Pursuing both high catalytic performance and low cost is the key to developing applicable electrocatalysts for oxygen reduction reaction (ORR). In this work, we developed Fe single atom-doped on sulfur and nitrogen co-doped carbon catalysts (Fe₁/SCN-cm) using canola (Brassica napus L.) meal as the precursors, which show high catalytic performance in ORR with the half-wave potential as high as 0.92 V. Notably, Fe₁/SCN-cm also presents a high stability with only a 13 mV decrease after 10,000 cycle tests. The sulfur directly derived from canola (Brassica napus L.) meal and the porous structure with high surface area are the key to the high catalytic performance of Fe₁/SCN-cm. It is believed that this work provides a new arsenal for the synthesis of metal single atom catalysts and directions for the valorisation of canola meal.

The development of thermodynamically controllable synthetic strategy to manipulate the morphology of ZIF-8 without capping agent is essential to help understanding their facet effect and the structure-activity relationship of single atom catalysts derived from ZIF-8. Here, we prepared ZIF-8 with different morphologies (cube, truncated rhombododecahedral and rhombododecahedral) and thus area ratio of exposed {100}, {110} facets by a thermodynamically controllable synthetic strategy. When the reaction proceeds under room temperature (30 °C), the assembling of ZIF-8 followed an area-reducing layered growth mode, while switched to an integral layered growth mode at lower temperature –40 °C. Moreover, this strategy also works to obtain ZIF-8 encapsulated with metal precursors (Fe(acac)₃, Cu(acac)₂ and Co(acac)₂). Single Fe atom anchored on nitrogen doped carbon catalysts (SA-Fe/CN) derived from Fe-ZIF-8 retain their original morphologies and the unsaturated surface-active sites on {100} facet, which further displays different catalytic performance towards oxygen reduction reaction (ORR). This work not only reveals the different growth pattern of ZIF-8, but also points out a new direction for designing and synthesizing MOFs with different morphology rationally.