Search

Seeking efficient, stable, and inexpensive electrocatalysts applied to water splitting and fuel cells in acidic media is still challenging for the development of renewable energy. Herein, we propose a single atom catalyst based on heterojunction composed of Pd–C4N and XMoY (X, Y = S, Se, Te), and conduct a detailed exploration of its oxygen reduction reaction (ORR), oxygen reduction reaction (OER), and hydrogen evolution reaction (HER) catalytic performance using density functional theory methods. First, all Pd–C4N/XMoY is proven to have good stability by calculating binding energy. Then, the ORR/OER electrocatalytic behavior of Pd–C4N/XMoY is investigated, and the potential-determining step of most catalysts for ORR is *OH reduction, while for the OER, it is *OH to *O. Additionally, all catalysts exhibit good catalytic activity for the ORR/OER, but only five have better catalytic activity than Pt(111). In particular, Pd–C4N/SMoSe exhibits a negligible potential barrier for the HER (−0.004 V). Pd–C4N/SeMoTe presents immense trifunctional activities toward ORR/OER/HER with overpotentials of 0.32/0.28/–0.02 V. The electronic structure analysis proves that the high activity is attributed to the good conductivity of the material itself and the adjustable binding ability of the *OH. Our report contributes to comprehending and designing more efficient single-atom catalysts to meet the demand for multifunctional catalysts. [ABSTRACT FROM AUTHOR]

The electromagnetic pollution problem is becoming increasingly serious due to the speedy advance of electronic communication devices. There are broad application prospects for the development of flexible, wearable composite films with high electromagnetic interference (EMI)-shielding performance. The MX@AC composite films were prepared from MXene, silver nanowires (AgNWs) and cellulose nanocrystals (CNCs) with a sandwich structure. Benefiting from the upper and lower frame structure formed by winding 1D AgNWs and CNC, the tensile strength of the MX@AC was improved to 35 MPa (12.5 wt% CNC content) from 4 MPa (0 wt% CNC content). The high conductivity of MXene and AgNWs resulted in the MX@AC composite film conductivity up to 90,670 S/m, EMI SE for 90 dB, as well as SSE/t up to 7797 dB cm2 g−1. And the MX@AC composite film was tested for practical application, showing that it can effectively isolate electromagnetic waves in practical application. [ABSTRACT FROM AUTHOR]

NiPS3, one of the most promising catalysts among transition metal trichalcogenidophosphates (MTPs) in hydrogen evolution reaction (HER) electrocatalysis, is still inhibited by its unsatisfactory activity originating from its semiconducting nature and inert basal plane. Here, it is proposed, for the first time, to engineer the basal surface activity of NiPS3 by nonmetal heteroatom doping, and predict that the degree to which the valance band of NiPS3 is filled dominates not only the electrical conductivity of the catalyst, but also the strength of hydrogen adsorption at its surface. Direct experimental evidence is offered that in all the single nonmetal doping samples, C‐doped NiPS3 exhibits the optimum activity owing to its moderate filled state of valance band and that C, N codoping even shows Pt‐like activity with an ultralow overpotential of 53.2 mV to afford 10 mA cm−2 current density and a high exchange current density of 0.7 mA cm−2 in 1 m KOH. The findings that less valance electrons of dopants than substitutional atoms are of pivotal importance for improving HER activity of NiPS3 catalyst pave the way for readily designing novel MTPs of ever high performance to replace the incumbent Pt‐based catalysts. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) plays a critical part in natural and artificial water splitting reactions and also facilitates realization of the sunlight-to-fuel light-harvesting process. Because this procedure is regarded as a hindrance of electron transfer, finding robust and low-cost OER catalysts to fulfill the requirements of increasing the rate of the reaction is favored. In this work, we first developed the anodic cyclic voltammetry (CV) electrodeposition method and obtained amorphous iron nickel oxide thin films (FeNiOx); we then performed a systematic study of the electrochemical conditions and the optimization results. The crystallinity and morphology of the thin film with superior electrochemical performance were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). In addition, investigation of the electrochemical OER performance suggested that FeNiOx has the highest activity among these samples. A small onset overpotential of 300 mV was achieved, and the Tafel slope was as low as 38 mV dec−1. The significance of this study is the systematic investigation of the catalytic composition, the simple deposition conditions, the facile and fast anodic CV electrodeposition method, and the remarkable performance and stability of the catalyst in alkaline media. [ABSTRACT FROM AUTHOR]