Alternative Strategies Toward Sustainable Ammonia Synthesis

Abstract

As one of the world's most produced chemicals, ammonia (NH 3 ) is synthesized by Haber-Bosch process. This century-old industry nourishes billions of people and promotes social and economic development. In the meantime, 3%-5% of the world's natural gas and 1%-2% of the world's energy reserves are consumed, releasing millions of tons of carbon dioxide annually to the atmosphere. The urgency of replacing fossil fuels and mitigating climate change motivates us to progress toward more sustainable methods for N 2 reduction reaction based on clean energy. Herein, we overview the emerging advancement for sustainable N 2 fixation under mild conditions, which include electrochemical, photo-, plasma-enabled and homogeneous molecular NH 3 productions. We focus on NH 3 generation by electrocatalysts and photocatalysts. We clarify the features and progress of each kind of NH 3 synthesis process and provide promising strategies to further promote sustainable ammonia production and construct state-of-the-art catalytic systems.

Towards understanding of electrolyte degradation in lithium-mediated non-aqueous electrochemical ammonia synthesis with gas chromatography-mass spectrometry

“…Lithium-mediated electrochemical ammonia synthesis (LiMEAS) is a promising alternative to the traditional complex thermochemical Haber-Bosch process, [1][2][3][4][5] which predominantly requires high temperatures (400-500 C) and pressures (150-200 bar) coupled with a steam reforming plant for hydrogen (H 2 ) production. 6 On the other hand, the LiMEAS is thermodynamically driven by an electrical potential instead of high temperatures and pressures, and the chemical reactivity of lithium towards nitrogen gas (N 2 ).…”

Optimization Strategies for Selective CO2 Electroreduction to Fuels

“…It was further confirmed by in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), which detected *OCH 3 and *OCH 2 species. Atomically dispersed transition metals supported on NC have been exploited as promising nonprecious electrocatalysts for converting CO 2 to CO, in which nitrogen-coordinated single-atom metal (M − N x ) moieties serve as the active sites [35,36,[74][75][76]. Zheng et al [74] developed a facile method to prepare Ni SAC catalysts on [65].…”

The chemical sciences and the quest for sustainability

“…Examples include the creation of new materials for trapping sunlight and for photochemical and electrochemical cleavage of water to generate H 2 as a potential non-carbon fuel; 33) advances towards artificial photosynthesis; 34) new developments in batteries; 35) and CO 2 fixation 36) reaction of H 2 with N 2 under more environmentally benign conditions than the Haber-Bosch process to produce NH 3 . 37) These areas illustrate that it is critically important for chemists to engage in work related to sustainable development, and for those doing so to develop competence in both cross-disciplinary working and systems thinking. As an example, a recent review noted that the massive amounts of clean water needed if NH 3 is to be the source of molecular hydrogen in a decarbonised energy economy may add substantially to water stress on a planetary scale unless there is sufficient supportive infrastructure.…”