The selective recognition of nanoparticles (NPs) can be achieved by nanoparticle-imprinted matrices (NAIMs), where NPs are imprinted in a matrix followed by their removal to form voids that can reuptake the original NPs. The recognition depends on supramolecular interactions between the matrix and the shell of the NPs, as well as on the geometrical suitability of the imprinted voids to accommodate the NPs. Here, gold NPs stabilized with citrate (AuNPs-cit) were preadsorbed onto a conductive surface followed by electrografting of p-aryldiazonium salts (ADS) with different functional groups. The thickness of the matrix was carefully controlled by altering the scan number. The AuNPs-cit were removed by electrochemical dissolution. The recognition of the NAIMs was determined by the reuptake of the original AuNPs-cit by the imprinted voids. We found that the recognition efficiency is a function of the thickness of the NAIM layer and is sensitive to the chemical structure of the matrix. Specifically, a subtle change of the functional group of the p-aryldiazonium building block, which was varied from an ether to an ester, significantly affected the recognition of the NPs.

Renewable energy technology and effective energy management are the most crucial factors to consider in the progress toward worldwide energy sustainability. Smart window technology has a huge potential in energy management as it assists in reducing energy consumption of indoor lighting and air-conditioning in buildings. Electrochromic (EC) materials, which can electrically modulate the transmittance of solar radiation, are one of the most studied smart window materials. In this work, highly transparent SnO2 inverse opal (IO) is used as the framework to electrochemically deposit amorphous WO3 layer to fabricate hybrid SnO2-WO3 core-shell IO structure. The hybrid structure is capable of effective near infrared (NIR) modulation while maintaining high visible light transparency in the colored and bleached states. By varying the initial diameter of the polystyrene (PS) opal template and the WO3 electrodeposition time, optimal results can be obtained with the smallest PS diameter of 392 nm and 180 s WO3 electrodeposition. In its colored state, the 392-SnO2-WO3-180 core-shell IO structure shows approximate to 70% visible light transparency, 62% NIR blockage at 1200 nm, and approximate to 15% drop in NIR blocking stability after 300 cycles. The SnO2-WO3 core-shell IO structure in this study is a promising EC material for advanced smart window technology.

Binder-free electrodes with core-shell structures have shown great potential in a variety of important energy storage systems. In order to endow the core-shell hierarchical structure with enhanced electrochemical properties, rationally designed and fabricated hierarchical structures with controllable morphology and great electrical conductivity are highly desired. In this work, a uniform dendritic SCo3O4@NiCo2S4 hierarchical structure grown on Ni foam was successfully designed and synthesized via sulfur-doping of Co3O4 (S-Co3O4) as the inner core with enhanced conductivity. The hierarchical electrode exhibited high areal capacity (10.9 mA h cm(-2) at a current density of 8 mA cm(-2)), a good rate performance (72.5% retention after increasing the current densities from 8 to 30 mA cm(-2)), and excellent cycling stability (97.3% retention after 5000 cycles). Moreover, a hybrid energy storage batterysupercapacitor device, constructed from a S-Co3O4@NiCo2S4 positive electrode and an active carbon (AC) negative electrode, showed high energy density and power density. Contributing to short ion diffusion, large electroactive sites and low contact resistance, our work not only demonstrates a promising electrode for energy storage battery-supercapacitor hybrid (BSH) devices, but also provides an attractive strategy for the design of electrode materials.

Long-term cycling stability is an important criterion and big challenge for pseudocapacitive materials. Ultra-stable manganese doped Co3O4 mesoporous nanoneedles were synthesized via one-step hydrothermal reaction followed by annealing grown on nickel foam (noted as MnxCoyO/NF, x + y = 2.25) for supercapacitors. The Mn doping in Co3O4 was confirmed by several techniques. Among various MnxCoyO/NF electrodes, the Mn1.5Co0.75O/NF demonstrated the superior electrochemical performance, with an excellent cycling stability of 104% capacitance retention after 10 000 charge-discharge cycles at 6 A g(-1), as well as a good capability (668.4 F g(-1) at 1 A g(-1 )compared to that of undoped Co3O4 which is 201.3 F g(-1)). Moreover, the assembled asymmetric supercapacitor based on Mn1.5Co0.75O/NF//graphene performs a high energy density of 25.88 Wh kg(-1) (at 359.5 W kg(-1)) and a high power density of 14.7 kW kg(-1) (at 10.63 Wh kg(-1)). The improved electrochemical properties are mainly owing to the enhanced intrinsic conductivity and electrochemical activity of Co3O4 after doped with appropriate Mn concentration. The three-dimensional nanostructure of mesoporous nanoneedle array grown on NF also provides short ion diffusion path and large active surface areas, contributing to the high rate performance and high energy density. This study may offer a new approach to fabricate the unique 3D nanostructured electrode materials based on doped metal oxides for supercapacitors with long-term cycling stability and high energy density.

Some articles have revealed that the electrodeposition of calcium phosphate (CaP) coatings entails a precursor phase, similarly to biomineralization in vivo. The chemical composition of the initial layer and its thickness are, however, still arguable, to the best of our knowledge. Moreover, while CaP and electrodeposition of metal coatings have been studied utilizing atom-probe tomography (APT), the electrodeposition of CaP ceramics has not been heretofore studied. Herein, we present an investigation of the CaP deposition on a gold substrate. Using APT and transmission electron microscopy (TEM) it is found that a mixture of phases, which could serve as transient precursor phases to hydroxyapatite (HAp), can be detected. The thickness of these phases is tens of nanometers, and they consist of amorphous CaP (ACP), dibasic calcium phosphate dihydrate (DCPD), and octacalcium phosphate (OCP). This demonstrates the value of using atomic-resolved characterization techniques for identifying the precursor phases. It also indicates that the kinetics of their transformation into the more stable HAp is not too fast to enable their observation. The coating gradually displays higher Ca/P atomic ratios, a porous nature, and concomitantly a change in its density.

The activity of chiral self-assembled monolayers (SAMs) in electrochemistry is reviewed. Chiral SAMs have been used as a means of introducing stereoselectivity in electron transfer at the electrode/electrolyte interface. In most cases, a cysteine-based SAM was used on gold electrodes. Different attempts have involved the application of chiral thiolated molecules, e.g., cyclodextrin, imprinting of chiral objects and competitive complexation. More recently, spintronics in which magnetic fields applied next to chiral SAM induced chiral effects, were also reported. Yet, there is much room for additional and innovative ideas in this field of electrochemistry.