Oxide-supported metal single-atom catalysts have exhibited excellent catalytic performance for water gas shift (WGS) reaction.  Here, we report the single-atom catalyst (SAC) Pt₁/FeO_x exhibits excellent medium temperature catalytic performance for WGS reactions by the density functional theory (DFT) calculations and experimental results. The calculations indicate that H₂O molecules are easily dissociated at oxygen vacancies, and the formed OH* and O* are adsorbed on Pt₁ single atoms and the adjacent O atoms, respectively. After studying four possible reaction mechanisms, the optimal WGS reaction pathway is proceeded along the carboxyl mechanism (Pathway III), in which the formation of *COOH intermediates can promote the stability of Pt₁/FeO_x SAC and the occurrence of WGS reaction more easily. The energy barrier of the rate-determining step during the entire reaction cycle is only 1.16 eV, showing the high activity for the medium temperature WGS reaction on Pt₁/FeO_x SAC, which was verified by experimental results. Moreover, the calculated turn-over frequencies (TOF) of CO₂ and H₂ formation on Pt₁/FeO_x at 610 K (337 ℃) can reach up to 1.14´10^-3 s⁻¹ site⁻¹ through carboxyl mechanism. In this work, we further expand the application potential of Pt₁/FeO_x SAC in water gas shift (WGS) reaction.

Alcohol-based disinfectants have protected people in the coronavirus disease 2019 (COVID-19) pandemic, but olfactory stimuli of ethanol may evoke unpleasant memories associated with stressful situations in the devastating infectious disease. The smell of ethanol in household cleaning and disinfectant products can be covered up by the fragrance additives, and 3-hexenol is especially appreciated for the characteristic, strong odor of green plants. Industrial production of 3-hexenol relies on the selective hydrogenation of 3-hexyn-1-ol, where Lindlar catalyst is normally used for the superior selectivity. Although achieving such catalytic transformation in ethanol solution seems as a direct way to produce a disinfectant with green aroma, a popular consumer product in the post-COVID era, severe leaching of toxic Pb hinders Lindlar catalyst as a promising candidate. We find that the Fe₂O₃ supported Pd single-atom catalyst is highly selective to fulfill semi-hydrogenation of 3-hexyn-1-ol in 75% ethanol, and the aforementioned household product is readily generated after filtrating the stable, solid catalyst out of reaction solution. Single-atom catalysts have been frequently utilized for fine-chemical synthesis, while in this work they make stunning debut in practical manufacture of daily used products.

Gold-based catalysts are promising in CO preferential oxidation (CO-PROX) reaction in H₂-rich stream on account of their high intrinsic activity for CO elimination even at ambient temperature. However, the decrease of CO conversion at elevated temperature due to the competition of H₂ oxidation, together with the low stability of gold nanoparticles, has posed a dear challenge. Herein, we report that Au-Cu bimetallic catalyst prepared by galvanic replacement method shows a wide temperature window for CO total conversion (30–100 °C) and very good catalyst stability without deactivation in a 200-h test. Detailed characterizations combined with density functional theory (DFT) calculation reveal that the synergistic effect of Au-Cu, the electron transfer from Au to Cu, leads to not only strengthened chemisorption of CO but also weakened dissociation of H₂, both of which are helpful in inhibiting the competition of H₂ oxidation thus widening the temperature window for CO total conversion.

Selective hydrogenation of acetylene in excess ethylene is an important reaction in both fundamental study and practical application. Pd-based catalysts with high intrinsic activity are commonly employed, but usually suffer from low selectivity. Pd single-atom catalysts (SACs) usually exhibit outstanding ethylene selectivity due to the weak π-bonding ethylene adsorption. However, the preparation of high-loading and stable Pd SACs is still confronted with a great challenge. In this work, we report a simple strategy to fabricate Pd SACs by means of reducing conventional supported Pd catalysts at suitable temperatures to selectively encapsulate the co-existed Pd nanoparticles (NPs)/clusters. This is based on our new finding that single atoms only manifest strong metal–support interaction (SMSI) at higher reduction temperature than that of NPs/clusters. The derived Pd SACs (Pd₁/CeO₂ and Pd₁/α-Fe₂O₃) were applied to acetylene selective hydrogenation, exhibiting much improved ethylene selectivity and high stability. This work offers a promising way to develop stable Pd SACs easily.