Lei Ma

The design of efficient catalysts to mitigate SO₂ poisoning in low-temperature Selective Catalytic Reduction of NO_x (LT-SCR) is challenging. Herein, machine learning (ML) was employed to design catalysts with SO₂ resistance. A multidimensional data set containing 242 data points was constructed, including elemental descriptors, catalyst structures, reaction conditions, and SO₂ poisoning conditions. Regression models such as XGBoost (XGB) were trained to predict NO_x conversions and SO₂ resistance over different catalysts. It was found that the electronegativity descriptor (EN.) was the critical factor influencing NO_x conversions in the presence of SO₂, with approximately a monotonic positive correlation trend with NO_x conversions within the range of 0.7-0.8. Based on these findings, quaternary CeMoFe/Ti catalysts were further synthesized via an inverse design. It was observed that this catalyst could still maintain 60% NO_x conversion in the presence of SO₂ after 6 h at 250 °C, wherein the SO₂ resistance was significantly improved compared to ternary CeMo/Ti (∼40%) and binary Ce/Ti (∼4%) catalysts. In addition, the ML revealed the core roles of EN. in the design of SO₂ resistance catalysts, breaking through the limitations of traditional ternary catalyst systems. This study provided a data-driven paradigm for precise design of SO₂ resistance catalysts for the LT-SCR reaction, holding promise to accelerate the research and development of effective catalysts.

The electrochemical reduction of CO₂ to C₂H₄ offers a sustainable pathway to mitigate CO₂ emissions and produce valuable chemicals. However, developing stable electrocatalysts with high activity and C₂H₄ selectivity remains challenging. Herein, a tandem nanocatalyst, Ni_5wt%Cu(TA)₂, featuring closely adjacent Ni and Cu catalytic sites, has been identified as an exceptional and stable catalyst achieving a remarkable C₂H₄ Faradaic efficiency (FE) of 70.07% at a high current density of 211.43 mA cm^-2. In situ surface characterizations combined with theoretical calculations revealed that introducing Ni into the Cu(TA)₂ structure fulfilled three essential functions: (1) ensuring a steady *CO supply by efficiently converting CO₂, (2) facilitating *CO migration from Ni to adjacent Cu sites to establish a locally *CO-rich microenvironment, and (3) modulating the surface electronic structure to improve the ratio of Cu(I) active centers that favor C-C coupling. These synergistic effects promote the reduction of CO₂ toward the formation of C₂H₄. This study provides new insight into designing efficient tandem catalysts with *CO/Cu(I)-enriched local microenvironment for superior multicarbon electrosynthesis from CO₂RR.

Pt/CeO₂ ensemble catalysts are promising for propylene (C₃H₆) oxidation in vehicle exhaust, yet identifying the intrinsic active sites and understanding how the metal-support interface evolves at varying reaction temperatures remains contentious. Herein, we demonstrate that H₂-activated Pt/CeO₂ ensemble catalysts feature metallic Pt ensembles as intrinsic active sites, lowering the 50% conversion temperature by 120 °C after hydrogen activation. Various operando characterization techniques reveal an approximately 170 °C threshold temperature for the dynamic change of the reaction models. Meanwhile, kinetics and theoretical analysis illustrates that oxygen-facilitated dehydrogenation of sp ³ C-H bonds is the rate-determining step. At low temperatures, both C₃H₆ and O₂ adsorb and activate on metallic Pt, without CeO₂ involvement. Once the temperature exceeds threshold, C₃H₆ fully covers Pt sites, while O₂ activates over Pt-O-Ce interfaces and participates in dehydrogenation. This study highlights the dynamic nature of oxygen activation, leading to distinct reaction temperature regimes during C₃H₆ oxidation.

Ru-based catalysts have emerged as promising alternatives to HgCl₂ in vinyl chloride monomer (VCM) production by acetylene hydrochlorination. However, poor C₂H₂ activation and the generation of key intermediates (*CH₂═CH) have posed grand challenges for enhanced catalytic performances. Herein, we synthesized a Ni-intercalated Ru heterostructure using a lattice-strain engineering strategy, resulting in the desired electronic and chemical environments. The collaboration of Ni splits the adsorption centers of C₂H₂ and HCl by weakening the strong steric hindrance, and it also promotes the activation of the linear C≡C configurations. The well-controlled lattice strain enables strong d-d hybridization interactions between Ni and Ru, resulting in an upshift of the d-band center from -3.72 eV (for Ru/C) to -3.49 eV and electronic delocalization. This optimized local Ni-Ru/C structure thus enhances *H adsorption while weakening the energy barrier for generating *CH₂═CH intermediates. Furthermore, the energy barrier for VCM formation was simultaneously reduced. Accordingly, the Ni-Ru/C heterostructures achieve improved performance in pilot-scale trials, with a conversion of >99.2% and stability for over 500 h. These performances significantly surpass most reported Ru-based moieties and the traditional Hg catalysts, offering a promising avenue for C₂H₂ activation in industrial applications.

The elevation of the low-temperature oxidation activity for Pt/CeO₂ catalysts is challenging to meet the increasingly stringent requirements for effectively eliminating carbon monoxide (CO) from automobile exhaust. Although reducing activation is a facile strategy for boosting reactivity, past research has mainly concentrated on applying H₂ as the reductant, ignoring the reduction capabilities of CO itself, a prevalent component of automobile exhaust. Herein, atomically dispersed Pt/CeO₂ was fabricated and activated by CO, which could lower the 90% conversion temperature (T₉₀) by 256 °C and achieve a 20-fold higher CO consumption rate at 200 °C. The activated Pt/CeO₂ catalysts showed exceptional catalytic oxidation activity and robust hydrothermal stability under the simulated working conditions for gasoline or diesel exhausts. Characterization results illustrated that the CO activation triggered the formation of a large portion of Pt⁰ terrace sites, acting as inherent active sites for CO oxidation. Besides, CO activation weakened the Pt-O-Ce bond strength to generate a surface oxygen vacancy (V_o). It served as the oxygen reservoir to store the dissociated oxygen and convert it into active dioxygen intermediates. Conversely, H₂ activation failed to stimulate V_o, but triggered a deactivating transformation of the Pt nanocluster into inactive Pt_xO_y in the presence of oxygen. The present work offers coherent insight into the upsurging effect of CO activation on Pt/CeO₂, aiming to set up a valuable avenue in elevating the efficiency of eliminating CO, C₃H₆, and NH₃ from automobile exhaust.

Developing effective catalysts for N₂O decomposition at low temperatures is challenging. Herein, the Cs-O-Co structure, as the active species fabricated by single-layer atoms of Cs over pure Co₃O₄, originally exhibited great catalytic activity of N₂O decomposition in simulated vehicle exhaust and flue gas from nitric acid plants. A similar catalytic performance was also observed for Na, K, and Rb alkali metals over Co₃O₄ catalysts for N₂O decomposition, illustrating the prevalence of alkali-metal-promotion over Co₃O₄ in practical applications. The catalytic results indicated that the TOF of Co₃O₄ catalysts loaded by 4 wt% Cs was nearly 2 orders of magnitude higher than that of pure Co₃O₄ catalysts at 300 °C. Interestingly, the conversions of N₂O decomposition over Co₃O₄ catalysts doped by the same Cs loadings were significantly inhibited. Characterization results indicated that the primary active Cs-O-Co structure was formed by highly orbital hybridization between the Cs 6s and the O 2p orbital over the supported Co₃O₄ catalysts, where Cs could donate electrons to Co³⁺ and produce much more Co²⁺. In contrast, the doped Co₃O₄ catalysts were dominated by Cs₂O₂ species; meanwhile, CsOH species was generated by adsorbed water vapor led to a significant decrease in catalytic activity. In situ DRIFTS, rigorous kinetics, and DFT results elaborated the reaction mechanism of N₂O decomposition, where the direct decomposition of adsorbed N₂O was the kinetically relevant step over supported catalysts in the absence of O₂. Meanwhile, the assistance of adsorbed N₂O decomposition by activated oxygen was observed as the kinetically relevant step in the presence of O₂. The results may pave a promising path toward developing alkali-metal-promotion catalysts for efficient N₂O decomposition.

Resolving severe deactivation by alkali metals for selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) is challenging. Herein, surface Ce₂(SO₄)₃ species as a self-protection armor originally exhibited antipoisoning of potassium over ceria-based catalysts. The self-protection armor was also effective for other alkali (Na), alkali-earth (Ca), and heavy (Pb) metals, considerably resolving the deactivation of ceria-based SCR catalysts in practical applications. The catalytic activity tests indicated that the presence of ∼0.8 wt % potassium did not deactivate sulfated CeO₂ catalysts, yet commercial V₂O₅-WO₃/TiO₂ catalysts almost lost the NO_x conversions. Potassium preferably bonded with surface sulfates to form K₂SO₄ accompanied with the majority of surface Ce₂(SO₄)₃ over sulfated CeO₂ catalysts, but preferably coupled with active vanadia to generate inactive KVO₃ species over V₂O₅-WO₃/TiO₂ catalysts. Such an active Ce₂(SO₄)₃ species facilitated the adsorption and reactivity of NH₃ and NO_x, enabling ceria catalysts to maintain high catalytic efficiency in the presence of potassium. Conversely, the introduction of potassium into V₂O₅-WO₃/TiO₂ catalysts caused a considerable loss of surface acidity, hindering catalyst reactivity during the SCR reaction. The self-protection armor of Ce₂(SO₄)₃ species may open a promising pathway to develop efficient ceria-based SCR catalysts with strong antipoisoning ability.

Pt/CeO ₂ catalysts were most active in selective catalytic oxidation of ammonia, where Pt triggered the activation of surface lattice oxygen, and the dehydrogenation of ammonia assisted by surface lattice oxygen was the rate-determining step.