Congratulations to Maosong for his excellent work published on Small, highlighted as the front cover image. In this report, we demonstrate a facile in-situ xerogel (ISG) assisted synthetic strategy, using cheap materials, to construct Fe-N-C SACs (ISG Fe-N-C). The porous silica xerogel, formed in-situ with the Fe-N-C precursors, encourages the emergence of enormous micropores/mesopores and homogeneous confinement/protection to the precursors during pyrolysis, benefiting to the formation of abundant accessible active sites (27.6 × 10¹⁹ sites g^-1). Correspondingly, the ISG Fe-N-C exhibits excellent ORR activity with a half-wave potential (E_1/2=0.91 V) in alkaline medium. The Zn-air battery assembled using the ISG Fe-N-C SACs as the bifunctional catalyst of air cathode, demonstrates commendable performance with high peak power density of 249.1 mW cm^-2 and superior long-term stability (660 cycles with 220 h). This work offers an economic and efficient way to fabricate PGM-free SACs for diverse applications.

Please refer to: Small, 2022, 18, 202104934, https://doi.org/10.1002/smll.202104934