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We report a simple one-step chemical reduction strategy in deep eutectic solvents (DESs) for the fabrication of a PtV alloy nanonetwork (ANN)/multiwalled carbon nanotube (MWCNT) nanohybrid, which exhibits excellent electrocatalytic performance in both activity and stability for the methanol oxidation reaction (MOR). The as-synthesized nanohybrid was characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, confirming the formation of a porous nanonetwork structure composed of smaller PtV alloy nanoparticles (~3.8 nm) and the presence of strong electronic transfer interactions between Pt and alloyed V. The electrochemical properties of catalysts for the MOR were evaluated by using cyclic voltammetry and chronoamperometry techniques. The electrocatalytic activity, durability and CO tolerance ability of PtV ANNs/MWCNTs toward the MOR are found to be considerably higher than those of the Pt/MWCNT and commercial Pt/C catalysts. This investigation of the effect of several reaction parameters (e.g., scan rate and methanol concentration) indicates that the electrocatalytic oxidation of methanol on PtV ANNs/MWCNTs is a diffusion-controlled electrochemical process. The performance enhancement mechanism of MOR on the PtV ANN/MWCNT catalyst is analyzed based on the structure and electrochemical studies.

Through a two-way control of hexadecyl trimethyl ammonium bromide (CTAB) and hydrochloric acid (HCl), the PdCu nanoalloys with branched structures are synthesized in one step by hydrothermal reduction and used as electrocatalysts for formic acid oxidation reaction (FAOR). In this two-way control strategy, the CTAB is used as a structure-oriented surfactant, while a certain amount of HCl is used to control the reaction kinetics for achieving gradual growth of multi-dendritic structures. The characterizations including scanning transmission electron microscope (STEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) suggest that PdCu nanoalloys with unique multi-dendritic branches have favorable electronic structure and lattice strain for electrocatalyzing the oxidation of formic acid. In specific, among the electrocatalysts with different Pd/Cu ratios, the Pd1Cu1 branched nanoalloys have the largest electrochemically active surface area (ECSA) and the best performance for the FAOR. The catalytic activity of the Pd1Cu1 branched nanoalloys is 2.4 times that of commercial Pd black. After the chronoamperometry test, the Pd1Cu1 branched nanoalloys still maintain their original morphologies and higher current density than that of the commercial Pd black. In addition, in the CO-stripping tests, the initial oxidation potential and the oxidation peak potential of the PdCu branched nanoalloys for CO adsorption are lower than those of commercial Pd balck, evincing their better anti-poisoning performance.

As a novel non-aqueous green solvent that can deem to be the optimal substitution of conventional solvents and ionic liquids, deep-eutectic solvents (DESs) have attracted significant attention from academia and industry in terms of chemical synthesis in recent years. Herein, we report the highly effective preparation of Pt nanoparticles with hollow-opened structures (Pt HOSs) as an efficient electrocatalyst for methanol oxidation reaction (MOR) via a facile template-free solvothermal synthesis in DESs. The as-obtained Pt HOSs are consisted of well assembled secondary and tertiary branches, which can remarkably improve the utilization efficiency and electrocatalytic activity of Pt via promoting the access of electroactive species to the full-extent Pt surface. In this regard, the as-prepared Pt HOSs possess higher electrochemically active surface areas (ECSAs) and show improved electrochemical properties for MOR. Furthermore, the Pt HOSs retain a higher reactivity after the long-term testing compared with commercial Pt black, suggesting that they have enhanced electrocatalytic durability. In specific, the rational design of Pt HOSs in DESs may enrich the synthetic strategies for producing more electrocatalysts with impressive activity and stability.

Deep eutectic solvents are promising in the green synthesis of advanced functional materials owing to their several distinct advantages including good solubility, wide electrochemical window, high conductivity, low cost, nontoxicity and tolerance to humidity. Herein, we report a novel green protocol to design the hybrid PtCu nanoclusters on multi-walled carbon nanotubes in deep eutectic solvents medium without adding any surface controlling agent. Subsequently, the structure, elemental composition and electrocatalytic aspects of the as-synthesized nanohybrids are characterized by transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopic features and electrochemical investigations. Typically, the synthesis medium plays a key role to control the dispersion of Pt-based nanoparticles and to enhance the electronic transfer interaction among the catalytic nanoparticles and support material. On other hand, the addition of alloyed Cu not only further decreases the crystallite size of catalytic particles but also results in the formation of cluster nanostructure with the coarse surface. Moreover, the methanol oxidation electrocatalytic activity of the as-fabricated material is clearly composition dependent, their maximum mass activity (Pt/Cu mass ratio 1:0.25) is about 2.5 times that of the carbon nanotubes-supported monometallic Pt catalyst. And it also presents the good CO-tolerance ability and evident long-term electrochemical durability. This study suggests that the synthesis strategy in deep eutectic solvents is of great importance to design and fabricate the high-performance electrocatalysts for fuel cells applications.