Designing reactive bridging O2– at the atomic Cu-O-Fe site for selective NH3 oxidation

DOI: 10.1021/acscatal.2c04863

Authors: Xuze Guan (University College London) , Rong Han (Wuhan University) , Hiroyuki Asakura (Kindai University; Kyoto University) , Zhipeng Wang (University College London) , Siyuan Xu (Wuhan University) , Bolun Wang (University College London) , Liqun Kang (University College London) , Yiyun Liu (University College London) , Sushila Marlow (University College London) , Tsunehiro Tanaka (Kyoto University) , Yuzheng Guo (Wuhan University) , Feng Ryan Wang (University College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Catalysis

State: Published (Approved)
Published: November 2022
Diamond Proposal Number(s): 23759 , 24450 , 29094 , 24197

Abstract: Surface oxidation chemistry involves the formation and breaking of metal–oxygen (M–O) bonds. Ideally, the M–O bonding strength determines the rate of oxygen absorption and dissociation. Here, we design reactive bridging O2– species within the atomic Cu–O–Fe site to accelerate such oxidation chemistry. Using in situ X-ray absorption spectroscopy at the O K-edge and density functional theory calculations, it is found that such bridging O2– has a lower antibonding orbital energy and thus weaker Cu–O/Fe–O strength. In selective NH3 oxidation, the weak Cu–O/Fe–O bond enables fast Cu redox for NH3 conversion and direct NO adsorption via Cu–O–NO to promote N–N coupling toward N2. As a result, 99% N2 selectivity at 100% conversion is achieved at 573 K, exceeding most of the reported results. This result suggests the importance to design, determine, and utilize the unique features of bridging O2– in catalysis.

Journal Keywords: reactive O2−; oxidation chemistry; heterogeneous catalysis; NH3; emission control, single-atom catalyst

Subject Areas: Chemistry

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS , B18-Core EXAFS , E01-JEM ARM 200CF

Other Facilities: P64 at PETRA III; SPring-8; ISISS at BESSY II

Added On: 05/12/2022 09:25

Documents:
acscatal.2c04863.pdf

Discipline Tags:

Physical Chemistry Catalysis Chemistry

Technical Tags:

Microscopy Spectroscopy Electron Microscopy (EM) X-ray Absorption Spectroscopy (XAS) Extended X-ray Absorption Fine Structure (EXAFS) X-ray Absorption Near Edge Structure (XANES) Scanning Transmission Electron Microscopy (STEM)