Energy Decarbonization via Green H₂ or NH₃?

Abstract

The production of hydrogen from hydrocarbon/water compounds can be classified into three categories, namely "brown", "blue", and "green". 27 Brown hydrogen is produced from H 2 O by steam reforming of natural gas (or coal) at about 800−900 °C. The enthalpy required for H 2 production is significantly Figure 4. (a) Schematic diagram of (A) methane-fed and (B) electrolysis-driven Haber−Bosch ammonia production. Reproduced with permission from ref 44. Copyright 2020 The Royal Society of Chemistry. (b) Dissociative pathway for N 2 activation (above) and stepwise nondissociative pathway for N 2 activation (below). Reprinted with permission from ref 46. Copyright 2019 John Wiley and Sons. (c−e) Various strategies to carry out ammonia synthesis at low temperature and low pressure: (c) The use of electrostatically polar surfaces to alleviate hydrogen poisoning challenges at low temperature. Reprinted with permission from ref 52. Copyright 2020 American Chemical Society. (d) Dual-site mechanism to tackle nitrogen activation and hydrogen dissociation separately. Reprinted with permission from ref 54. Copyright 2020 Springer Nature. (e) Li-polarized surface to stabilize intermediates to carry out the more energy favorable non-dissociative pathway. Reprinted with permission from ref 46. Copyright 2019 John Wiley and Sons. (f) A novel mechanochemical method to enable ammonia synthesis at 45 °C and 1 bar. Reprinted with permission from ref 55. Copyright 2020 Springer Nature. (g) Direct eNRR via absorption of N 2 onto the catalyst surface, followed by progressive proton and electron additions to produce a first, followed by a second molecule of ammonia. Reprinted with permission from ref 56. Copyright 2018 John Wiley and Sons. (h) Indirect electrochemical N 2 reduction to ammonia based on lithium as a mediator, forming Li 3 N as an intermediate, and reaction with H 2 O on a copper substrate. Reprinted with permission from ref 57.

Highly Active and Stable NiCuMo Electrocatalyst Supported on 304 Stainless Steel Porous Transport Layer for Hydrogen Evolution in Alkaline Water Electrolyzer

“…Renewable energy storage became more and more critical in the path for a decarbonized society. [1][2][3] A way to store renewable electrical energy is producing fuels and chemicals that do not suffer of self-discharge phenomena. In this context, producing (and storing) green hydrogen is the key of the so called "hydrogen economy" and can be achieved through the electrochemical water-splitting process that produces hydrogen and oxygen at cathode and anode electrodes, respectively.…”

Multidirectional Solvent-Induced Structural Transformation in Designing a Series of Polycatenated Cobalt(II) Coordination Polymers: Impact on Carbon Dioxide and Hydrogen Uptake

“…The use of conventional fossil fuels stands at the nook of question mark nowadays, due to its limited sources as well as detrimental polluting issues related to the release of greenhouse gases . The time-tested answers to the aforesaid problem are based on two aspects: one is the scavenging of greenhouse gases if there is no way other than the use of fossil fuels; the other sustainable solution is the use of environment-friendly green energy sources where the hydrogen fuel is considered as “ Holy Grail .” Over the decades, scientific communities have painstakingly involved in green hydrogen production and high-density storage for onboard use as fuel . In this present context, several synthetically designed coordination polymers (CPs), − covalent organic framework (COF), , and so forth have come out as promising tools for hydrogen storage devices and hence explored extensively.…”

Mixed oxygen ionic‐carbonate ionic conductor membrane reactor for coupling CO2 capture with in situ methanation

“…Since H 2 is difficult to store and transport, it has been suggested to be further converted to CH 4 through the methanation process. The produced CH 4 can be incorporated into the existing natural gas network and as the primary raw material of the existing chemical system 15–18 . This technical route can realize the conversion of renewable energy to chemical energy, named as power to gas (PtG), which will help to build a low‐carbon new energy system in the future.…”

“…The produced CH 4 can be incorporated into the existing natural gas network and as the primary raw material of the existing chemical system. [15][16][17][18] This technical route can realize the conversion of renewable energy to chemical energy, named as power to gas (PtG), which will help to build a low-carbon new energy system in the future. Therefore, the CO 2 methanation is one of the core steps of SNG production and PtG processes.…”