Sulfur-modified charge-asymmetry FeNi nanoalloy catalysts anchored on N-doped carbon nanosheets for efficient electrochemical CO2 reduction.

The electrochemical carbon dioxide reduction reaction (CO2RR) plays a crucial role in mitigating global CO2 emissions and achieving carbon neutrality. In this study, we present a sulfur-doped FeNi alloy on a nitrogen-doped carbon substrate (FeNi Alloy/SNC) as a highly active CO2RR catalyst. This advanced charge-asymmetric nanocluster catalyst features sulfur-doped Fe-Ni bimetallic sites. X-ray absorption spectroscopy (XAS) was used to verify the presence of these S-doped asymmetric bimetallic sites. The charge-asymmetric catalysts exhibited 98.1% CO conversion efficiency, which significantly surpassed that of S-containing Fe cluster/SNC, Ni cluster/SNC, and S-free FeNi/NC, Ni/NC, and Fe/NC catalysts. Furthermore, in situ synchrotron radiation XAS analysis revealed that the S-doped Fe-Ni bimetallic sites enhanced charge transfer between the metal centers, thereby facilitating the accelerated production of CO.