Abstract
Single-atom catalysts have recently been applied in many applications such as CO oxidation. Experimental in situ investigations into this reaction, however, are limited. Hereby, we present a suite of operando/in situ spectroscopic experiments for structurally well-defined atomically dispersed Rh on phosphotungstic acid during CO oxidation. The identification of several key intermediates and the steady-state catalyst structure indicate that the reactions follow an unconventional Mars-van Krevelen mechanism and that the activation of O 2 is rate-limiting. In situ XPS confirms the contribution of the heteropoly acid support while in situ DRIFT spectroscopy consolidates the oxidation state and CO adsorption of Rh. As such, direct observation of three key components, i.e., metal center, support and substrate, is achieved, providing a clearer picture on CO oxidation on atomically dispersed Rh sites. The obtained information are used to engineer structurally similar catalysts that exhibit T 20 values up to 130 °C below the previously reported Rh 1 /NPTA.
| Original language | English |
|---|---|
| Article number | 1330 |
| Journal | Nature Communications |
| Volume | 10 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2019 |
Funding
We thank the NUS Flagship Green Energy Programme for the financial support. XAS measurements were performed at public XAS beamlines, BL01B1 and BL14B2, SPring-8 (Japan Synchrotron Radiation Research Institute, Hyogo, Japan) under the approval of JASRI (Proposal No. 2017A1256 & 2018B0949). W.C. acknowledges the funding support from National Natural Science Foundation of China (NSFC 91645102), Singapore National Research Foundation under the grant of NRF2017NRF-NSFC001–007. P.Z. thanks NSERC Canada for financial support. Z.W. was supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.