Embedding Ru Clusters and Single Atoms into Perovskite Oxide Boosts Nitrogen Fixation and Affords Ultrahigh Ammonia Yield Rate

Abstract

Ammonia (NH 3 ) is a key component in fertilizers, plastics, medicine, and many other chemical products. [1] Since 1908, the dominant method of industrial large-scale ammonia synthesis has been the Haber-Bosch process, which requires extreme conditions (temperature: 400-500 °C, pressure: 200-300 atm) and consumes a tremendous amount of energy (1% of total worldwide power consumption [2] ). Greenhouse gas emissions, the ineffective conversion rate of raw material, and complex and costly equipment maintenance have meant the unsustainability of the Haber-Bosch process. [2,3] Even high-efficiency ammonia production that was using potassium-hydride-intercalated graphite [4] at 250-400 °C and 1 MPa in a home-built, fixed-bed reactor also consumes considerable power. The clean-energy-driven ENRR is a potential candidate to replace Ammonia is a key chemical feedstock worldwide. Compared with the wellknown Haber-Bosch method, electrocatalytic nitrogen reduction reaction (ENRR) can eventually consume less energy and have less CO 2 emission. In this study, a plasma-enhanced chemical vapor deposition method is used to anchor transition metal element onto 2D conductive material. Among all attempts, Ru single-atom and Ru-cluster-embedded perovskite oxide are discovered with promising electrocatalysis performance for ENRR (NH 3 yield rate of up to 137.5 ± 5.8 µg h −1 mg cat −1 and Faradaic efficiency of unexpected 56.9 ± 4.1%), reaching the top record of Ru-based catalysts reported so far. In situ experiments and density functional theory calculations confirm that the existence of Ru clusters can regulate the electronic structure of Ru single atoms and decrease the energy barrier of the first hydrogenation step (*NN to *NNH). Anchoring Ru onto various 2D perovskite oxides (LaMO-Ru, MCr, Mn, Co, or Ni) also show boosted ENRR performance. Not only this study provides an unique strategy toward transition-metal-anchored new 2D conductive materials, but also paves the way for fundamental understanding the correlation between cluster-involved single-atom sites and catalytic performance.

Unraveling the Activity Trends and Design Principles of Single-Atom Catalysts for Nitrate Electrocatalytic Reduction

“…The NITRR is investigated by a standard three-electrode setup in an H-type electrolytic cell (Figure S6), which is widely used in N species reduction reactions. − Both colorimetric methods (Figure S7) and 1 H nuclear magnetic resonance (NMR) spectra (Figure S8) are performed to quantify NH 3 . We first screen the features of different SAs by analyzing their NITRR activities (Figure a), such as the Ga/NC, Mn/NC, Ru/NC, Ni/NC, Mo/NC, Pd/NC, Pt/NC, and Cu/NC, under the same experimental conditions, which contains 0.5 M Na 2 SO 4 solution (50 mL) and 200 ppm nitrate-N.…”

Electronic and Structural Engineering of Atomically Dispersed Isolated Single‐Atom and Alloy Architectures

“…[ 193 ] Perovskite oxides with embedded Ru clusters regulate the electronic structure of Ru single atoms, opening a new avenue for 2D conductive materials with cluster‐involved single atoms. [ 194 ] Both nanostructure and atomic‐level synergistic involvement were witnessed in the interconnected 3D hierarchically porous structure with Nb single‐atom modulation within a Co 3 O 4 nanocage. [ 195 ] Stable single‐atom Pt with high‐density active sites with the formation of surface peroxo species on CeO 2 film is known to favor the dense and uniform distribution.…”

Double–single-atom MoCu-embedded porous carbons boost the electrocatalytic N2 reduction reaction

“…[6][7][8] Due to limitations of the NH 3 yield rate and Faraday efficiency (FE), eNRR is, regrettably, still only at the laboratory development stage. 9,10 To address the industrialization of eNRR, innovative and rational electrocatalytic materials are being developed.…”