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Co and Fe Codoped WO <sub/>2.72</sub> as Alkaline‐Solution‐Available Oxygen Evolution Reaction Catalyst to Construct Photovoltaic Water Splitting System with Solar‐To‐Hydrogen Efficiency of 16.9%
摘要： Oxygen evolution electrode is a crucial component of efficient photovoltaic-water electrolysis systems. Previous work focuses mainly on the effect of electronic structure modulation on the oxygen evolution reaction (OER) performance of 3d-transition-metal-based electrocatalyst. However, high-atomic-number W-based compound with complex electronic structure for versatile modulation is seldom explored because of its instability in OER-favorable alkaline solution. Here, codoping induced electronic structure modulation generates a beneficial effect of transforming the alkaline-labile WO2.72 (WO) in to efficient alkaline-solution-stable Co and Fe codoped WO2.72 (Co&Fe-WO) with porous urchin-like structure. The codoping lowers the chemical valence of W to ensure the durability of W-based catalyst, improves the electron-withdrawing capability of W and O to stabilize the Co and Fe in OER-favorable high valence state, and enriches the surface hydroxyls, which act as reactive sites. The Co&Fe-WO shows ultralow overpotential (226 mV, J = 10 mA cm?2), low Tafel slope (33.7 mV dec?1), and good conductivity. This catalyst is finally applied to a photovoltaic-water splitting system to stably produce hydrogen for 50 h at a high solar-to-hydrogen efficiency of 16.9%. This work highlights the impressive effect of electronic structure modulation on W-based catalyst, and may inspire the modification of potential but unstable catalyst for solar energy conversion.
关键词： electrocatalysis,photovoltaic water splitting,oxygen evolution reaction,codoping,WO2.72
更新于2025-11-14 17:04:02
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Surface-Immobilized Conjugated Polymers Incorporating Rhenium Bipyridine Motifs for Electrocatalytic and Photocatalytic CO <sub/>2</sub> Reduction
摘要： The solar-driven conversion of CO2 to value-added products provides a promising route for solar energy storage and atmospheric CO2 remediation. In this report, a variety of supporting electrode materials were successfully modified with a [2,2′-bipyridine]-5,5′-bis(diazonium) rhenium complex through a surface-localized electropolymerization method. Physical characterization of the resulting multilayer films confirms that the coordination environments of the rhenium bipyridine tricarbonyl sites are preserved upon immobilization and that the polymerized catalyst moieties exhibit long-range structural order with uniform film growth. UV?vis studies reveal additional absorption bands in the visible region for the polymeric films that are not present in the analogous rhenium bipyridine complexes. Electrochemical studies with modified graphite rod electrodes show that the electrocatalytic activity of these films increases with catalyst loading up to an optimal value, beyond which electron and mass transport through the material become rate-limiting. Electrocatalytic studies performed at ?2.25 V vs Fc/Fc+ for 2 h reveal CO production with faradaic efficiencies and turnover numbers up to 99% and 3606, respectively. Photocatalytic studies of the modified TiO2 devices demonstrate enhanced activity at low catalyst loadings, with turnover numbers up to 70 during 5 h of irradiation.
关键词： metallopolymers,surface modification,photocatalysis,rhenium bipyridine,solar energy conversion,electrocatalysis
更新于2025-09-23 15:23:52
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Ultrasound-Assisted Nitrogen and Boron Co-doping of Graphene Oxide for Efficient Oxygen Reduction Reaction
摘要： Development of naturally abundant, low cost, and energy-efficient electrocatalysts for the oxygen reduction reaction (ORR) is essential for commercialization of fuel cells. In this work, we report simple ultrasonication assisted synthesis of nitrogen and boron dual-doped graphene oxide (NB/GO) and demonstrate its application as an effective ORR catalyst realizing predominantly 4e? reduction of O2 to OH? in 0.1 M KOH. Enhanced ORR electrocatalysis of the dual B and N co-doped GO as opposed to GO singly doped with B or N arises from the synergistic interaction of the boron and nitrogen species. The content and configuration of both N and B dopants can be readily tailored by controlling the ultrasonic conditions, thereby permitting tuning of the ORR activity. Furthermore, the developed NB/GO metal-free catalyst exhibited very promising long-term durability and resistance to methanol poisoning compared to the state of the art Pt/C catalyst.
关键词： Oxygen reduction reaction,Graphene,Doping,Electrocatalysis
更新于2025-09-23 15:23:52
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A Selective Earth-Abundant System for CO <sub/>2</sub> Reduction: Comparing Photo- and Electrocatalytic Processes
摘要： The valorization of CO2 via photo- or electrocatalytic reduction constitutes a promising approach toward the sustainable production of fuels or value-added chemicals using intermittent renewable energy sources. For this purpose, molecular catalysts are generally studied independently with respect to the photo- or the electrochemical application, although a unifying approach would be much more effective with respect to the mechanistic understanding and the catalyst optimization. In this context, we present a combined photo- and electrocatalytic study of three Mn diimine catalysts, which demonstrates the synergistic interplay between the two methods. The photochemical part of our study involves the development of a catalytic system containing a heteroleptic Cu photosensitizer and the sacrificial BIH reagent. The system shows exclusive selectivity for CO generation and renders turnover numbers which are among the highest reported thus far within the group of fully earth-abundant photocatalytic systems. The electrochemical part of our investigations complements the mechanistic understanding of the photochemical process and demonstrates that in the present case the sacrificial reagent, the photosensitizer and the irradiation source can be replaced by the electrode and a weak Br?nstedt acid.
关键词： photocatalysis,electrocatalysis,manganese,copper,carbon dioxide utilization
更新于2025-09-23 15:23:52
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In situ electrochemical reduction assisted assembly of a graphene-gold nanoparticles@polyoxometalate nanocomposite film and its high response current for detection of hydrogen peroxide
摘要： The nanocomposite film including polyoxometalate (POM) cluster K28Li5H7P8W48O184·92H2O (P8W48), reduced graphene oxide (rGO) and Au nanoparticles (Au NPs) was successfully fabricated by electrochemical reduction assisted technique. This synthesis was novel, convenient, and environmentally friendly. Moreover, the time of fabricating process was greatly shorten to about 1 hour comparing to that of the traditional method of layer by layer (LbL) self-assembly. The reduced P8W48 was served as reducing agent, stabilizer and bridging molecules simultaneously in the composite film. The structure of the composite material was verified by comprehensive characterization using scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The investigation of the electrocatalysis for H2O2 showed that the {PEI/rGO}-Au@P8W48 modified electrode has high catalytic activity, good sensitivity, good selectivity, low detection limit and fast response. In addition, the result indicated that the electrocatalytic activity of the electrode with Au NPs was better than that of the electrode without Au NPs. The enhanced catalytic property was attributed to the synergistic effect of the rGO, P8W48 and Au NPs.
关键词： graphene,hydrogen peroxide,Au nanoparticles,electrocatalysis,polyoxometalates
更新于2025-09-23 15:22:29
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Electrochemistry of Atomically Precise Metal Nanoclusters
摘要： Thiolate-protected metal nanoparticles containing a few to few hundred metal atoms are interesting materials exhibiting unique physicochemical properties. They encompass the bulk-to-molecule transition region, where discrete electronic states emerge and electronic band energetics yield to quantum con?nement e?ects. Recent progresses in the synthesis and characterization of ultrasmall gold nanoparticles have opened up new avenues for the isolation of extremely monodispersed nanoparticles with atomically precision. These nanoparticles are also called nanoclusters to distinguish them from other regular metal nanoparticles with core diameter >2 nm. These nanoclusters are typically identi?ed by their actual molecular formulas; prominent among these are Au25(SR)18, Au38(SR)24, and Au102(SR)44, where SR is organothiolate. A number of single crystal structures of these nanoclusters have been disclosed. Researchers have e?ectively utilized density functional theory (DFT) calculations to predict their atomic and electronic structures, as well as their physicochemical properties. The atomically precise metal nanoclusters have been the focus of recent studies owing to their novel size-speci?c electrochemical, optical, and catalytic properties. In this Account, we highlight recent advances in electrochemistry of atomically precise metal nanoclusters and their applications in electrocatalysis and electrochemical sensing. Compared with gold nanoclusters, much less progress has been made in the electrochemical studies of other metal nanoclusters, and thus, we mainly focus on the electrochemistry and electrochemical applications of gold-based nanoclusters. Voltammetry has been extremely powerful in investigating the electronic structure of metal nanoclusters, especially near HOMO and LUMO levels. A sizable opening of HOMO?LUMO gap observed for Au25(SR)18 gradually decreases with increasing nanocluster size, which is in line with the change in the optical gap. Heteroatom-doping has been a powerful strategy to modify the optical and electrochemical properties of metal nanoclusters at the atomic level. While the superatom theory predicts 8-electron con?guration for [Au25(SR)18]? and many doped nanoclusters thereof, Pt- and Pd-doped [PtAu24(SR)18]0 and [PdAu24(SR)18]0 nanoclusters show dramatically di?erent electronic structures, as manifested in their optical spectra and voltammograms, suggesting the occurrence of the Jahn?Teller distortion in these doped nanoclusters. Furthermore, metal-doping may alter their surface binding properties, as well as redox potentials. Metal nanoclusters o?er great potential for attaining high activity and selectivity in their electrocatalytic applications. The well-de?ned core?shell structure of a metal nanocluster is of special advantage because the core and shell can be independently engineered to exhibit suitable binding properties and redox potentials. We discuss recent progress made in electrocatalysis based upon metal nanoclusters tailored for water splitting, CO2 conversion, and electrochemical sensing. A well-de?ned model nanocatalyst is absolutely necessary to reveal the detailed mechanism of electrocatalysis and thereby to lead to the development of a new e?cient electrocatalyst. We envision that atomically controlled metal nanoclusters will enable us to systematically optimize the electrochemical and surface properties suitable for electrocatalysis, thus providing a powerful platform for the discovery of ?nely tuned nanocatalysts.
关键词： quantum con?nement,electrocatalysis,atomically precise metal nanoclusters,electrochemistry,electrochemical sensing
更新于2025-09-23 15:21:21
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Transparent Conductive Materials (Materials, Synthesis, Characterization, Applications) || Metal Nanowires
摘要： Metal nanowires are one-dimensional entities of metals of either single crystalline or polycrystalline nature [1]. Metal nanowires have attracted tremendous research attention since the last two decades, because of their important applications in plasmonics [2], electronics [3], electrocatalysis [4], and so on. In the past decade, researchers have attempted to coat metal nanowires on a transparent substrate as a transparent conductive ?lm (TCF) [5–7]. The visible light transparency and the conductivity of TCFs on the basis of metal nanowires have improved rapidly, being comparable with the performance of the state-of-the-art indium tin oxide (ITO) TCFs [8–10]. The recognition of the potential applications of metal nanowire TCFs stimulates research zeal for the synthesis of metal nanowires. So far, a range of metal nanowires have been synthesized, including Ag nanowires (AgNWs) [11], Au nanowires (AuNWs) [12], Cu nanowires (CuNWs) [13], and Pt nanowires [14]. Bicomponent metal nanowires, such as Cu@Ni [15], Ag@Au [16], Cu@Ag [17], Ag@Ni [18], and Cu@Pt [19] core@shell nanowires, have also been synthesized. These nanowires have been coated on a substrate to produce TCFs, and the performance has been characterized. At early stage of the research on metal nanowire TCFs, the transparency was lower than 80%, and the sheet resistance was as large as several kΩ to MΩ. Both experimental investigation and theoretical modeling have been extensively carried out to improve the performance of metal nanowire TCFs.
关键词： Core@shell nanowires,Transparent conductive films,Plasmonics,Electronics,Au nanowires,Metal nanowires,Ag nanowires,Cu nanowires,Electrocatalysis
更新于2025-09-23 15:21:21
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A chain is as strong as its weakest link – Stability study of MAPbI3 under light and temperature
摘要： The stability of perovskite solar cells is a key issue for industrial development. One reason for this is the volatile organic methylammonium (MA) cation, which is prone to degas under elevated temperatures from the perovskite. At the same time, small amounts of MA are used for practically all highest performing solar cells. These compositions have also shown relatively promising stabilities. This raises the question of MA stability with respect to different, application-dependent stability requirements. Interestingly, MA stability was mainly studied on thin films that differ from full devices or with architectures which are also prone to degrade. Therefore, the degradation behavior on complete MA containing devices with a relatively stable architecture is required to quantify the long-term stability of MA. This enables to determine at which timescales MA is unstable and which role it can play in future compositions. If MA is indeed unstable at much longer timescales than previously recorded, it also indicates that more severe degradation pathways are currently underappreciated. Here, “weakest link” MAPbI3 devices are used, i.e. showing promising stability: devices retained 100% of their initial efficiency over 1000 h of aging under constant illumination and maximum power point tracking at 20 °C. At elevated temperatures of 50 and 65 °C, the devices retained 100% and 90% of their initial efficiency after 500 h of illumination, respectively. Impressively, at 95 °C the MAPbI3 device retained 85% after 500 h under constant illumination of its initial efficiency, which is some of the best stability data reported to date for MA. Thus, MA-containing devices require further studying. Nevertheless to achieve the necessary industrial lifetimes of more than 25 years, the complete removal of MA is a sensible precaution to systematically avoid any long-term risk factors.
关键词： Electrocatalysis,Renewable energy,Metallic nanocrystals,Two-dimensional
更新于2025-09-23 15:21:01
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Puffing quaternary FexCoyNi1-x-yP nanoarray via kinetically controlled alkaline etching for robust overall water splitting; ?￠±???è???3??????oè?¨???FexCoyNi1a??xa??yP??????é?μ?????????é?? ???è￡?è§￡?°′??§è??;
摘要： Designing and constructing bifunctional electrocatalysts with high efficiency, high stability and low cost for overall water splitting to produce clean hydrogen fuel is attractive but highly challenging. Here we constructed puffed quaternary FexCoyNi1?x?yP nanoarrays as bifunctional electrodes for robust overall water splitting. The iron was used as the modulator to manipulate the electron density of NiCoP nanoarray, which could increase the positive charges of metal (Ni and Co) and P sites. The resultant electronic structure of FexCoyNi1?x?yP was supposed to balance the adsorption and desorption of H and accelerate the oxygen evolution reaction (OER) kinetics. Moreover, the morphological structure of FexCoyNi1?x?yP was modulated through the kinetically controlled alkaline etching by using the amphoteric features of initial FeCoNi hydroxide nanowires. The resultant puffed structure has rich porosity, cavity and defects, which benefit the exposure of more active sites and the transport of mass/charge. As a result, the cell integrated with the puffed quaternary FexCoyNi1?x?yP nanoarrays as both the cathode and anode only requires the overpotentials of 25 and 230 mV for hydrogen evolution reaction (HER) and OER at the current density of 10 mA cm?2 in alkaline media and a cell voltage of 1.48 V to drive the overall water splitting. Moreover, the puffed FexCoyNi1?x?yP demonstrates remarkable durability for continuous electrolysis even at a large current density of 240 mA cm?2.
关键词： water splitting,puffed nanoarray,electrocatalysis,morphology control,alkaline etching
更新于2025-09-23 15:21:01
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Plum Puddinga??Like Electrocatalyst of Na??Doped SnO <sub/><i>x</i> </sub> @Sn Loaded on Carbon Matrix to Construct Photovoltaic CO <sub/>2</sub> Reduction System with Solara??toa??Fuel Efficiency of 11.3%
摘要： A plum pudding-like Sn-based electrocatalyst is synthesized by calcinating precursor of SnC2O4 on carbon black with polymeric carbon nitride. This material exhibits a structure of Sn metallic ball coated by nitrogen-doped SnOx native layer (N-doped SnOx@Sn) embedding on carbon matrix. The electrochemical activity of the CN-Sn catalyst. The introduction of nitrogen that occupies interstitial space of surface SnOx layer further enhances electron transport; furthermore, it provides an electron-rich environment for oxygen because of its lower electronegativity, which is the fundamental cause of selectivity in electrochemical reduction of CO2 to CO. The maximum CO faradaic efficiency over the optimal catalyst reaches 57.5% with a high CO partial current density of 6.09 mA cm-2 at -0.7 V vs. RHE. This catalyst is further applied to construct a photovoltaic-electrocatalytic CO2 reduction/oxygen evolution reaction device to stably convert CO2 to chemicals for 6 hs at a high solar-to-fuel efficiency of 11.3%. This work explores a strategy of rational modulation on surface electronic structure to obtain high-performance electrocatalysts, inspiring the selectivity tuning in electrochemical CO2 reduction via electronegativity difference of various elements.
关键词： Sn,Doping,Electrocatalysis,Solar Energy Conversion,CO2 Reduction
更新于2025-09-23 15:19:57