Transforming C Molecules into Polyhedral Carbon Micro-Nano Shells for Electrochemically Producing HO in Neutral Electrolytes.

The electrochemical production of hydrogen peroxide (HO) via the two-electron oxygen reduction reaction (ORR) can realize the customer-oriented onsite synthesis of HO in a green and sustainable method. The ongoing challenge that needs to be solved is the fabrication of robust electrocatalysts of excellent performance. In this work, C was selected as a precursor due to its uniform structure and abundant pentagon rings. Thanks to the strong interaction between C and thiophene, after heteromolecule assembly in the liquid reaction and subsequent reconstruction of the carbon topological structure in solid calcination, C was successfully transformed into polyhedral carbon micro-nano shells (PCMNS) with an effective pore structure for the first time, which exhibited excellent capacity for production of HO via two-electron ORR, especially in neutral media. In addition to the high onset potential (0.49 V vs reversible hydrogen electrode (RHE)) and low Tafel slope (72 mV dec), its selectivity reached >90% within the potential range of 0.30-0.45 V and maintained >80% after constant potential electrolysis for 10 h. The yield rate of HO was 1102.5 mmol g h, determined by an H-type electrolytic cell, which was one of the highest values of metal-free carbon-based ORR electrocatalysts ever reported. Such excellent two-electron ORR performance of PCMNS was attributed to its abundant accessible active sites and hierarchical pore structures.