Phosphorus-Alloying as a Powerful Method for Designing Highly Active and Durable Metal Nanoparticle Catalysts for the Deoxygenation of Sulfoxides: Ligand and Ensemble Effects of Phosphorus

Manipulating Oxygen Reduction Mechanisms of Platinum with Nonmetallic Phosphorus and Metallic Copper Synergistic Alloying

Alloying of platinum (Pt) nanostructures with heteroelements, commonly including transition-metals and nonmetals, is an effective strategy to improve the electrocatalytic performance for oxygen reduction reaction (ORR). However, the distinct mechanisms by which metal/nonmetal alloying improves ORR activity remain unclear. Herein, based on the successful alloying of porous network Pt nanospheres (NSs) with metallic copper (Cu) and non-metallic phosphorus (P) and systematically integrating the electrochemical tests, density functional theory calculations, and in situ electrochemical Raman spectroscopy, this study reveals that the internal Cu-alloying is responsible for modulating the binding strength of oxygenated intermediates to lower the free energy barrier of the potential-determining step (PDS) along the ORR associative mechanism, while the further surface P-alloying can transform the ORR pathway to dissociative mechanism, in which the PDS has a quite low barrier. As a result, the carbon-supported P/Cu co-alloyed porous network Pt nanospheres (P-PtCuNSs/C) catalyst synthesized by confinement growth and post-phosphorization demonstrates excellent electrocatalytic ORR activity and stability compared to the commercial Pt/C catalyst both in half-cells and proton exchange membrane fuel cells. In particular, the hydrogen (H2)-oxygen (O2) single cell with P-PtCuNSs/C as the cathode catalyst achieves a high mass activity of 0.52 A mgPt -1 at the voltage of 0.90 V, surpassing the U.S. Department of Energy's current activity target.

Heterogeneously catalyzed thioether metathesis by a supported Au-Pd alloy nanoparticle design based on Pd ensemble control

C-S bond metathesis of thioethers has gained attention as a new approach to the late-stage diversification of already existing useful thioethers with molecular frameworks intact. However, direct or indirect thioether metathesis is scarcely reported, and heterogeneously catalyzed systems have not been explored. Here, we develop heterogeneously catalyzed direct thioether metathesis using a supported Au-Pd alloy nanoparticle catalyst with a high Au/Pd ratio. The Au-diluted Pd ensembles suppress the strong π-adsorption of diaryl thioethers on the nanoparticles and promote transmetalation via thiolate spill-over onto neighboring Au species, enabling an efficient direct thioether metathesis.

Transition Metal Phosphide Nanoarchitectonics for Versatile Organic Catalysis

Transition metal phosphides (TMP) posses unique physiochemical, geometrical, and electronic properties, which can be exploited for different catalytic applications, such as photocatalysis, electrocatalysis, organic catalysis, etc. Among others, the use of TMP for organic catalysis is less explored and still facing many complex challenges, which necessitate the development of sustainable catalytic reaction protocols demonstrating high selectivity and yield of the desired molecules of high significance. In this regard, the controlled synthesis of TMP-based catalysts and thorough investigations of underlying reaction mechanisms can provide deeper insights toward practical achievement of desired applications. This review aims at providing a comprehensive analysis on the recent advancements in the synthetic strategies for the tailored and tunable engineering of structural, geometrical, and electronic properties of TMP. In addition, their unprecedented catalytic potential toward different organic transformation reactions is succinctly summarized and critically analyzed. Finally, a rational perspective on future opportunities and challenges in the emerging field of organic catalysis is provided. On the account of the recent achievements accomplished in organic synthesis using TMP, it is highly anticipated that the use of TMP combined with advanced innovative technologies and methodologies can pave the way toward large scale realization of organic catalysis.

A copper nitride nanocube catalyst for highly efficient hydroboration of alkynes

The hydroboration of alkynes with bis(pinacolato)diboron is a useful method for the synthesis of vinyl boronate esters, which are essential intermediates in organic syntheses. Copper catalysts have been used extensively in these reactions. However, previously reported Cu-catalyst systems inevitably require additives and elevated temperatures. Herein, we report, for the first time, a simple and efficient hydroboration of alkynes under additive-free and mild reaction conditions (i.e., at a temperature of 30 °C) using a copper nitride nanocube (Cu₃N NC) catalyst. A wide range of alkynes can be transformed into their corresponding boronate esters. Cu₃N NCs are also applicable in the hydroboration of alkynes with tetrahydroxydiboron to synthesize vinyl boronic acids. Moreover, the Cu₃N NCs were easily separated by simple filtration and could be reused several times without any loss of their original activity. Hence, these highly active and reusable Cu₃N NC catalysts offer an environmentally friendly route for the efficient production of vinyl boronates.