Efficient Non‐dissociative Activation of Dinitrogen to Ammonia over Lithium‐Promoted Ruthenium Nanoparticles at Low Pressure

Abstract

There is an exciting possibility to decentralize ammonia synthesis for fertilizer production or energy storage without carbon emission from H2 obtained from renewables at small units operated at lower pressure. However, no suitable catalyst has yet been developed. Ru catalysts are known to be promoted by heavier alkali dopants. Instead of using heavy alkali metals, Li is herein shown to give the highest rate through surface polarisation despite its poorest electron donating ability. This exceptional promotion rate makes Ru–Li catalysts suitable for ammonia synthesis, which outclasses industrial Fe counterparts by at least 195 fold. Akin to enzyme catalysis, it is for the first time shown that Ru–Li catalysts hydrogenate end‐on adsorbed N2 stabilized by Li+ on Ru terrace sites to ammonia in a stepwise manner, in contrast to typical N2 dissociation on stepped sites adopted by Ru–Cs counterparts, giving new insights in activating N2 by metallic catalysts.

Interstitial and substitutional light elements in transition metals for heterogeneous catalysis

“…Ruthenium is an effective catalyst for Haber–Bosch thermal ammonia synthesis from N 2 /H 2 . 125 Doping Ru with Li species has recently been shown by our research group 126 to confer the strongest promotion effect in comparison to other alkali and alkaline earth metal dopants ( Fig. 15a ).…”

Intercalating lithium into the lattice of silver nanoparticles boosts catalytic hydrogenation of carbon–oxygen bonds

“…Our previous work has detailed a method for the synthesis of a stable interstitial species such as smaller Li, B and C elements into Pd lattice after reduction at elevated temperature, which causes detectable Pd lattice expansion due to electron enrichment to Pd. [53][54][55][56] In contrast, we do not see significant change in Ag lattice for Li + doping, even after reduction at the same temperature, presumably the poor catalytic properties of Ag (see Fig. S7-S8 and Table S2; In order to estimate the degree of lithium ion filling in the interstitials within the Ag lattice, using rapid acquisition X-ray pair distribution function, it is possible to characterize the X-ray scattering atoms/ions patterns due to their unique positions of this lattice.…”

“…More recently, developments in fast-pixelated detectors and data processing have allowed to yield simultaneous ADF and phase imaging for detection of light element(s) in heavy elemental matrix. 55 Being a phase imaging technique, ptychography is highly sensitive to light elements such as B since we have previously demonstrated to directly image B from Pd metal framework, [55][56][57] and is therefore applicable to this system. This is clearly shown in the supplementary information (Fig.…”

Recent Progress on Electrocatalytic Synthesis of Ammonia Under Amibent Conditions

“…对于热催化反应而言, Fe 基催化剂活性中心是由 7 个相邻的 Fe 原子组成(C7 位) [28] , 活性仅与 C7 [29] 数量有 关, 且 Fe 基催化剂只有在高压条件下才能表现出良好 的活性 [30] . [35] .…”