Insight into the effects of the crystal phase of Ru over ultrathin Ru@Pt core-shell nanosheets for methanol electrooxidation

Sub-10 nm PdNi@PtNi Core-Shell Nanoalloys for Efficient Ethanol Electro-Oxidation

By controlling the structure and composition of Pt-based nanoalloys, the ethanol oxidation reaction (EOR) performances of Pt alloy catalysts can be effectively improved. Herein, we successfully synthesis sub-10 nm PdNi@PtNi nanoparticles (PdNi@PtNi NPs) with a core-shell structure by a one-pot method. The sub 10 nm core-shell nanoparticles possess more effective atoms and exhibit a synergistic effect which can lead to a shift in the d-band center and alter binding energies toward adsorbates. Due to the synergistic effect and unique core-shell structure, the PdNi@PtNi NP catalysts exhibit excellent electrocatalytic performance for ethanol oxidation reactions in alkaline, achieving 9.30 times more mass activity and 7.05 times more specific activity that of the state-of-the-art Pt/C catalysts. Moreover, the stability of PdNi@PtNi NPs was also greatly improved over PtNi nanoparticles, PtPd nanoparticles, and commercial Pt/C. This strategy provides a new idea for improving the electrocatalytic performance of Pt-based catalysts for EORs.

Ni(II)-Incorporated Ethylene Glycol-Linked Tetraphenyl Porphyrin-Based Covalent Organic Polymer as a Catalyst for Methanol Electrooxidation

Methanol oxidation reaction (MOR) is a perfect alternative to the conventional oxygen evolution reaction (OER), generally utilized as the anode reaction for hydrogen generation via the electrochemical water splitting method. Moreover, MOR is also relevant to direct methanol fuel cells (DMFCs). These facts motivate the researchers to develop economical and efficient electrocatalysts for MOR. Herein, we have introduced an ethylene glycol-linked tetraphenyl porphyrin-based (EG-POR) covalent organic polymer (COP). The Ni(II)-incorporated EG-POR material Ni-EG-POR displayed excellent OER and MOR activities in an alkaline medium. The materials were thoroughly characterized using 13C solid-state NMR, Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) surface area analyzer, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), and powder X-ray diffraction (PXRD) techniques. These organic-inorganic hybrid materials showed high chemical and thermal stability. Ni-EG-POR requires an overpotential of 400 mV (vs RHE) in OER and 190 mV (vs RHE) in MOR to achieve a current density of 10 mA cm-2. In addition, the catalyst also showed excellent chronoamperometric and chronopotentiometric stability, indicating that the catalyst can provide stable current over a longer period and its potential as a non-noble metal MOR catalyst.

Sulfur and phosphorus co-doping optimized electronic structure and modulated intermediate affinity on PdSP metallene for ethanol-assisted energy-saving H2 production

Coupling cathodic hydrogen evolution reaction (HER) and anodic electrochemical oxidation of organic small molecules in a co-electrolysis system could simultaneously realize high-value chemical generation and energy-saving hydrogen production, which, however, require high-performance electrocatalysts. In this work, we developed a one-step solvothermal method to synthesize S, P-co-doped Pd metallene (PdSP metallene) and employed it as a bifunctional electrocatalyst for both the HER and ethanol oxidation reaction (EOR). The co-doping of S and P atoms into Pd metallene could introduce multiple active sites and increase the electrochemically-active surface area. Moreover, the electronic interactions between Pd, S, and P atoms could regulate the electronic structure of the active sites and modulate the intermediate affinity on the resultant PdSP metallene, thus boosting the electrocatalytic HER and EOR performance. In the HER-EOR co-electrolysis system with bifunctional PdSP metallene electrocatalysts, only a 0.88 V of electrolysis voltage was required to fulfill 10 mA cm^-2 current density, much lower than that of pure water electrolysis (1.41 V) using the same electrocatalysts.

Plate-Like Colloidal Metal Nanoparticles

The pseudo-two-dimensional (2D) morphology of plate-like metal nanoparticles makes them one of the most anisotropic, mechanistically understood, and tunable structures available. Although well-known for their superior plasmonic properties, recent progress in the 2D growth of various other materials has led to an increasingly diverse family of plate-like metal nanoparticles, giving rise to numerous appealing properties and applications. In this review, we summarize recent progress on the solution-phase growth of colloidal plate-like metal nanoparticles, including plasmonic and other metals, with an emphasis on mechanistic insights for different synthetic strategies, the crystallographic habits of different metals, and the use of nanoplates as scaffolds for the synthesis of other derivative structures. We additionally highlight representative self-assembly techniques and provide a brief overview on the attractive properties and unique versatility benefiting from the 2D morphology. Finally, we share our opinions on the existing challenges and future perspectives for plate-like metal nanomaterials.