A plasma bombing strategy to synthesize high-loading single-atom catalysts for oxygen reduction reaction

Single-atom catalysts (SACs) have attracted tremendous attention owing to their unique intrinsic properties, while the facile synthesis, especially the direct transformation of metal salts into single-metal atoms, is still a huge challenge. Here we report a practical approach to access the large-scale synthesis of SACs, in which the metal salts are excited and stripped as mobile single-metal atoms flow under the "plasma bombing" treatment. Simultaneously, they are trapped and anchored by the defective and nitrogenous sites of the supports. More importantly, the synthesis approach is quite general, and it can be extended to the fabrication of various SACs. As an illustration, the prepared SAC-Fe/NC delivers a remarkable oxygen reduction reaction (ORR) performance. In combination with the theoretical analysis, an adsorbent-induced spin-crossover ORR mechanism is proposed, and the Fe species coordination with four pyridinic-type N atoms is demonstrated as the main contributor to the high performance of the prepared SAC-Fe/NC.