High-Performance Ni–Fe Redox Catalysts for Selective CH4 to Syngas Conversion via Chemical Looping

In traditional steam reforming of CH4, the CH4 conversion and its selectivity to CO and H2 are thermodynamically limited. In this work, we designed a series of Ni–Fe redox catalysts with varying Ni/Fe ratios. The Ni–Fe redox catalysts could function as oxygen carriers to selectively convert CH4 to syngas via chemical looping. The selectivity to CO was dramatically enhanced via a selective conversion route of CH4 to C and H2 in the reduction, followed by C gasification to syngas with hot steam. Taking the advantages of the highly reactive Ni species for CH4 activation and Fe species for water splitting, together with the resulting NiFe alloy in the reduced catalyst for catalytic CH4 decomposition, high CH4 conversion up to 97.5% and CO selectivity up to 92.9% were achieved at 900 °C with productivity of CO and H2 of 9.6 and 29.0 mol kgcatalyst–1, respectively, on equimolar Ni–Fe catalyst.