Insights into free radical and non-radical routes regulation for water cleanup.

In the field of wastewater treatment, the regulation of free radical and non-radical routes has been one of the major challenges. This study investigates the regulation of radical and non-radical oxidation pathways in the peroxymonosulfate (PMS) oxidation system by controlling the calcination temperature of carbon materials and constructing bimetallic single-atom catalysts (NC-FeMn(TA)). Density functional theory calculations and experimental tests indicate that increasing the pyridinic nitrogen content and incorporating single metal atoms in nitrogen-doped carbon materials result in a predominantly non-radical oxidation process.

Acidic oxygen reduction by single-atom Fe catalysts on curved supports.

Developing highly active and durable electrocatalysts for cost-effective proton-exchange membrane fuel cells is challenging. Fe/N-C catalysts are among the most promising alternatives to the platinum group metal catalysts, but their activity and durability still cannot meet the performance criteria due to the strong adsorption of oxygenated reaction intermediates and the demetallization of Fe species caused by the Fenton reaction. Here we design and develop a new type of Fe/N-C catalyst that is composed of numerous nanoprotrusions dispersed on two-dimensional carbon layers with single Fe-atom sites primarily embedded within the inner curved surface of the nanoprotrusions.

Efficient Regeneration of Waste Styrene Adsorption Carbon Catalyzed by Spinel NiCoO Active Sites and Cyclic VOC Adsorption and Desorption Performance.

During thermal regeneration of styrene-saturated activated carbon (AC), styrene's C=C bonds are prone to polycondensation. It forms fixed carbon species that deposit as carbonaceous residues within AC pores, significantly decreasing the adsorption performance. To address this challenge for efficient AC regeneration and recycling, Ni and Co transition metal components were loaded onto AC and subsequently pyrolyzed to generate NiCoO active species.

S-doped Ag-Sn Alloy Hollow Microbox for High-Performance CO Electroreduction to Formate.

The dynamic catalyst's restructuring creates a new catalytic surface that is essential for boosting the efficiency of electrochemical carbon dioxide reduction reaction (CORR). In this work, we synthesize Ag-decorated SnS hollow microboxes using a coprecipitation method followed by a hydrothermal treatment. Based on a collection of in-situ/ex-situ characterizations including in-situ Raman spectroscopy, rapid freeze-quench (RFQ) Sn Mössbauer spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), we discover that the Ag-decorated SnS (Ag@SnS) hollow microboxes undergo dynamic reduction and reconstruction during the electrochemical CORR, leading to the in-situ formation of S-doped Ag-Sn alloy (S-AgSn/Sn) hollow microboxes.

On the Coordination Environment of Single-Atom Catalysts.

ConspectusSingle-atom catalysis has become one of the most active frontiers in catalysis in the past decade. This concept not only gives birth to a new kind of heterogeneous catalysts featuring well-defined isolated active sites and strong covalent (or electronic) metal-support interaction, which deliver unique catalytic activity, selectivity, and stability distinct from their nanoparticulate counterparts, but also together with the principles and concepts in history, reshapes our understanding of heterogeneous catalysis and drives the catalysis research from the nanoscale and subnanoscale to the more precise atomic scale.Due to the extremely high free energy, the isolated gaseous metal atoms cannot survive alone but are stabilized on the support materials through strong chemical binding, forming metal-centered coordination moieties resembling organometallics in homogeneous catalysis.

Design Principles of Single-Atom Catalysts for Electrocatalytic CO Reduction to High-Value Hydrocarbons.

The CO electrochemical reduction (CORR) is regarded as a promising approach to mitigate carbon emissions while producing valuable chemical feedstocks and fuels. Among the possible products, multi-carbon (C) compounds such as ethylene and ethanol are highly desirable due to their higher energy density and industrial relevance. Recently, single-atom catalysts (SACs) have emerged as a powerful class of electrocatalysts in CORR, offering high atomic efficiency and tunable active sites.

Asymmetric tacticity navigates the localized metal spin state for sustainable alkaline/sea water oxidation.

Anodic oxygen evolution reaction (OER) that involves a spin-dependent singlet-to-triplet oxygen changeover largely restrains the water electrolysis efficiency for hydrogen production. However, the modulation of spin state is still challengeable for most OER catalysts, and there remains a debate on deciphering the active spin state in OER. Here, we pioneered an asymmetric Fe-incorporated NiPS tactic system to retune the metal localized spin for efficient OER electrocatalysis.

Chemical looping synthesis of amines from N via iron nitride as a mediator.

Amines are commonly synthesized through the amination of organooxygenates using ammonia, frequently involving the use of noble metal catalysts. In this study, we present an alternative route to make amines using iron nitride (FeN) as the nitrogen source. Without any additional catalyst, FeN reacts with a range of alcohols at 250 °C under 1 or 10 bar H to produce amines as major products.

Manipulating C-C coupling pathway in electrochemical CO reduction for selective ethylene and ethanol production over single-atom alloy catalyst.

Manipulation C-C coupling pathway is of great importance for selective CO electroreduction but remain challenging. Herein, two model Cu-based catalysts, by modifying Cu nanowires with Ag nanoparticles (AgCu NW) and Ag single atoms (AgCu NW), respectively, are rationally designed for exploring the C-C coupling mechanisms in electrochemical CO reduction reaction (CORR). Compared to AgCu NW, the AgCu NW exhibits a more than 10-fold increase of C selectivity in CO reduction to ethanol, with ethanol-to-ethylene ratio increased from 0.

Frustrated Lewis Pairs from Al-E Bonds (E=Ge, Sn, Pb).

The potassium aluminyl K[Al(NON)] ([NON]=[O(SiMeNDipp)], Dipp=2,6-iPrCH) reacts with group 14 chloroamidinates E(Am)Cl (E=Ge, Sn, Pb. [Am]=[tBuC(NDipp)]) to form (NON)Al-E(Am) Lewis pairs with unsupported Al-E bonds, including the first structurally authenticated Al-Pb bond. Analysis using spectroscopic (NMR, UV-vis and Mössbauer for E=Sn), X-ray diffraction and computational (DFT, QTAIM, TD-DFT) methods conclude an Al-E σ-bond derived from a Lewis basic Al and a Lewis acidic tetrylene, with back-donation from the E s-orbital lone pair donor NBO to acceptor NBOs on Al that are derived from s/p-orbitals.

Modulating Spin of Atomic Manganese Center for High-Performance Oxygen Reduction Reaction.

Single atom catalysts (SACs) are promising non-precious catalysts for oxygen reduction reaction (ORR). Unfortunately, the ORR SACs usually suffer from unsatisfactory activity and in particular poor stability. Herein, we report atomically dispersed manganese (Mn) embedded on nitrogen and sulfur co-doped graphene as an efficient and robust electrocatalyst for ORR in alkaline electrolyte, realizing a half-wave potential (E) of 0.

Visualizing Catalytic Dynamics of Single-Cu-Atom-Modified SnS in CO Electroreduction via Rapid Freeze-Quench Mössbauer Spectroscopy.

Effective design and engineering of catalysts for an optimal performance depend extensively on a profound understanding of the intricate catalytic dynamics under reaction conditions. In this work, we showcase rapid freeze-quench (RFQ) Mössbauer spectroscopy as a powerful technique for quantitatively monitoring the catalytic dynamics of single-Cu-atom-modified SnS (Cu/SnS) in the electrochemical CO reduction reaction (CORR). Utilizing the newly established RFQ Sn Mössbauer methodology, we clearly identified the dynamic transformation of Cu/SnS to Cu/SnS and Cu/Sn during the CORR, resulting in an outstanding Faradaic efficiency for formate production (∼90.

Open-cage metallo-azafullerenes as efficient single-atom catalysts toward oxygen reduction reaction.

Very recently, open-cage metallo-azafullerenes PbC100N4H4 and Pb2C100N4H4 containing one Pb-N4-C moiety have been synthesized via the electron beam. Herein, we utilized density functional theory calculations in combination with ab initio molecular dynamics (AIMD) simulations to study the geometric and electronic structures, bonding properties, thermodynamic stability, and catalytic performance of MC100N4H4 and M2C100N4H4 (M = Ge, Sn, Pb). Metal-nitrogen distances and metal-metal distances increase along with the metal radius while the metal atom is positively charged.

Waxberry-like hydrophilic Co-doped ZnFeO as bifunctional electrocatalysts for water splitting.

Water splitting is a promising technique for clean hydrogen production. To improve the sluggish hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), the development of efficient bifunctional electrocatalysts for both HER and OER is urgent to approach the scale-up applications of water splitting. Nowadays transition metal oxides (TMOs) are considered as the promising electrocatalysts due to their low cost, structural flexibility and stability, however, their electrocatalytic activities are eager to be improved.

Vacancy Defects Inductive Effect of Asymmetrically Coordinated Single-Atom Fe─N S Active Sites for Robust Electrocatalytic Oxygen Reduction with High Turnover Frequency and Mass Activity.

The development of facile, efficient synthesis method to construct low-cost and high-performance single-atom catalysts (SACs) for oxygen reduction reaction (ORR) is extremely important, yet still challenging. Herein, an atomically dispersed N, S co-doped carbon with abundant vacancy defects (NSC-vd) anchored Fe single atoms (SAs) is reported and a vacancy defects inductive effect is proposed for promoting electrocatalytic ORR. The optimized catalyst featured of stable Fe─N S active sites exhibits excellent ORR activity with high turnover frequency and mass activity.

Mössbauer Spectroscopic Tracking the Metastable State of Atomically Dispersed Tin in Copper Oxide for Selective CO Electroreduction.

Metastable state is the most active catalyst state that dictates the overall catalytic performance and rules of catalytic behaviors; however, identification and stabilization of the metastable state of catalyst are still highly challenging due to the continuous evolution of catalytic sites during the reaction process. In this work, Sn Mössbauer measurements and theoretical simulations were performed to track and identify the metastable state of single-atom Sn in copper oxide (Sn-CuO) for highly selective CO electroreduction to CO. A maximum CO Faradaic efficiency of around 98% at -0.

Modulating Electronic Structure Engineering of Atomically Dispersed Cobalt Catalyst in Fenton-like Reaction for Efficient Degradation of Organic Pollutants.

Currently, the lack of model catalysts limits the understanding of the catalytic essence. Herein, we report the functional group modification of model single atom catalysts (SACs) with an accurately regulated electronic structure for accelerating the sluggish kinetics of the Fenton-like reaction. The amino-modified cobalt phthalocyanine anchored on graphene (CoPc/G-NH) shows superior catalytic performance in the peroxymonosulfate (PMS) based Fenton-like reaction with Co mass-normalized pseudo-first-order reaction rate constants (, 0.

In-situ spectroscopic probe of the intrinsic structure feature of single-atom center in electrochemical CO/CO reduction to methanol.

While exploring the process of CO/CO electroreduction (CORR) is of great significance to achieve carbon recycling, deciphering reaction mechanisms so as to further design catalytic systems able to overcome sluggish kinetics remains challenging. In this work, a model single-Co-atom catalyst with well-defined coordination structure is developed and employed as a platform to unravel the underlying reaction mechanism of CORR. The as-prepared single-Co-atom catalyst exhibits a maximum methanol Faradaic efficiency as high as 65% at 30 mA/cm in a membrane electrode assembly electrolyzer, while on the contrary, the reduction pathway of CO to methanol is strongly decreased in CORR.

Spectroscopic Analysis of Axial Oxygen-Coordinated Single-Sn-Atom Sites for Electrochemical CO Reduction.

Sn-based materials have been demonstrated as promising catalysts for the selective electrochemical CO reduction reaction (CORR). However, the detailed structures of catalytic intermediates and the key surface species remain to be identified. In this work, a series of single-Sn-atom catalysts with well-defined structures is developed as model systems to explore their electrochemical reactivity toward CORR.

Halogen-Incorporated Sn Catalysts for Selective Electrochemical CO2 Reduction to Formate.

Electrochemically reducing CO to valuable fuels or feedstocks is recognized as a promising strategy to simultaneously tackle the crises of fossil fuel shortage and carbon emission. Sn-based catalysts have been widely studied for electrochemical CO reduction reaction (CO RR) to make formic acid/formate, which unfortunately still suffer from low activity, selectivity and stability. In this work, halogen (F, Cl, Br or I) was introduced into the Sn catalyst by a facile hydrolysis method.

Rational Positioning of Metal Ions to Stabilize Open Tin Sites in Beta Zeolite for Catalytic Conversion of Sugars.

Via hydrothermal synthesis of Sn-Al gels, mild dealumination and ion exchange, a bimetallic Sn-Ni-Beta catalyst was prepared which can convert glucose to methyl lactate (MLA) and methyl vinyl glycolate (MVG) in methanol at yields of 71.2 % and 10.2 %, respectively.

A novel Zn-Al spinel-alumina composite supported gold catalyst for efficient CO oxidation.

A spinel-alumina inert oxide supported gold catalyst with high Au dispersion and excellent CO oxidation activity was developed by a deposition-precipitation method. The activation atmosphere could tune the reaction pathway by adjusting the amount of surface adsorbed water species, thus transforming the reaction intermediates from HCO or CO to COOH.