{'fraction_non_alphanumeric': 0.03913405495420483, 'fraction_numerical': 0.02164862614487927, 'mean_word_length': 5.070707070707071, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Synthesis Metal-free Nitrogen-doped Porous Carbon by Removing Al from Al-MOFs as an Efficient Electrocatalyst for Oxygen Reduction Reaction

Exploring cheap and stable electrocatalyst for the oxygen reduction reaction (ORR) is now an important issue for the large-scale application of fuel cells. Herein, we have demonstrated a facile synthesis of Nitrogen-doped porous carbons (NPC-MILs) for oxygen reduction reaction by using an amine functionalized Al-MOFs (NH 2 -MIL-53(Al)) as the precursor with both nitrogen source and carbon source. NPC-MILs as metal-free electrocatalysts are demonstrated promising potential for ORR. The optimized NPC-MIL-900 (carbonized at 900 °C) exhibits a likeness four-electron process and its ORR catalytic activity can be comparable to commercial Pt/C. Furthermore, chronoamperometric measurement shows that only 13% loss at the current density is occurred after 40000 s, whereas the corresponding current density loss at the Pt/C (20wt%) is as high as 31%. Chronoamperometric responses also show the NPC-MIL-900 catalyst has higher resistance to methanol in alkaline electrolyte than Pt/C. Those indicate that the NPC-MIL-900 has potential application in fuel cells.