A platinum nanoparticle doped self-assembled peptide bolaamphiphile hydrogel as an efficient electrocatalyst for the hydrogen evolution reaction

Noble metal-based nanomaterials have shown great potential for catalytic application with higher selectivity and activity. Owing to their self-assembly properties with various molecular interactions, peptides play an essential role in the controlled synthesis of noble metal-based catalysts with high surface area. In this work, a phenylalanine (F) and tyrosine (Y) based peptide bolaamphiphile is prepared by solution-phase peptide synthesis. The peptide bolaamphiphile readily self-assembles into a hydrogel with a cross-linked nanofibrillar network. The platinum nanoparticles (Pt NPs) are in situ generated within the cross-linked nanofibrillar network of the hydrogel matrix of the peptide bolaamphiphile. Benefiting from the synergistic properties of the Pt nanoparticles doped on three-dimensional fibrous networks, Pt6@hydrogel shows efficient catalytic activity for the electrochemical hydrogen evolution reaction (HER) in 0.5 M H2SO4 solution. The Pt6@hydrogel requires an overpotential of 45 mV at -10 mA cm-2 with a Tafel slope of 52 mV dec-1. The Pt6@hydrogel also shows electrocatalytic activity in basic and neutral pH solutions. The excellent activity and stability of Pt6@hydrogel for the HER shows great potential for energy conversion applications.

Crucial role of an aerophobic substrate in bubble-propelled nanomotor aggregation

A bubble-propelled autonomous micro/nanomotor (MNM) is a device driven by a catalytic reaction that involves a solid-liquid-gas interface, which in turn is a key factor in achieving effective propulsion. Generally, modifying the liquid phase by adding surfactants can improve propulsion, but it has several disadvantages. It is reported that the rapid separation of bubbles will accelerate the movement of MNMs. Our focus is on methods to drive the motor efficiently by controlling the wettability of the solid phase, accelerating bubble separation without compromising the activity of the catalyst. In this study, different from most of the previous studies on moving MNMs, a static Pt loaded TiO₂ nanowire aggregation was utilized as a nanomotor aggregation to investigate the wettability of the solid phase on bubble release. In comparison to an underwater aerophilic solid phase, in which bubbles are strongly held on the surface, the nanomotor's aggregation showed good aerophobicity. In particular, after UV illumination for 30 s, the nanomotor's aggregation became superaerophobic, which significantly promoted the release of O₂ bubbles. The results of this study reveal how to modify the detachment behaviour of bubbles by controlling the aerophobic behaviour of solid surfaces of autonomous MNMs in an aqueous medium.

Correlation of the ratio of metallic to oxide species with activity of PdPt catalysts for methane oxidation

Activity of catalysts increase linearly with increasing ratio of Pd/Pt bimetallic to oxide species as observed in XRD.

Rapid synthesis of ultrasmall platinum nanoparticles supported on macroporous cellulose fibers for catalysis

Herein, we report a facile method for the synthesis of platinum nanoparticles (PtNPs) about 2.25 nm in size by heating a solution of chloroplatinic acid and sodium rhodizonate. The PtNPs were synthesized in about 5 min. The PtNPs were supported on macroporous cellulose fibers that were obtained from Kimwipe paper (KWP). The cellulose fiber-supported PtNPs (PtNPs@KWP) exhibited excellent catalytic activity towards the reduction of organic pollutants [e.g. methyl orange (MO)] in the presence of hydrogen (H₂) gas and formic acid (FA). FA and H₂ gas were utilized as clean and alternative reducing agents. The reduction of MO was performed in two different types of water matrices viz. deionized water (DIW) and simulated fresh drinking water (FDW). In both water matrices, the FA mediated reduction of MO was found to be faster than the H₂ gas-bubbled one. The PtNPs@KWP demonstrated excellent cycling stability without leaching the PtNPs or platinum ions into the solution for at least five cycles.

A graphitic carbon nitride–titania nanocomposite as a promising catalyst support for electro-oxidation of methanol

A graphitic carbon nitride–titania nanocomposite has been synthesized as a catalyst support for Pt which enhanced the electrocatalytic methanol oxidation reaction.

A green synthesis of “naked” Pt and PtPd catalysts for highly efficient methanol electrooxidation

A green synthesis of “naked” Pt and PtPd catalysts with clean surfaces is proposed for highly efficient methanol electrooxidation.

Use of feedback system control in optimizing chemical combinations to synthesize nanoparticles with desired characteristics

Defining desired chemical combinations through the FSC method.