A cobalt metalized polymer modulates the electronic structure of Pt nanoparticles to accelerate water dissociation kinetics

Herein, we construct a composite material of Pt-NPs@NPCNs-Co by anchoring Pt nanoparticles (Pt NPs) and Co-salen covalent organic polymer (Co-COP) onto N, P co-doped carbon nanotubes (NPCNs), thereby offering an integrated approach to enhance H₂O dissociation. The bimetallic catalyst Pt-NPs@NPCNs-Co demonstrates exceptional HER performance, and the overpotential at 40 mA cm^-2 is lower than that of 20% Pt/C. When the overpotential is 50 mV, the mass activity of Pt-NPs@NPCNs-Co is 2.8 times that of the commercial Pt/C catalyst. Experimental results reveal that the synergistic interplay between Pt NPs and Co contributes to the excellent electrocatalytic performance observed. Density function theory calculations found that Co effectively modulates the electronic structure of Pt NPs and lowers the activation energy of the Volmer step, thereby accelerating the water dissociation kinetics of Pt NPs. This research contributes to the advancement of knowledge regarding the development of more efficient bimetallic co-catalytic electrocatalysts in alkaline media.

Simple pyrolysis of graphene-wrapped PtNi nanoparticles supported on hierarchically N-doped porous carbon for sensitive detection of carbendazim

A novel electrochemical sensor was established based on graphene-wrapped PtNi nanoparticles supported on three-dimensional (3D) N-doped porous carbon (G-PtNi/3D-NPC) for the highly sensitive and selective detection of carbendazim (CBZ). In this sensing system, the encapsulation of PtNi nanoparticles (NPs) by graphene can effectively prevent the aggregation tendency and enhance the structural stability. The hierarchically porous nanostructures have a large specific surface area to expose a large number of active sites and the resulting enhanced electrical conductivity ultimate improves the electrocatalytic activity towards CBZ. Under the optimal conditions, the prepared sensor showed excellent electrochemical responses for the determination of CBZ with a linear range of 0.5-30 μM and lower limit of detection (LOD) of 0.04 μM (S/N = 3). It also shows excellent anti-interference ability at a working potential of 0.74 V. The feasibility of the senor is demonstrated for its practical assays in diluted peach and vegetable samples with acceptable recovery (95.8-97.3 %, peach; 97.2-97.6 %, vegetable) and a relative standard deviation (RSD) below 2.3%.

Tunable Aryl Alkyl Ionic Liquid Supported Synthesis of Platinum Nanoparticles and Their Catalytic Activity in the Hydrogen Evolution Reaction and in Hydrosilylation

Tunable aryl alkyl ionic liquids (TAAILs) are ionic liquids (ILs) with a 1-aryl-3-alkylimidazolium cation having differently substituted aryl groups. Herein, nine TAAILs with the bis(trifluoromethylsulfonyl)imide anion are utilized in combination with and without ethylene glycol (EG) as reaction media for the rapid microwave synthesis of platinum nanoparticles (Pt-NPs). TAAILs allow the synthesis of small NPs and are efficient solvents for microwave absorption. Transmission electron microscopy (TEM) shows that small primary NPs with sizes of 2 nm to 5 nm are obtained in TAAILs and EG/TAAIL mixtures. The Pt-NPs feature excellent activity as electrocatalysts in the hydrogen evolution reaction (HER) under acidic conditions, with an overpotential at a current density of 10 mA cm^-2 as low as 32 mV vs the reversible hydrogen electrode (RHE), which is significantly lower than the standard Pt/C 20% with 42 mV. Pt-NPs obtained in TAAILs also achieved quantitative conversion in the hydrosilylation reaction of phenylacetylene with triethylsilane after just 5 min at 200 °C.

Experimental and Theoretical Insights into Enhanced Hydrogen Evolution over PtCo Nanoalloys Anchored on a Nitrogen-Doped Carbon Matrix

The identification of synergistic effect of Pt-based alloys on hydrogen evolution reaction (HER) requires a combination of experimental studies and theoretical calculations. Here, we present the construction of uniform PtCo nanoparticles grown on N-doped carbon frameworks via pyrolyzing Pt and Co ions adsorbed polyaniline, whereby the nanostructure of the nanoalloys can be effectively tuned by controlling the calcination temperature. As-prepared PtCo@NC-900 shows the optimal HER performance in 0.5 M H2SO4, resulting in a high mass activity of 4.31 A mgPt-1 and excellent operation durability, which far exceeds that of commercial 20 wt % Pt/C (0.30 A mgPt-1). Density functional theory calculations further reveal that the improved HER activity on PtCo(111) is originated from the strong electronic interaction between Pt and Co with favorable electron transfer, allowing for a more suitable binding strength for hydrogen (i.e., ΔG*H = -0.164 eV) compared with that of pristine Pt(111) (-0.287 eV).

The Facile Deposition of Pt Nanoparticles on Reduced Graphite Oxide in Tunable Aryl Alkyl Ionic Liquids for ORR Catalysts

In this study, we present the facile formation of platinum nanoparticles (Pt-NPs) on reduced graphite oxide (rGO) (Pt-NP@rGO) by microwave-induced heating of the organometallic precursor ((MeCp)PtMe₃ in different tunable aryl alkyl ionic liquids (TAAIL). In the absence of rGO, transmission electron microscopy (TEM) reveals the formation of dense aggregates of Pt-NPs, with primary particle sizes of 2 to 6 nm. In contrast, in the Pt-NP@rGO samples, Pt-NPs are homogeneously distributed on the rGO, without any aggregation. Pt-NP@rGO samples are used as electrode materials for oxygen reduction reaction (ORR), which was assessed by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The electrochemical surface area (ECSA) and mass-specific activity (MA) increase up to twofold, compared with standard Pt/C 60%, making Pt-NP@rGO a competitive material for ORR.

Interface Nanoengineering of PdNi-S/C Nanowires by Sulfite-Induced for Enhancing Electrocatalytic Hydrogen Evolution

The interfacial structural design of materials in nanoscale is a promising approach to regulate the physicochemical properties of materials and further optimize material properties for a variety of potential applications. Herein, PdNi-S/C nanowires with inductive sulfite has been successfully crafted through hydrothermal synthesis and applied as a superior hydrogen evolution reaction (HER) catalyst. Based on the autocatalytic mechanism, PdNi alloy nanoparticles were synthesized by controlling reduction kinetics with the presence of formic acid. Meanwhile, the sulfite is selected as an effective inductive agent to form PdNi-S/C nanowires with amorphous interfaces. The morphology, composition, and electronic structure of the synthesized PdNi-S/C were studied in detail. The PdNi-S/C manifests excellent HER performance in alkaline solution with an overpotentials of 67 mV at current density of 10 mA cm^-2, a Tafel slope of 69.4 mV dec^-1, and significantly long-term durability. The improvement of HER performance of the PdNi-S/C is attributed to the one-dimensional nanowire structure, abundant sulfur vacancies and defects, and the synergistic effect between PdNi-S nanowires with the graphite carbon. Furthermore, this present work offers a novel method for structure adjustment of materials to effectively control their property and catalytic performance.

A one-pot route for the synthesis of Au@Pd/PMo12/rGO as a dual functional electrocatalyst for ethanol electro-oxidation and hydrogen evolution reaction

An in situ one-pot synthetic route for the synthesis of a Au@Pd/PMo₁₂/reduced graphene oxide (rGO) nanocomposite is presented, where the Keggin-type polyoxometalate phosphomolybdic acid (PMo₁₂) is used as both reducing and stabilizing agent. High-angle annular dark-field scanning transmission electron microscopy (HAADT-STEM), transmission electron microscopy (TEM), and X-ray diffraction analysis were applied to fully characterize the core–shell structure of Au@Pd/PMo₁₂ on the rGO matrix. Electrochemical studies showed how this nanocomposite acts as a dual electrocatalyst for the ethanol electro-oxidation reaction (EOR) and the hydrogen evolution reaction (HER). For the EOR, the Au@Pd/PMo₁₂/rGO electrocatalyst offers a low onset potential of −0.77 V vs. Ag/AgCl and a high peak current density of 41 mA cm⁻² in alkaline medium. This feature is discussed via detailed cyclic voltammetry (CV) studies illustrating how the superior performance of the synthetic nanocomposite could be attributed to the synergistic effect of Au, Pd, PMo₁₂ and rGO. Moreover, it has been confirmed that the proposed electrocatalyst exhibits low overpotentials for 10 mA cm⁻² current density (η₁₀) in different pH media. The values of η₁₀ were −109, 300 and 250 mV vs. RHE in acidic, basic and neutral media, respectively. Also, the ability of the electrocatalyst to provide high HER current density and its remarkable stability have been confirmed.

Au@Pd/PMo₁₂/rGO nanocomposite was synthesized and used as a dual-functional electrocatalyst for HER and EOR.