2D Al-MOF with ultrathin nanoflake-assembled hollow microstructures for electrochemical hydrogen peroxide production.

• Ultrathin 2D Al-MOF nanosheets were synthesized by a solvothermal method. • The presence of a mixed solvent and sulfate ion is critical to the formation of the specific 2D Al-MOF. • Ther ultrathin morphology is beneficial for the exposure of active sites and mass/electron transport. • The optimized Al-MOF exhibited high catalytic activity with almost no overpotential and high selectivity for 2e− ORR to H 2 O 2. Electrochemical transformation from oxygen reduction reaction (ORR) to hydrogen peroxide (H 2 O 2) is one of the promising green techniques to synthesis H 2 O 2. However, due to the competing two processes of 2e− and 4e−ORR with different products, designing and synthesizing highly selective and active 2e− ORR electrocatalysts for H 2 O 2 production is fundamentally and practically important. In this work, we used a simple solvothermal method and self-template strategy to create ultrathin 2D Al-MOF nanosheets for efficient electrocatalytic synthesis of H 2 O 2 by 2e− ORR. The presence of a mixed solvent and sulfate ion is critical to the formation of the specific structure. Naturally, their ultrathin morphology and abundant mesoporous formation leads to the sufficient exposure of electrochemically active sites and high mass/electron transfer capability. Therefore, the Al-MOF NSs show excellent electrocatalytic performance for 2e− ORR. The optimized Al-MOF NSs-1 exhibited the best ORR catalytic performance with almost no overpotential and high selectivity for 2e− ORR to H 2 O 2 (94 %–98 %) in a wide range of low potentials in alkaline electrolyte. Meanwhile, the high reaction rate of 2.56 molg cat −1h−1 for H 2 O 2 production has also been achieved at 0.6 V. Furthermore, the Al-MOF NSs-1 enable to catalyze H 2 O 2 production with excellent durability and selectivity after long-term stability test (10,000 cycles) and 11 h of potentiostatic electrolysis. The present study indicates the promising application of metal organic frameworks (MOFs) materials in H 2 O 2 electrochemical synthesis. [Display omitted] [ABSTRACT FROM AUTHOR]