Kinetically Manipulating the Nucleus Attachment to Create Atypical Defective Rh-Pt Alloyed Nanostructures as Active Electrocatalysts

Structural engineering of Pt-on-Rh hollow nanorods with high-performance peroxidase-like specific activity for colorimetric detection

The preparation of nanozymes with high specific activity is highly important for various applications. However, only a few nanozymes have specific activities comparable to natural enzymes. Herein, novel Pt-on-Rh hollow nanorods (PtRh HNRs) were developed, in which surface Pt exhibited adjustable dispersity and interior Rh served as the support. The optimized PtRh HNRs demonstrated high-performance peroxidase (POD)-like activity, with a specific activity as high as 1352 U mg-1, which was 3.86 times that of their monometallic Pt counterparts. Density functional theory (DFT) calculations illustrated that the presence of Rh decreased the energy barrier of the rate-determining step. When PtRh HNRs were used as nanozymes in the colorimetric detection of hydrogen peroxide (H2O2) and ascorbic acid (AA), the limits of detection (LODs) were as low as 9.97 μM and 0.039 μM, respectively. The current work highlights a facile and powerful strategy for manufacturing nanozymes with high specific activity and demonstrates that the prepared PtRh HNRs have the potential for analysis and determination.

Two-dimensional template-directed synthesis of one-dimensional kink-rich Pd3Pb nanowires for efficient oxygen reduction

Developing facile synthetic strategies toward ultrafine one-dimensional (1D) nanowires (NWs) with rich catalytic hot spots is pivotal for exploring effective heterogeneous catalysts. Herein, we demonstrate a two-dimensional (2D) template-directed strategy for synthesizing 1D kink-rich Pd₃Pb NWs with abundant grain boundaries to serve as high-efficiency electrocatalysts toward oxygen reduction reaction (ORR). In this one-pot synthesis, ultrathin Pd nanosheets were initially generated, which then served as self-sacrificial 2D nano-templates. A dynamic equilibrium growth was subsequently established on the 2D Pd nanosheets through the center-selected etching of Pd atoms and edge-preferred co-deposition of Pd/Pb atoms. This was followed by the oriented attachment of the generated Pd/Pb alloy nanograins and fragments. Thus, kink-rich Pd₃Pb NWs with rich grain boundary defects were obtained in high yield, and these NWs were used as electrocatalytic active catalysts. The surface electronic interaction between Pd and Pb atoms effectively decreased the surface d-band center to weaken the binding of oxygen-containing intermediates toward improved ORR kinetics. Specifically, the kink-rich Pd₃Pb NWs/C catalyst delivered outstanding ORR mass activity and specific activity (2.26 A⋅mg_Pd^-1 and 2.59 mA⋅cm^-2, respectively) in an alkaline solution. These values were respectively 13.3 and 10.8 times those of state-of-the-art commercial Pt/C catalyst. This study provides an innovative strategy for fabricating defect-rich low-dimensional nanocatalysts for efficient energy conversion catalysis.