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

•MnOx nanocrystals, porous graphene-like network, polymer-metal–organic framework.•Homogeneously distributed catalytic sites, plenty of oxygen vacancies.•Selective H2O2 production via 2e- oxygen reduction reaction (96.5%).•Zn-air battery driven self-powered aptasensor, detection of diethylstilbestrol.•Detection limit of 0.08 pg mL−1, linear range of 0.1 pg mL−1-100 ng mL−1.