Synergistic Catalysis of Co–P1N3 Single Atoms and Co Clusters for Boosting Electrosynthesis of Hydrogen Peroxide in Acidic Medium

Electrocatalytic two-electron oxygen reduction reaction (2e – ORR) in an acidic medium is a promising strategy to produce hydrogen peroxide (H 2 O 2 ), but its practical application is restricted by the lack of low-cost and efficient electrocatalysts. Here, we design and construct a catalyst of single Co atoms (Co SA ) coordinated with one P atom and three N atoms (Co–P 1 N 3 ) and Co nanoclusters (Co Clu ) coloaded onto porous N,P-doped carbon matrix (Co Clu @Co SA -NPC) for selective electrocatalytic 2e – ORR-to-H 2 O 2 in an acidic environment. The Co Clu @Co SA -NPC demonstrates a high H 2 O 2 Faradaic efficiency (FE) of 98.3% with a H 2 O 2 yield rate of 273 mmol g cat –1 h –1 at 0.3 V versus the reversible hydrogen electrode (vs RHE). Meanwhile, it maintains a long-term durability for 300 h with a H 2 O 2 FE of above 90% at 0.3 V vs RHE in both H-cell and flow cell. At an industrialized current density of 250 mA cm –2, it can operate stably for 200 h with a cumulative H 2 O 2 yield of 22.81 g cm –2 . Experimental characterizations and theoretical calculations reveal that Co sites within Co Clu with an optimized electronic configuration are the active centers, which are activated by the asymmetrical Co–P 1 N 3 sites via their synergistic effect. The moderate adsorption strength for the *OOH intermediate of Co Clu leads to a thermodynamically favorable adsorption free energy of the *OOH intermediate, thus enhancing the 2e – ORR-to-H 2 O 2 performance of Co Clu @Co SA -NPC.