摘要 : We fabricated a multidimensional heterostructured In2S3–CuInS2 photocatalyst to convert CO2 to CO. The hybrid photocatalyst can be obtained by using an In-containing MOF as a precursor followed by sulfidation and ion exchange. Moreover, the multidimensional structure, a 2D nanosheet semiconductor distributed on 1D hollow nanotubes, inhibits the recombination of charge carriers, increases CO2 adsorption and affords a large surface area promoting exposure of plentiful active sites. As a result, the as-synthesized optimal heterostructured In2S3–CuInS2 display a excellent activity with the CO evolution rate of 19.00 μmol g−1 h−1 over the under visible light irradiation, which is roughly four times higher than that of pristine In2S3. This work might pave the way for increasing the performance of metal sulphide photocatalysts by MOF-guided chemistry.

摘要 : The design and synthesis of highly efficient thermally activated delayed fluorescence (TADF) emitters with an electroluminescence wavelength beyond 600 nm remains a great challenge for organic light-emitting diodes (OLEDs). To solve this issue, three TADF molecules, xDMAC–BP (x = 1, 2, 3), are developed in combination with the rigid planar dibenzo[a,c]phenazine (BP) acceptor core and different numbers of 9,9-dimethylacridan (DMAC) donors. All these emitters possess stable internal charge transfer and a large dihedral angle between the donors and planar BP core. The emission wavelength can be regulated from 541 to 605 nm by increasing the number of the donor DMAC units because of the controllable tuning of the intramolecular charge transfer effect and the molecular geometrical structure. The photoluminescence quantum yields of these emitters are improved from 42 to 89% with the increase in the number of DMAC units. The orange-red OLEDs employing the xDMAC–BP emitters exhibit maximum external quantum efficiency (EQE) of 22.0% at 606 nm, which is the highest EQE of the previously reported TADF OLEDs exceeding 600 nm.

摘要 : The exploration of non-noble metal catalysts toward the electrochemical nitrogen reduction reaction (NRR) is crucial for industrial-scale ammonia synthesis. Although metal sulfides have long been predicted to be electrocatalytically more efficient than other compounds, there has been no substantial progress made on them due to the difficulties in the controllable synthesis of elaborate nanostructures with optimized NRR performance. Besides, their inferior electrical conductivity is not favorable for electrocatalysis. Herein, we propose an interesting conceptual design to integrate novel metal sulfide catalysts with a fascinating conductive matrix. Through self-organized growth under solvothermal conditions, flower-like SnS2 and forest-like ZnS nanoarrays are directly formed on Ni foam with intimate adhesion. Both SnS2 and ZnS exhibit remarkable abilities in nitrogen activation, which are further enhanced by forming well-aligned nanoarrays on 3D porous Ni foam, offering a large surface area and enabling easy electrolyte permeation. Moreover, Ni foam significantly outperforms carbonaceous materials as a conductive matrix because of its far better electrical conductivity and mechanical robustness. The resulting SnS2@Ni and ZnS@Ni foams show synergistic superiority as advanced hybrid catalysts, delivering high ammonia yields and faradaic efficiencies comparable to or even better than those of noble-metal-based catalysts.

摘要 : Direct electrochemistry, a direct electron transfer process between enzymes and electrode possesses, has important fundamental significance in bioelectrochemistry while offering very efficient electrocatalysis for enzyme-based sensors. Herein, the pore structure of bacterial cellulose porous carbon nanofibers (BPCNFs) is tailored by controlled thermal carbonization. It is discovered that rising mesopores can realize a fast direct electrochemistry of glucose oxidase (GOx) for highly sensitive detection of glucose, achieving a sensitivity of 123.28 µA mmol L−1 cm−2 and a detection limit of 0.023 µmol L−1. The enhancement mechanism for the mesopores is ascribed to the most adequate mesopores of BPCNF900, which offer size-matched “nests” to trap GOx for intimate contacts with the conductive carbon nanofiber enabling fast direct electrochemistry. In addition, with the BPCNF900 sensing platform, the mechanisms for GOx-direct-electrochemistry-catalyzed glucose oxidation and oxygen reduction are systematically investigated to further clarify the confusions of glucose sensing in air and N2-saturated solutions. This work demonstrates fundamental insights for the direct electrochemistry enabled by rationally designing a pore structure matching the target proteins, thus possessing universal significance in protein-based electrochemical devices while offering a facile route to fabricate a highly sensitive glucose sensor for practical clinic diagnosis.

摘要 : Developing cost-effectiveness and superior electrocatalysts is crucial to improve the efficiency of oxygen evolution reaction (OER) in water splitting system. Hence, flower-like phosphorus doped Ni 3 S 2 /CoFe 2 O 4 arrays (P-Ni 3 S 2 /CoFe 2 O 4 /NF) were generated on three-dimensional (3D) nickel foam (NF) via the two-step hydrothermal treatment and subsequent phosphorization. Additionally, a series of control experiments were conducted to investigate the formation mechanism. By virtue of the unique 3D configurations and multi-compositions, the as-prepared catalyst exhibited greatly improved OER performance in 1.0 M KOH solution, with the overpotential of only 254 mV at 50 mA cm −2 and low Tafel slope of 54.43 mV dec −1 . This study provides a feasible approach for preparing advanced electrocatalyst in energy conversion and storage devices.

摘要 : Porous gold nanosheets modified glassy carbon electrode (GCE) was facilely prepared by one-step electrodeposition, using N-methylimidazole as a growth-directing agent. The porous gold nanosheets modified GCE was characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction spectroscopy. The modified electrode displayed improved sensitivity for individual and simultaneous differential pulse voltammetric determination of dopamine (DA; at 180 mV) and acetaminophen (AC; at 450 mV vs. Ag/AgCl) even in the presence of ascorbic acid. The oxidation peak currents linearly increased with the concentrations of DA and AC in the ranges from 2.0 to 298.0 μM and 3.0 to 320.0 μM, respectively, and the detection limits are 0.28 μM for DA and 0.23 μM for AC. The relative standard deviations (n = 20) are 1.5 % for DA and 0.4 % for AC. A simple method was developed for simultaneous detection of dopamine and acetaminophen with high sensitivity on porous gold nanosheets modified glassy carbon electrodes.

摘要 : Binding strength of reactive intermediates with catalytically active sites plays a crucial role in governing catalytic performance of electrocatalysts. NiFe hydroxide offers efficient oxygen evolution reaction (OER) catalysis in alkaline electrolyte, however weak binding of oxygenated intermediates on NiFe hydroxide still badly limits its catalytic activity. Herein, we developed a facile ball-milling method to enhance binding strength of NiFe hydroxide to oxygenated intermediates via generating tensile strain, which reduced the anti-bonding filling states in the d orbital and thus facilitated oxygenated intermediates adsorption. The NiFe hydroxide with tensile strain increasing after ball-milling exhibits an OER onset potential as low as 1.44 V (vs. reversible hydrogen electrode) and requires only a 270 mV overpotential to reach a water oxidation current density of 10 mA cm-2.

摘要 : Unique layered and heterostructured Pd/PdWCr nanosheet‐assembled flowers (L‐Pd/PdWCr) are successfully synthesized, resulting in the most negative onset potential (up to −0.174 V vs SCE) for formic acid oxidation among all reported Pd‐based electrocatalysts. It has 4.3‐times higher catalytic peak current density and better stability than that of the commercial Pd/C. The catalytic enhancement mechanism is mainly due to the synergetic effect of the layered and heterostructures of the Pd/PdWCr nanosheet. The W‐ and Cr‐tailored Pd/PdWCr heterostructures optimize the electronic structure of Pd with suitable binding energy to reduce the charge‐transfer resistance. Moreover, the layered nanosheet‐assembled flowers provide easily accessible large surface area and rapid mass transport path. The great stability can be attributed to the reduced total free energy resulting from the layered structure and the highly stable structure formed by the cross‐linked flower skeleton and suppressed Pd dissolution with W and Cr. This work provides an inexpensive, highly active, and stable anode electrocatalyst for direct formic acid fuel cells while demonstrating a method to synthesize layer‐structured metal alloy catalysts.

摘要 : Herein, a unique ganoderma-like MoS2/NiS2 hetero-nanostructure with isolated Pt atoms anchored is reported. This novel ganoderma-like heterostructure can not only efficiently disperse and confine the few-layer MoS2 nanosheets to fully expose the edge sites of MoS2, and provide more opportunity to capture the Pt atoms, but also tune the electronic structure to modify the catalytic activity. Because of the favorable dispersibility and exposed large specific surface area, single Pt atoms can be easily anchored on MoS2 nanosheets with ultrahigh loading of 1.8 at% (the highest is 1.3 at% to date). Owing to the ganoderma-like structure and platinum atoms doping, this catalyst shows Pt-like catalytic activity for the hydrogen evolution reaction with an ultralow overpotential of 34 mV and excellent durability of only 2% increase in overpotential for 72 h under the constant current density of 10 mA cm−2.

摘要 : Aqueous zinc-ion batteries (ZIBs), due to their sluggish Zn2+ diffusion kinetics, continue to face challenges in terms of achieving superior high rate, long-term cycling and low-temperature properties. Herein, K+ pre-intercalated layered V2O5 (K0.5V2O5) composites with metallic features are capable of delivering excellent zinc storage performance. Specifically, the K0.5V2O5 electrode delivers a high reversible capacity of 251 mA h g−1 at 5 A g−1 after 1000 cycles. Even at a low temperature of −20 °C, high reversible capacities of 241 and 115 mA h g−1 can be obtained after 1000 cycles at 1 and 5 A g−1, respectively. The outstanding electrochemical performance is attributed to the incorporation of K+ into the layered V2O5, which acts as pillars to promote the Zn2+ diffusion and increase the structural stability during cycling. Density functional theory calculations demonstrate that the interlayer doping of K+ can benefit electron migration, and therefore enhance the Zn2+ (de)intercalation kinetics. Meanwhile, the Zn2+ storage mechanism of K0.5V2O5 is revealed by ex situ X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy characterization. This work may pave the way for exploiting high-performance cathodes for aqueous ZIBs.