concentrated solar power is one of the promising ways to fulfill the future energy demand. In this investigation, the cerium oxide-cerium sulfate H2O splitting (WS) cycle was thermodynamically analyzed and the obtained outcomes were compared with the formerly researched WS cycles. The thermodynamic calculations associated with the efficiency analysis were carried out by using HSC Chemistry thermodynamic software. The equilibrium compositions allied with the thermal reduction (TR) and WS steps were identified. The effect of molar flow rate of inert Ar (n Ar) on the temperature desirable for the ample dissociation of cerium sulfate was explored. Additionally, the influence of TR (TH) and WS temperatures (TL) on the sum of solar energy necessary to drive the process, re-radiation losses, quantity of energy that can be recuperated and the solar to fuel of the cycle was analyzed. The maximum solar to fuel (45.1%) for the cerium oxide - cerium sulfate WS cycle was achieved when the TR and WS steps were carried out at 1485 K and 650 K, respectively. The solar to fuel was further enhanced up to 53.1% by re-utilizing 30% of the heat recuperated from the cycle.