Interfacial Reduction Nucleation of Noble Metal Nanodots on Redox-Active Metal–Organic Frameworks for High-Efficiency Electrocatalytic Conversion of Nitrate to Ammonia

Abstract

Electrochemically converting nitrate to ammonia is a promising route to realize artificial nitrogen recycling. However, developing highly efficient electrocatalysts is an ongoing challenge. Herein, we report the construction of stable and redox-active zirconium metal−organic frameworks (Zr-MOFs) based on Zr 6 nanoclusters and redox-reversible tetrathiafulvalene (TTF) derivatives as inorganic nodes and organic linkers, respectively. The redox-active Zr-MOF can facilitate the in situ reduction of noble metal precursors free of external reductants and realize the uniform nucleation of noble metal nanodots (NDs) on Zr-MOF, achieving the preparation of M-NDs/Zr-MOF (M = Pd, Ag, or Au). The highly porous Zr-MOF with good conductivity can facilitate the mass transfer process. Among the M-NDs/Zr-MOF catalysts, Pd-NDs/Zr-MOF exhibits the highest electrocatalytic activity, delivering a NH 3 yield of 287.31 mmol•h −1 •g −1 cat . and a Faradaic efficiency of 58.1%. The proposed interfacial reduction nucleation strategy for anchoring M NDs on Zr-MOFs can be applied to other challenging energy conversion reactions.

Co-Doped Fe3S4 Nanoflowers for Boosting Electrocatalytic Nitrogen Fixation to Ammonia under Mild Conditions

“…Ammonia, one of the high-yield synthetic chemicals, plays an irreplaceable role in global agriculture and industry. − In industrial production, NH 3 is synthesized from N 2 and H 2 by the Haber Bosch process which leads to serious carbon dioxide emissions due to the inert molecular structure and an extremely strong triple bond energy (940.95 kJ mol –1 ) of the NN bond. − The electrochemical reduction provides an environmentally friendly and sustainable alternative method to the Haber–Bosch process for the synthesis of NH 3 . − The relatively highly efficient catalysts located at the top of the volcanic map, such as Rh, , Ru, , and Pd, , are the most commonly used in electrochemical nitrogen reduction reaction (NRR). However, the high prices of these noble metals limit the further development of electrocatalytic ammonia production.…”

Electrocatalytic nitrate reduction to ammonia via amorphous cobalt boride

“…S6-S9, ESI †) was used to quantify the concentration of ammonia, nitrite, hydrazine, and hydroxylamine in the post-test electrolyte. 16,39 As shown in Fig. 3b, the ammonia yield rates of CoB x and metallic Co gradually increased with decreasing applied potentials.…”

Electronic Metal–Support Interaction Triggering Interfacial Charge Polarization over CuPd/N‐Doped‐C Nanohybrids Drives Selectively Electrocatalytic Conversion of Nitrate to Ammonia

“…These features make NO 3 − an alternative nitrogen source for NH 3 synthesis with lower energy consumption than Haber-Bosch process. [11][12][13][14] As such, selective electrocatalytic reduction of NO 3 − to NH 3 under ambient operation conditions is a promising green avenue for achieving sustainable NH 3 production via detoxification and recycling of nitratecontaining wastewater. [15][16][17][18][19] A major challenge for selective electrocatalytic reduction of NO 3 − to NH 3 lies in the control of selectivity for target product because the electrochemical nitrate reduction reaction (NO 3 RR) is a complicated multi-electron-transfer process.…”

“…These features make NO 3 − an alternative nitrogen source for NH 3 synthesis with lower energy consumption than Haber–Bosch process. [ 11–14 ] As such, selective electrocatalytic reduction of NO 3 − to NH 3 under ambient operation conditions is a promising green avenue for achieving sustainable NH 3 production via detoxification and recycling of nitrate‐containing wastewater. [ 15–19 ]…”