Reverse water gas shift reaction over CuFe/Al2O3 catalyst in solid oxide electrolysis cell

Abstract

Catalytic reduction by the reverse water gas shift (RWGS) reaction is an efficient way to utilize carbon dioxide and reduce its environmental impact as a greenhouse gas. In this research, an active CuFe/Al2O3 nano powder was developed as a high temperature reforming catalyst for the RWGS reaction. The powder was synthesized by a wet-impregnation method and the copper alloy was uniformly dispersed on the γ-Al2O3 support. At a gas space velocity of 60,000 h−1, the conversion of carbon dioxide was 42% at 700 °C, which is very close to the equilibrium conversion of 44%. The results indicated excellent reforming activity of the CuFe/Al2O3 catalyst for the high temperature RWGS reaction. In addition, the catalyst was applied in the form of a reforming layer over a conventional Ni-based electrode of a solid oxide electrolysis cell (SOEC) for an integrated SOEC-RWGS system. Hydrogen produced from steam electrolysis over the Ni-based cathode can be efficiently utilized to reduce the carbon dioxide by the RWGS reaction over the CuFe/Al2O3-based reforming layer. In this bilayer design, the reforming layer maintained the high surface area necessary for achieving good reforming activity, while the electrode layer possessed a high degree of sintering to enhance its electrochemical function. A high conversion of carbon dioxide (37% at 700 °C) was obtained in our bilayer SOEC-RWGS system. This promising result suggests the feasibility of the integrated SOEC-RWGS system for an efficient co-electrolysis device.