Executive Summary : | Electrocatalytic oxygen reduction (ORR) catalysts can revolutionize energy conversion technologies, particularly in fuel cells and metal-air batteries. The selective two-electron reduction of ORR can be used for on-site H2O2 production, but the energy-intensive hydroquinone process with Pd as a catalyst is currently used for industrial scale H2O2 production. Researchers are exploring on-site methods to produce H2O2 on a large scale, with four-electron selective ORR to water being desirable for fuel cell and metal-air batteries. Efficient control of selectivity is crucial for both pathways to achieve target applications. New catalysts with higher activity, selectivity, and durability are needed, and recent studies suggest that the energetics of the M-OOH intermediate formed during the ORR process determine selectivity. Changing the coordination environment from conventional N4 to N4-xOx may significantly alter ORR selectivity. Graphene and hetero-atom doped graphene are widely used as catalyst supports for ORR. However, these systems are associated with metal leaching and have poor durability. New methods to generate M-N-C sites with enhanced durability can solve future energy crises and lead to efficient green methods for large-scale H2O2 production. This proposal proposes a versatile approach for synthesizing graphene-based composites consisting of M-N4, M-O4, and M-N4-xOx sites on graphene. The functionalization of graphene with nitrogen and oxygen-containing functionalities will enhance durability, and careful selection of synthetic routes will generate desired neighboring functionalities. The active sites generated by this approach are expected to be more flexible and durable for long-term applications. |