Advanced Sensor and Energy Materials最新文献

Electrocatalytic CO₂ reduction reaction (CO₂RR) is one of the effective means to realize CO₂ resource utilization. Among the high-efficiency metal-based catalysts, Cu is a star material profiting from its ability for CO₂ reduction into valuable hydrocarbon products. However, due to the difficulty in activating CO₂ and regulating intermediate adsorption/desorption properties, the CO₂RR activity and selectivity of Cu-based catalysts still cannot meet the requirements of industrial applications. The design of Cu-based bimetallic catalysts is a potential strategy because the introduction of the second metal can well promote the activation of CO₂ and break the linear scaling relationship in intermediate adsorption/desorption. In this review, the synergistic enhancements of Cu-based bimetals on CO₂ activation and intermediate adsorption/desorption are analyzed in detail, including the advantages caused by the morphology of Cu-based bimetallic catalysts, the local electric field effect induced by the special nanoneedle structure, the interface engineering (strain effect, atomic arrangement, interface regulation), and other particular effects (electronic effect and tandem effect). Finally, the challenges and perspectives on the development of Cu-based bimetallic catalysts for CO₂ reduction are proposed.

Interface engineering is deemed as an effective approach to optimize the electronic structure of catalytically active sites in electrocatalysts for boosted hydrogen evolution reaction (HER). Herein, a novel ultrasmall VN/Co heterostructure anchored in N-doped graphitized nanocarbons (VN/Co@GNC) is successfully synthesized by a simple calcination protocol. Benefiting from the abundant reactive sites on the interface of ultrasmall heterostructure, enhanced N active sites of VN coupled with Co nanoparticles, as well as excellent conductivity of N-doped graphitized nanocarbons as the scaffold, the resulting VN/Co@GNC material exhibits outstanding electrocatalytic HER performance, delivering the current density of 10 mA/cm² at a quite low overpotential of 155 mV without iR-compensation, and retaining the catalytic durability for at least 565 h (∼23.5 days) in 1 M KOH solution. The superior catalytic activity and ultrastability of VN/Co@GNC electrocatalyst lay a solid foundation for its commercial applications toward the hydrogen fuel production.

A fundamental understanding of ion transport at the nanoscale is critical to the development of efficient chemical separation membranes, catalysts, ionic/bio-inspired materials, and its scale up into multi-functional ionic devices. Electrochemical imaging using scanning probe microscopy hardware has provided a method to visualize and understand processes that occur at the surface of ionic active materials. The suite of scanning probe microscopy techniques developed over the last few years are limited to imaging surface-level phenomena and have not been applied to investigate transmembrane properties of synthetic and natural membranes with high spatial and temporal resolution. In this article, we demonstrate the application our recently developed ‘surface-tracked scanning ion conductance microscopy’ technique to characterize voltage-regulated ion transport in an ionic redox transistor. The ionic redox transistor exhibits controlled transmembrane ion transport as a function of its electrochemical redox state. The technique presented in this article uses shear force measured between the nanopipette and ionic substrate to image topography of the porous substrate and simultaneously characterize topography-correlated transmembrane transport through the ionic redox transistor. The transmembrane conductance measured across an array of pores within the ionic redox transistor varies from 0.004 μS/cm (OFF state) to 0.015 μS/cm (ON state). We anticipate that the spatial correlation of transmembrane ion transport in the ionic redox transistor would result in a scale up into smart membrane separators for energy storage, neuromorphic circuits, and desalination membranes.

Nanozymes, a class of nanomaterials that exhibit enzyme-like characteristics in catalysis, have been booming over decades. They feature unique properties, such as low cost, high chemical stability, easy storage, and highly tunable reactivity. Nanozymes with biomolecule modifications received the most attention because of their high biocompatibility and better natural enzyme-mimicking. With their unique physicochemical properties, these biomolecule nanohybrids have been used in a variety of applications. Hence, we highlight the current progress for “biohybrid nanozymes” in this review. The synthesis, composition, and catalytic performances of different biohybrid nanozymes are discussed. We expect that biohybrid nanozymes will attract broad interest in fundamental research and practical applications.

Metal organic frameworks derived M-N-C catalysts have been discovered as promising alternatives to Pt-based catalysts in oxygen reduction reaction (ORR). However, the dominated micropores in their porous structures strongly restrain the mass transfer and lead to insufficient utilization of active sites. Here, we proposed a dual-template strategy to improve the catalytic performance of ZIF-8 derived M-N-C catalysts. Both the silica and sodium chloride templates created mesopores, which may intensified the mass transfer. Moreover, the molten sodium chloride connected the individual ZIF-8 crystals form highly graphitized carbon structure which had better stability and conductivity. The as-synthesized (FeCo)HPNC@NaCl catalyst exhibited similar ORR activity to commercial Pt/C under acidic conditions with half-wave potential of 0.808 V. The catalyst expressed high stability with 12 mV decrease of half-wave potential after 5000 cycles and 80% remained activity after 100000 s operation. Moreover, we tested the catalyst in fuel cell for practical application, achieving a high peak power density of 427 mW cm⁻².

Photo-induced selective shortening strategy was developed to synthesize Au nanorods (NRs) with different aspect ratios, and in situ observation of photo-induced shortening of single Au nanorod was realized, which is helpful for understanding the relationship between SPR decay and geometric nanostructure. The as-synthesized plasmonic Pd–Au NRs exhibit efficient formic acid dehydrogenation. Very impressively, the interfacial interaction between plasmonic bimetallic nanostructures and adsorbed molecules (HCOOH) was explored in situ at the single-particle level. Significant photoluminescence (PL) quenching of Pd–Au NRs was observed when HCOOH contacted the catalyst, confirming the charge transfer between Pd–Au NRs and HCOOH molecules. Finally, we shed light on the catalytic mechanism of plasmon-induced HCOOH dehydrogenation by coupling single-particle PL measurement with finite difference time domain (FDTD) and density functional theory (DFT) calculations.

Recently, ammonium-ion (NH₄⁺) storage is in a booming stage in aqueous energy storage systems due to its multitudinous merits. To seek suitable electrode materials with excellent NH₄⁺-storage is still in the exploratory stage and full of challenge. Herein, an inorganic-polymer hybrid, poly(3,4-ethylenedioxithiophene) (PEDOT) intercalated hydrated vanadium oxide (VOH), named as VOH/PEDOT, is developed to tune the structure of VOH for boosting NH₄⁺ storage. By the intercalation of PEDOT, the interlayer space of VOH is increased from 11.5 Å to 14.2 Å, which notably facilitates the rapid transport of electrons and charges between layers and improves the electrochemical properties for NH₄⁺ storage. The achieved performances are much better than progressive NH₄⁺ hosting materials. In addition, the concentration of polyvinyl alcohol/ammonium chloride (PVA/NH₄Cl) electrolyte exerts a great impact on the NH₄⁺ storage in VOH/PEDOT. The VOH/PEDOT electrode delivers specific capacitance of 327 F g⁻¹ in 1 M PVA/NH₄Cl electrolyte at −0.2–1 V. Furthermore, the quasi-solid-state VOH/PEDOT//active carbon hybrid supercapacitor (QSS VOH/PEDOT//AC HSC) device is assembled for NH₄⁺ storage, and it exhibits the capacitance of 328 mF cm⁻² at 1 mA cm⁻². The energy density of QSS VOH/PEDOT//AC NH₄⁺-HSC can reach 2.9 Wh m⁻² (2.6 mWh cm⁻³, 10.4 Wh kg⁻¹) at 1 W m⁻² (0.9 mWh cm⁻³, 35.7 W kg⁻¹). This work not only proves that the PEDOT intercalation can boost the NH₄⁺ storage capacity of vanadium oxides, but also provides a novel direction for the development of NH₄⁺ storage materials.

Electrochemical energy storage and conversion toward sustainable carbon neutrality cycle is of great interest in today's society. In this perspective, we highlight the interconversion between carbon dioxide and formic acid by means of electrocatalytic CO₂ reduction reaction (CO₂RR) and formic acid oxidation reaction (FAOR) as an effective way to achieve that goal. In line with the distinctive catalytic nature of Pd to reversibly drive both FAOR and CO₂RR, we first illustrate the intimate mechanistic relation between these two reversed reactions over Pd surfaces. Next, recent advances in developing Pd-based bifunctional catalysts and relevant optimization strategies are briefly summarized, including geometric structure engineering with preferential facet exposure, construction of crystallographic ordering intermetallic, electronic structure manipulation through metal or metalloid doping to fine tune the binding strength for active and poisoning intermediates. At the end, our viewpoints on the design principles at both microscopic and macroscopic scales are offered toward an efficient CO₂ and HCOOH interconversion loop.