Dual-function FeCo bimetallic nanoclusters for ammonia electrosynthesis from nitrate/nitrite reduction.

Ammonia (NH) plays a vital role in agriculture and chemical manufacturing, yet its conventional production is energy-intensive and environmentally harmful. Developing cleaner, more efficient alternatives is essential. Here we show a newly developed dual-metal nanocluster catalyst, FeCo/NC, that effectively converts nitrate and nitrite pollutants into NH through an electrochemical process.

Strategic Engineering of Axially Coordinated Ligands in Fe-N-C Catalysts for Enhanced Oxygen Reduction Electrocatalysis.

The single-atom Fe-N-C electrocatalyst is considered one of the most promising alternatives to the expensive and scarce Pt-based catalysts for promoting oxygen reduction reaction in fuel cells. Regulating the coordination environment of the Fe center is a feasible strategy to improve its stability and catalytic activity. Recently, the introduction of axial ligands to Fe-N-C has attracted extensive research interest, providing a new dimension for coordination environment regulation compared with the common approaches of in-plane doping or defect construction.

Efficient Photocatalytic Ethylene Oxidation to Acetaldehyde by Asymmetrical Dehydrogenation.

Acetaldehyde is an essential commodity chemical with high demand, while its conventional production by homogeneous Wacker oxidation suffers from high corrosivity, high chlorine by-products, and separation difficulties. In this work, a Pd nanoparticle-loaded ZnO (Pd-ZnO) photocatalyst is developed for the selective oxidation of ethylene to acetaldehyde. The ZnO substrate provides hydroxyl radicals (•OH) from water oxidation, and the Pd active sites allow to promote the dehydrogenation of adsorbed symmetrical ethylene to form asymmetrical vinyl specie (CH═CH) with negatively charged carbon, which can be further attacked by •OH to vinyl alcohol (CHOH) and finally undergo isomerization to produce acetaldehyde products.

Promoting Intermediate Stabilization and Coupling for Dimethyl Carbonate Electrosynthesis.

The electrocatalytic coupling of methanol and CO to produce dimethyl carbonate (DMC) is an attractive strategy for converting C resources into value-added products, while the controlled adsorption and coupling of two key intermediates, CO and OCH, have not been demonstrated yet. Herein, a heterointerface engineering strategy is developed to modulate intermediate adsorption and facilitate the C─O bond formation. By constructing a Pd and PdO heterostructure catalyst with abundant interfaces (designated as Pd/PdO-r), the Pd sites serve to stabilize CO and the electrophilic Pd sites can promote the OCH adsorption, thereby optimizing their spatial proximity and reactivity.

Perovskite heteroepitaxy for high-efficiency and stable pure-red LEDs.

Ultrasmall CsPbI perovskite quantum dots (QDs) are the most promising candidates for realizing efficient and stable pure-red perovskite light-emitting diodes (PeLEDs). However, it is challenging for ultrasmall CsPbI QDs to retain their solution-phase properties when they assemble into conductive films, greatly hindering their device application. Here we report an approach for in situ deposit stabilized ultrasmall CsPbI QD conductive solids, by constructing CsPbI QD/quasi-two-dimensional (quasi-2D) perovskite heteroepitaxy.

Managing Edge States in Reduced-Dimensional Perovskites for Highly Efficient Deep-Blue LEDs.

Pure-halide reduced-dimensional perovskites, featuring large exciton binding energy and tunable bandgap, show great potential for high-efficiency deep-blue perovskite light-emitting diodes (PeLEDs). However, their efficiency, particularly in the low n-value phase domain ("n" represents the number of octahedral sheets), lags behind analogous perovskite emitters. Herein, it is demonstrated that the vibration of edge-dangling octahedra in the low n-value phase activates notorious exciton-phonon (EP) coupling, thereby deteriorating efficiency.

A Hypothesis on the Function of High-Valent Fe in NiFe (Hydr)oxide in the Oxygen-Evolution Reaction.

This study investigated the dynamic changes in NiFe (hydr)oxide and identified the role of high-valent Fe in the oxygen-evolution reaction (OER) within alkaline media via in situ techniques. Several high-valent Fe ions were found to remain considerably stable in the absence of potential in NiFe (hydr)oxide, even 96 hours after the OER. For Ni hydroxide treated with Fe ions, where Fe sites are introduced onto the surface of Ni hydroxide, no Fe species were detected at the rate-determining step (RDS).

Electrokinetic Analysis-Driven Promotion of Electrocatalytic CO Reduction to n-Propanol.

The electrocatalytic carbon dioxide or carbon monoxide reduction reaction (CORR or CORR) features a sustainable method for reducing carbon emissions and producing value-added chemicals. However, the generation of C products with higher energy density and market values, such as n-propanol, remains highly challenging, which is attributed to the unclear formation mechanism of C versus C products. In this work, by the Tafel slope analysis, electrolyte pH correlation exploration, and the kinetic analysis of CO partial pressure fitting, it is identified that both n-propanol and C products share the same rate-determining step, which is the coupling of two C intermediates via the derivation of the Butler-Volmer equation.

Promoting CO Electroreduction to C Oxygenates by Distribution of Water Dissociation Sites.

The electrocatalytic CO or CO reduction reaction is a complex proton-coupled electron transfer reaction, in which protons in the electrolyte have a critical effect on the surface adsorbed H species and the multi-carbon oxygenate products such as ethanol. However, the coupling of H and carbon-containing intermediates into C oxygenates can be severely hampered by the inappropriate distributions of those species in the catalytic interfaces. In this work, the controlled distribution of highly dispersed CeO nanoclusters is demonstrated on Cu nanosheets as an efficient CO electroreduction catalyst, with Faradaic efficiencies of ethanol and total oxygenates of 35% and 58%, respectively.

Electrocatalytic Glycerol Upgrading into Glyceric Acid on NiSn Intermetallic Compound.

Electrochemical glycerol oxidation features an attractive approach of converting bulk chemicals into high-value products such as glyceric acid. Nonetheless, to date, the major product selectivity has mostly been limited as low-value C products such as formate, CO, and CO, due to the fast cleavage of carbon-carbon (C-C) bonds during electro-oxidation. Herein, the study develops an atomically ordered NiSn intermetallic compound catalyst, in which Sn atoms with low carbon-binding and high oxygen-binding capability allow to tune the adsorption of glycerol oxidation intermediates from multi-valent carbon binding to mono-valent carbon binding, as well as enhance OH binding and subsequent nucleophilic attack.

Bipolaronic Motifs Induced Spatially Separated Catalytic Sites for Tunable Syngas Photosynthesis From CO.

Photocatalytic reduction of CO into syngas is a promising way to tackle the energy and environmental challenges; however, it remains a challenge to achieve reaction decoupling of CO reduction and water splitting. Therefore, efficient production of syngas with a suitable CO/H ratio for Fischer-Tropsch synthesis can hardly be achieved. Herein, bipolaronic motifs including Co(II)-pyridine N motifs and Co(II)-imine N motifs are rationally designed into a crystalline imine-linked 1,10-phenanthroline-5,6-dione-based covalent organic framework (bp-Co-COF) with a triazine core.

Tailoring the CO and H Coverage for Selective CO Electroreduction to CH or CH.

In the electrochemical CO reduction reaction (CORR), the coverages of CO and H intermediates on a catalyst surface are critical for the selective generation of C or C products. In this work, we have synthesized several CuZnMn ternary alloy electrocatalysts, including CuZnMn, CuZnMn, and CuZnMn, by varying the doping compositions of Zn and Mn, which are efficient in binding CO and H adsorbates in the CO electroreduction process, respectively. The increase of H coverage allows to promotion of the CH and H formation, while the increase of the CO coverage facilitates the production of CH and CO.

Tuning the Electronic Properties of Platinum in Hybrid-Nanoparticle Assemblies for use in Hydrogen Evolution Reaction.

Platinum is the best electrocatalyst for the hydrogen evolution reaction (HER). Here, we demonstrate that by contact electrification of Pt nanoparticle satellites on a gold or silver core, the Fermi level of Pt can be tuned. The electronic properties of Pt in such hybrid nanocatalysts were experimentally characterized by X-ray photoelectron spectroscopy (XPS) and surface-enhanced Raman scattering (SERS) with the probe molecule 2,6-dimethyl phenyl isocyanide (2,6-DMPI).

Electrocatalytically Activating and Reducing N Molecule by Tuning Activity of Local Hydrogen Radical.

Decarbonizing N conversion is particularly challenging, but essential for sustainable development of industry and agriculture. Herein, we achieve electrocatalytic activation/reduction of N on X/Fe-N-C (X=Pd, Ir and Pt) dual-atom catalysts under ambient condition. We provide solid experimental evidence that local hydrogen radical (H*) generated on the X site of the X/Fe-N-C catalysts can participate in the activation/reduction of N adsorbed on the Fe site.

Light inhibition of hydrogenation reactions on Au-Pd nanocoronals as plasmonic switcher in catalysis.

Light, as a powerful energy source, has motivated the many endeavors of chemists in photochemical transformations. We were delighted to find that light has an inhibition effect on hydrogenation reactions. Exploring this previously unperceived effect will bring renewed understanding of interactions of light and matter.

Interfacial Evolution on Co-based Oxygen Evolution Reaction Electrocatalysts Probed by Using Surface-Enhanced Raman Spectroscopy.

Disclosing the roles of reactive sites at catalytic interfaces is of paramount importance for understanding the reaction mechanism. However, due to the difficulties in the detection of reaction intermediates in the complex heterophase reaction system, disentangling the highly convolved roles of different surface atoms remains challenging. Herein, we used CoO as a model catalyst to study the synergy of Co and Co active sites in the electrocatalytic oxygen evolution reaction (OER).

Several Key Factors for Efficient Electrocatalytic Water Splitting: Active Site Coordination Environment, Morphology Changes and Intermediates Identification.

Water-splitting has emerged as a promising alternative strategy to produce clean hydrogen fuel. However, current electrocatalytic water splitting suffers from sluggish kinetics, thus developing efficient electrocatalysts is crucial. Identifying reaction centers discloses the reaction mechanism and will undoubtedly facilitate the design and optimization of efficient water splitting electrocatalysts.

Surface-Enhanced Raman Spectroscopic Evidence of Key Intermediate Species and Role of NiFe Dual-Catalytic Center in Water Oxidation.

NiFe-based electrocatalysts have attracted great interests due to the low price and high activity in oxygen evolution reaction (OER). However, the complex reaction mechanism of NiFe-catalyzed OER has not been fully explored yet. Detection of intermediate species can bridge the gap between OER performances and catalyst component/structure properties.

Dendrite-Free Lithium Deposition via a Superfilling Mechanism for High-Performance Li-Metal Batteries.

Uncontrollable Li dendrite growth and low Coulombic efficiency severely hinder the application of lithium metal batteries. Although a lot of approaches have been developed to control Li deposition, most of them are based on inhibiting lithium deposition on protrusions, which can suppress Li dendrite growth at low current density, but is inefficient for practical battery applications, with high current density and large area capacity. Here, a novel leveling mechanism based on accelerating Li growth in concave fashion is proposed, which enables uniform and dendrite-free Li plating by simply adding thiourea into the electrolyte.

Surface Restraint Synthesis of an Organic-Inorganic Hybrid Layer for Dendrite-Free Lithium Metal Anode.

Li metal is considered to be the most attractive anode for next-generation batteries because of its high specific capacity and low reduction potential. However, uncontrolled Li dendrite growth and low Coulombic efficiency cause severe capacity decay and safety issues. Here we propose a LiCl contained inorganic-organic hybrid layer on Li metal surface by a surface restraint dehalogenation reaction, which is highly uniform and features lithiophilic property as well as high ionic conductivity that can inhibit Li dendrite growth effectively.

Polyvinylchloride-derived N, S co-doped carbon as an efficient sulfur host for high-performance Li-S batteries.

The intrinsic polysulfide shuttle in lithium-sulfur (Li-S) batteries have significantly limited their practical applications. Conductive carbon materials with heteroatom doping and rich porosity is the most common strategy for the effective prevention of polysulfide shuttle, but are usually obtained with high costs and tedious procedures. Herein, we managed to obtain highly porous N, S-codoped carbon materials (NS-C) through treating waste plastic of polyvinylchloride (PVC) with KOH.

Polymer Dehalogenation-Enabled Fast Fabrication of N,S-Codoped Carbon Materials for Superior Supercapacitor and Deionization Applications.

Doped carbon materials (DCM) with multiple heteroatoms hold broad interest in electrochemical catalysis and energy storage but require several steps to fabricate, which greatly hinder their practical applications. In this study, a facile strategy is developed to enable the fast fabrication of multiply doped carbon materials via room-temperature dehalogenation of polyvinyl dichloride (PVDC) promoted by KOH with the presence of different organic dopants. A N,S-codoped carbon material (NS-DCM) is demonstratively synthesized using two dopants (dimethylformamide for N doping and dimethyl sulfoxide for S doping).