Polymer and Carbon Spheres with an Embedded Shell of Plasmonic Gold Nanoparticles

Multilevel Hollow Phenolic Resin Nanoreactors with Precise Metal Nanoparticles Spatial Location toward Promising Heterogeneous Hydrogenations

Hollow nanostructures with fascinating properties have inspired numerous interests in broad research fields. Cell-mimicking complex hollow architectures with precise active components distributions are particularly important, while their synthesis remains highly challenging. Herein, a "top-down" chemical surgery strategy is introduced to engrave the 3-aminophenol formaldehyde resin (APF) spheres at nanoscale. Undergoing the cleavage of (Ar)CN bonds with ethanol as chemical scissors and subsequent repolymerization process, the Solid APF transform to multilevel hollow architecture with precise nanospatial distribution of organic functional groups (e.g., hydroxymethyl and amine). The transformation is tracked by electron microscopy and solid-state nuclear magnetic resonance techniques, the category and dosage of alcohol are pivotal for constructing multilevel hollow structures. Moreover, it is demonstrated the evolution of nanostructures accompanied with unique organic microenvironments is able to accurately confine multiple gold (Au) nanoparticles, leading to the formation of pomegranate-like particles. Through selectively depositing palladium (Pd) nanoparticles onto the outer shell, bimetallic Au@APF@Pd catalysts are formed, which exhibit excellent hydrogenation performance with turnover frequency (TOF) value up to 11257 h^-1 . This work provides an effective method for precisely manipulating the nanostructure and composition of polymers at nanoscale and sheds light on the design of catalysts with precise spatial active components.

Embedded Au Nanoparticles-Based Ratiometric Electrochemical Sensing Strategy for Sensitive and Reliable Detection of Copper Ions

The ratiometric method allows the measurement of ratio changes between two signals, which can reduce the detection signal fluctuations caused by distinct background conditions and greatly improve the reproducibility and reliability of detection. However, in contrast with the emerging dual excitation or dual emission dyes applied in ratiometric luminescence measurement, only a few internal reference probes have been exploited for ratiometric electrochemical detection. In this paper, a gold nanoparticles@carbonized resin nanospheres composite with thermally reduced graphene oxide as scaffold (AuNPs@CRS-TrGNO) has been fabricated, and the AuNPs embedded in the CRS were first used as an internal reference probe for ratiometric electrochemical detection. The detachment and aggregation of AuNPs is suppressed by embedding in the CRS, so its redox signal is very stable, which provides feasibility for ratiometric detection. Moreover, the embedment of AuNPs, carbonization of resin spheres, and hybridization with TrGNO all have played positive roles in improving the charge transfer rate, which leads to excellent electrochemical performance of the composite. Based on these characteristics of the AuNPs@CRS-TrGNO, a new ratiometric electrochemical detection platform was constructed, and copper ions (Cu²⁺) in simulated seawater were successfully detected. This ratiometric method has the advantages of simple design and convenient operation, and obviously it improves the reproducibility and reliability of the electrochemical sensor.

Low-cost palladium decorated on m-aminophenol-formaldehyde-derived porous carbon spheres for the enhanced catalytic reduction of organic dyes

A novel method for the synthesis of recyclable Pd@PCS catalyst was applied for the reduction of CV, EY, and SY.

Significant Enhancement of Water Splitting Activity of N-Carbon Electrocatalyst by Trace Level Co Doping

Replacement of precious metal electrocatalysts with highly active and cost efficient alternatives for complete water splitting at low voltage has attracted a growing attention in recent years. Here, this study reports a carbon-based composite co-doped with nitrogen and trace amount of metallic cobalt (1 at%) as a bifunctional electrocatalyst for water splitting at low overpotential and high current density. An excellent electrochemical activity of the newly developed electrocatalyst originates from its graphitic nanostructure and highly active Co-Nx sites. In the case of carefully optimized sample of this electrocatalyst, 10 mA cm(-2) current density can be achieved for two half reactions in alkaline solutions-hydrogen evolution reaction and oxygen evolution reaction-at low overpotentials of 220 and 350 mV, respectively, which are smaller than those previously reported for nonprecious metal and metal-free counterparts. Based on the spectroscopic and electrochemical investigations, the newly identified Co-Nx sites in the carbon framework are responsible for high electrocatalytic activity of the Co,N-doped carbon. This study indicates that a trace level of the introduced Co into N-doped carbon can significantly enhance its electrocatalytic activity toward water splitting.

Photonic metal–polymer resin nanocomposites with chiral nematic order

Metal nanoparticles that spontaneously nucleate in the chiral channels of a polymer resin templated by cellulose nanocrystals form ink-jet printed images.