Fig. 1: Schematic illustration of catalyst preparation.

Preparation procedures for Fe SACs dominated by micropores (Fe SAs-MCP), mesopores (Fe SAs-MSP), and hierarchical pores of micropores and mesopores (Fe SAs-HP), respectively.
Preparation procedures for Fe SACs dominated by micropores (Fe SAs-MCP), mesopores (Fe SAs-MSP), and hierarchical pores of micropores and mesopores (Fe SAs-HP), respectively.