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Acidic dissolution of transition metals from Pt based alloy catalysts for oxygen reduction reaction (ORR) is an unavoidable process during fuel cell operation. In this work we studied the effect of acid treatment of graphene-supported Pt 1 Ni x (x ) 0, 0.25, 0.5, 1, and 2) alloys on the kinetics of the ORR in both alkaline and acidic solutions together with the generation of OH radicals in alkaline solutions. The alloy nanoparticles were synthesized through coimpregnation and chemical reduction. The electronic and structural features of the alloy were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. The ORR performances were studied using cyclic voltammetry and rotating ring disk electrode techniques in 0.05 M H 2 SO 4 and 0.1 M NaOH, respectively. The alloy catalysts were more active than pure Pt toward ORR, and after acid treatment the ORR activity of Pt-Ni alloy was enhanced in both acidic and alkaline media. The maximum activity of the Pt-based catalysts was found with ca. 50 atom % Ni content in the alloys (Pt 1 Ni 1 @graphene). OH radicals were generated through dissociation of hydroperoxide at the catalysts' surface and detected by fluorescence technique using terephthalic acid as capture reagent, which readily reacts with OH radical to produce highly fluorescent product, 2-hydroxyterephthalic acid. More OH radicals were found to be generated at Pt 1 Ni 1 @graphene catalyst. This work may be valuable in the design of electrocatalysts with higher ORR activity but lower efficiency of OH radical generation.

Dual-band electrochromism is a phenomenon where materials can independently regulate the transmittance of visible (VIS) and near-infrared (NIR) light. Owing to their bistability, low energy consumption, and independent control over VIS and NIR regions, dual-band electrochromic (EC) devices have been of great significance to fully harnessing VIS and NIR light and building an energy-saving society. The past several years have witnessed the efforts put in developing novel EC materials to improve their dual-band optical performance through altering their composition, structural, and physicochemical features, which determine the optical behavior of dual-band EC devices. In this review, the concept, significance, working principle, and key influence factors of dual-band electrochromism are briefly introduced. Next, the up-to-date progress of dual-band EC materials including inorganic, organic, and composites materials are summarized, with a focus on material design, device fabrication, and performance optimization. Finally, the challenges and perspectives of dual-band EC materials and devices are also presented.

The integration of two quite different techniques, conventional electrochemistry and spectroscopy, into spectroelectrochemistry (SEC) provides a complete description of chemically driven electron transfer processes and redox events for different kinds of molecules and nanoparticles. SEC possesses interdisciplinary advantages and can further expand the scopes in the fields of analysis and other applications, emphasizing the hot issues of analytical chemistry, materials science, biophysics, chemical biology, and so on. Considering the past and future development of SEC, a review on the recent progress of SEC is presented and selected examples involving surface-enhanced Raman scattering (SERS), ultraviolet-visible (UV-Vis), near-infrared (NIR), Fourier transform infrared (FTIR), fluorescence, as well as other SEC are summarized to fully demonstrate these techniques. In addition, the optically transparent electrodes and SEC cell design, and the typical applications of SEC in mechanism study, electrochromic device fabrication, sensing and protein study are fully introduced. Finally, the key issues, future perspectives and trends in the development of SEC are also discussed.

Aqueous N-rich carbon dots (CDs), prepared by the microwave-assisted pyrolysis method, are applied as a dual sensing platform for both the fluorescent and electrochemical detection of 2,4,6-trinitrotoluene (TNT). The fluorescent sensing platform is established on the strong TNT-amino interaction which can quench the photoluminescence of amino functionalized CDs through charge transfer. The resultant linear detection ranges from 10 nM to 1.5 μM with a fast response time of 30 s. Glassy carbon electrode modified with CDs exhibits a fine capability for TNT reduction with the linear range from 5 nM to 30 μM, better than that obtained by the fluorescent method. Moreover, the minimum distinguishable response concentration with respect to these two methods is down to the nanomolar level with a high specificity and sensitivity.

We propose an ingenious method for large-scale fabrication of water-soluble photoluminescent carbon dots (CDs) by a one-step microwave route in the presence of citric acid and ethylenediamine.

The development of state‐of‐the‐art catalysts plays a crucial role in the fields of materials science and engineering for efficient energy conversion and storage. Although some excellent catalysts have been developed, considerable challenges remain to bring down the cost and increase the activity of catalysts. The emergence of carbon materials (i.e., activated carbon, graphite, fullerenes, carbon nanotubes, diamond, graphene, etc.) provides an excellent alternative to traditional catalysts. Considerable effort has been made to develop diverse carbon‐based catalysts, including carbon in itself, heteroatom‐doped carbon, carbon supported catalysts, carbon hybrids, and so on. Additionally, tremendous progress has been achieved in various catalysis fields, such as chemical synthesis, gas or oil desulfurization, biosensor, energy storage and conversion, organism photodegradation, etc. This article reviews the versatility of carbon family, and their endless catalytic properties and applications, from the viewpoint of materials and chemistry.

Novel Co-N-C hybrids were successfully fabricated via one-step pyrolysed soy milk with the aid of cobalt(II) nitrate in a synthetic process. Because of the formation of the Co-N-C structures, the resulting product showed excellent electrocatalytic activity for the ORR in alkaline electrolytes, potentially making Co-N-C a nonprecious metal cathode catalyst for ORR. The technique can also be scaled up easily and this research provides a great opportunity for industry to produce an eco-friendly carbon nanomaterial for fuel cells and other electrochemical energy devices.