Selective catalytic reduction of NO by CO is challenging in environmental catalysis but attractive owing to the advantage of simultaneous elimination of NO and CO. Here, model catalysts consisting of Pd nanoparticles (NPs) and single-atom Pd supported on a CeO₂ (111) film grown on Cu (111) (denoted as Pd NPs/CeO₂ and Pd₁/CeO₂, respectively) were successfully prepared and characterized by synchrotron radiation photoemission spectroscopy (SRPES) and infrared reflection absorption spectroscopy (IRAS). The NO + CO adsorption/reaction on the Pd₁/CeO₂ and Pd NPs/CeO₂ catalysts were carefully investigated using SRPES, temperature-programmed desorption (TPD), and IRAS. It is found that the reaction products on both model catalysts are in good agreement with those on real catalysts, demonstrating the good reliability of using these model catalysts to study the reaction mechanism of the NO + CO reaction. On the Pd NPs/CeO₂ surface, N₂ is formed by the combination of atomic N coming from the dissociation of NO on Pd NPs at higher temperatures. N₂O formation occurs probably via chemisorbed NO combined with atomic N on the surface. While on the single-atom Pd₁/CeO₂ surface, no N₂O is detected. The 100% N₂ selectivity may stem from the formation of O-N-N-O* intermediate on the surface. Through this study, direct experimental evidence for the reaction mechanisms of the NO + CO reaction is provided, which supports the previous density functional theory (DFT) calculations.

Ammonia borane (AB) is regarded as a promising chemical hydrogen-storage material due to its high hydrogen content, non-toxicity, and long-term stability under ambient temperature. However, constructing advanced catalysts to further promote the hydrogen production still remains a challenge for the hydrolysis of AB. Herein, we report a novel oxygen modified CoP₂ (O-CoP₂) material with dispersed palladium nanoparticles (Pd NPs) as a highly efficient and sustainable catalyst for AB hydrolysis. The modification of oxygen could optimize the catalytic synergy effect between CoP₂ and Pd NPs, achieving enhanced catalytic activity with a turnover frequency (TOF) number of 532 min⁻¹ and an activation energy (E_a) value of 16.79 kJ·mol⁻¹. Meanwhile, reaction kinetic experiments prove that the activation of water is the rate-determining step (RDS). The water activation mechanism is revealed by quasi in-situ X-ray photoelectron spectroscopy (XPS) and in-situ X-ray absorption fine structure (XAFS) measurements. The activation of water leads to the production of –H and –OH groups, which are further adsorbed on the oxygen atoms in P–O bond and Pd atoms, respectively. In addition, density functional theory (DFT) calculations indicate that the introduced oxygen facilitates the adsorption and activation of water molecules. This novel modulation strategy successfully sheds new light on the development of advanced catalysts for hydrolysis of AB and beyond.

Chiral nanoporous nanoarchitectures exhibit potential applications in various fields including chiral separation, sensing and catalysis. Two-dimensional (2D) supramolecular chemistry offers novel methods to build chiral nanoporous networks from achiral molecules. Herein, we report a series of chiral nanoporous networks built by an achiral precursor molecule via a stepwise annealing strategy on Ag(100). The nanoporous network morphologies and structural details are characterized by high-resolution scanning tunneling microscopy (STM). It is revealed that all vertices within networks are chiral. These chiral vertices are either dimeric, trimeric, or tetrameric. The connection of these chiral vertices gives rise to diverse chiral nanopores with varying shapes and sizes. A strict chirality correlation between nanopores and their vertices is determined. Specifically, enantiomeric vertices of one-pair nanopore enantiomers are always in identical type but opposite handedness. This work serves as a model to investigate the influence of vertex chirality on nanopore chirality of a supramolecular matrix. The attained chiral nanopores could potentially be utilized as templates for surface reaction, chiral recognition, etc. The mirror-symmetric silver adatoms clusters dictated by chiral nanopore are discerned.

Visible-light-initiated organic transformations have received much attention because of low cost, relative safety, and environmental friendliness. In this work, we report on a novel type of visible-light-driven photocatalysts, namely, porous nanocomposites of CdS-nanoparticle-decorated metal-organic frameworks (MOF), prepared by a simple solvothermal method in which porous MIL-100(Fe) served as the support and cadmium acetate (Cd(Ac)₂) as the CdS precursor. When the selective oxidation of benzyl alcohol to benzaldehyde is used as the probe reaction, the results show that the combination of MIL-100(Fe) and CdS semiconductor can remarkably enhance the photocatalytic efficiency at room temperature, as compared to that of pure CdS. The enhanced photocatalytic performance can be attributed to the combined effects of enhanced light absorption, more efficient separation of photogenerated electron-hole pairs, and increased surface area of CdS due to the presence of MIL-100(Fe). This work demonstrates that MOF-based composite materials hold great promise for applications in the field of solar-energy conversion into chemical energy.