Modulation of the Coordination Environment of Graphene-Loaded NiFe-LDH and PbO2 Catalysts by Plasma for Oxygen Evolution Reaction

The generation of hydrogen through water electrolysis represents a significant advancement in the transition towards low-carbon energy systems. Graphene-supported catalysts have demonstrated significant potential in improving the oxygen evolution reaction (OER) among several electrocatalysts utilised for this process. Nonetheless, attaining exact control over the morphology and electrical configuration of these catalysts continues to pose a considerable difficulty. This study presents the development of a highly effective electrocatalyst composed of graphene-supported NiFe LDH and PbO2, incorporating sulphur anions into the structure by a plasma jet treatment method. By optimising the ratio of sulphur anions, we were able to fine-tune the local coordination environment, which effectively adjusted the properties of the OH and OOH intermediates, thereby improving the OER catalytic performance. The plasma treatment introduced vacancy defects into the catalyst, further regulating its surface morphology and electronic structure. After sulphur anion optimisation, the graphene-supported catalyst exhibited excellent electrocatalytic performance in alkaline environments, achieving an OER overpotential of 228 mV at 100 mA·cm−2. This performance, along with exceptional stability, exceeds the majority of previously documented catalysts. The results underscore the promise of sulphur anion optimisation and plasma treatment in improving OER performance, providing significant insights for the advancement of highly effective water-splitting catalysts.