 The redox dynamics of sulfur with Ni/GDC anode during solid oxide fuel cell (SOFC) operation at mid- and low-range temperatures in an operando S K-edge XANES have been studied.Ni is a typical catalyst material for the anode in high temperature SOFCs.The operando spectro-electrochemical cell for this high temperature gas-solid reaction study under electrochemical conditions was based on a typical high temperature heterogeneous catalysis cell, which was further equipped with electric terminals.