Semicrystalline Conjugated Polymers with Well‐Defined Active Sites for Nitrogen Fixation in a Seawater Electrolyte

Abstract

Faradaic efficiency for the nitrogen reduction reaction (NRR) is often limited by low N2 solubility in the electrolyte, while a large number of intimate contacts between the electrolyte and solid catalyst can also inevitably sacrifice many active sites for the NRR. Here, it is reported that a “quasi‐gas–solid” interface formed in donor–acceptor‐based conjugated polymers (CPs) is beneficial to boosting the NRR process and at the same time suppressing the competing hydrogen evolution reaction. Of particular interest, it is found that a semicrystalline CP catalyst, SC‐PBDT‐TT, exhibits a high Faradaic efficiency of up to 60.5% with a maximum NH3 production rate of 16.8 µg h−1 mg−1 in a neutral‐buffered seawater electrolyte. Molecular dynamics and COMSOL Multiphysics simulations reveal the origin of the observed high NRR performance arising from the presence of desirable crystal regions to resist the penetration of H2O molecules, leading to the formation of a “quasi‐gas–solid” interface inside the catalyst for a favorable direct‐contact between the catalyst and N2 molecules. Furthermore, high‐throughput computations, based on density functional theory, reveal the actual real active site for N2 adsorption and reduction in SC‐PBDT‐TT. This work provides a new framework for optimizing NRR performance of metal‐free catalysts by controlling their crystallinities.

Pre‐Adsorbed H‐Assisted N2 Activation on Single‐Atom Cadmium‐O5 Decorated In2O3 for Efficient NH3 Electrosynthesis

“…[ 2 ] However, this “gray ammonia” process is cost‐ and energy‐intensive consuming over 1% of the world's energy originating from fuel combustion, and produces ≈1.8% of global CO 2 emissions (≈300 million metric tons per year). [ 3–6 ] Therefore, it is important to develop effective and eco‐friendly routes for green NH 3 synthesis that directly use intermittent renewable energy sources (e.g., solar and wind) with zero carbon emissions and that demand less infrastructure and energy input. [ 7,8 ] To this end, electrochemical N 2 reduction powered by renewably generated electricity has recently sparked great research interest.…”

In situ growth of a GDY–MnOx heterointerface for selective and efficient ammonia production

“…[5][6][7] During the past few years, many efforts have been made to study the electrochemical nitrogen reduction reaction (NRR) for NH 3 synthesis with the purpose of replacing the traditional Haber-Bosch process. [8][9][10][11][12][13][14] But the low NH 3 yield rate (Y NH 3 ) and faradaic Efficiency (FE) of the reported NRR are still far from those required for practical applications due to the ultralow aqueous solubility of N 2 , the ultrahigh cleavage energy of NRN (941 kJ mol À1 ), and the serious competition with the hydrogen evolution reaction (HER). [15][16][17][18] Recently, the NtRR has shown great potential for efficient NH 3 synthesis due to the lower bond energy of the NQO bond and the higher solubility of NO 3 À as compared to the NRR.…”

Ultrasonic-assisted hydrothermal synthesis of RhCu alloy nanospheres for electrocatalytic urea production

“…26 Additionally, the by-product of NH 3 , NO 2 À , N 2 H 4 , and the residual NO 3 À were also detected by using the indophenol blue method (ESI, † Fig. S4), 27 spectrophotometric method (ESI, † Fig. S5), 28 Watt and Chrisp method (ESI, † Fig.…”