In Situ Exsolved Ni Nanoparticles From Pr 0.5 Sr 0.5 Ti 0.5 Mn 0.5 O 3 with Varying Ni Doping Levels for Direct Methane Solid Oxide Fuel Cells

ABSTRACT Methane (CH 4 ), with abundant reserves and mature infrastructure, is an attractive fuel for solid oxide fuel cells (SOFCs). In this work, the effects of Ni doping on the electrochemical performance of Pr 0.5 Sr 0.5 Ti 0.5 Mn 0.5 O 3 (PSTM)‐based anodes were investigated using Pr 0.5 Sr 0.5 Ti 0.5 Mn 0.4 Ni 0.1 O 3 (PSTMN41) and Pr 0.5 Sr 0.5 Ti 0.5 Mn 0.5 Ni 0.1 O 3 (PSTMN51). Ni incorporation and subsequent H 2 reduction generated highly dispersed Ni nanoparticles and abundant oxygen vacancies, enhancing electron transport and methane conversion. PSTMN41 exhibited superior catalytic activity and stability compared to PSTMN51 in humidified CH 4 . The PSTMN41‐based cells achieved peak power densities of 119.6 and 60.7 mW·cm − 2 under H 2 and humidified CH 4 at 850°C, with polarization resistances of 1.7 and 2.44 Ω·cm 2 . Moreover, PSTMN41 maintained excellent stability over 120 h continuous operation in humidified CH 4 . These results demonstrate that PSTMN41, featuring Ni nanoparticles and high oxygen vacancy concentration, is a promising anode material for SOFCs.