Manganese oxide nanocrystals embedded porous Graphene-like network for electrosynthesis of H2O2 and construction of Self-powered aptasensor

To improve the selectivity and production rate of the H2O2 electrosynthesis, an electrocatalyst was established based on ultrathin graphene-like mesoporous carbon nanosheets embedded with ultra-small manganese oxide (MnOx) nanocrystals (denoted as MnOx@C). A polymer-manganese-metal–organic framework (polyMn-MOF) was used as the precursor for the preparation of the series of MnOx@C hybrid by calcining at different temperature (600, 700, and 800 °C) under nitrogen atomsphere. Density functional theory simulation revealed that MnOx@C-700 obtained by pyrolyzing polyMn-MOF at 700 °C exhibited the optimization adsorption energy of *OOH, thus showing a high H2O2 selectivity of 96.5 % and large limited oxygen reduction current of 2.3 mA cm−2. Meanwhile a high mass activity of 35.56 A g−1 (at 0.4 V vs the reversible hydrogen electrode) and high durability over 10 h were attained for the MnOx@C-700 catalyst. Moreover, the MnOx@C-700-assembled Zn-air battery (ZAB) showed a large open-circuit voltage of 1.34 V and a remarkable peak power density of 2.22 mW cm−2. The constructed ZAB-driven self-powered aptasensor demonstrated a wide linear range of 0.1 pg mL−1–100 ng mL−1 and an ultralow detection limit of 0.08 pg mL−1 toward diethylstilbestrol. This work provided new insights onto the H2O2 electrosynthesis and detection of hazards using the self-powered biosensing strategy.