{'fraction_non_alphanumeric': 0.015527950310559006, 'fraction_numerical': 0.004968944099378882, 'mean_word_length': 5.884615384615385, '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}}
Homogeneous electrocatalytic oxidation of ammonia to N2 under mild conditions

Significance Water oxidation fixes carbon dioxide producing ∼100 gigatons (GT) of carbohydrates annually. Living organisms convert the stored chemical energy back to carbon dioxide and water through respiration. An analogous cycle can be envisioned whereby hydrogen gas is stored as ammonia, synthesized from atmospherically ubiquitous dinitrogen. Biological and industrial reduction of dinitrogen is currently estimated to produce 0.3–0.5 GT of ammonia annually. An important reaction in such a proposed nitrogen-based hydrogen storage and distribution scheme is the oxidation of ammonia back to dinitrogen and the protons and electrons that regenerate hydrogen gas. While inorganic materials can oxidize ammonia to dinitrogen, protons, and electrons, no molecular species are known to catalyze this reaction. We report that ruthenium polypyridyl complexes can catalyze ammonia oxidation to dinitrogen at room temperature and ambient pressure. During bulk electrolysis experiments, gas chromatography and mass spectrometry analysis of the headspace in the electrochemical cell showed that dinitrogen and dihydrogen are generated from ammonia with high faradaic efficiencies. A proposed mechanism where a hydrazine complex is the initial N–N bonded intermediate is supported by chemical and electrochemical experiments. This is a well-defined system for homogeneous electrocatalytic ammonia oxidation. It establishes a platform for answering mechanistic questions relevant to using ammonia to store and distribute renewable energy.