High-spin surface Fe = O synthesis with molecular oxygen and pyrite for selective methane oxidation.

Nature-inspired high-spin Fe = O generation enables efficient ambient methane oxidation. By engineering sulfur-bridged dual ≡Fe…Fe≡ sites on pyrite (FeS) mimicking soluble methane monooxygenase, we achieve O-driven formation of high-spin (S = 2) surface Fe = O species at room temperature and pressure. Strategic removal of bridging S atoms creates active sites that facilitate O activation via transient ≡Fe-O-O-Fe≡ intermediates, promoting homolytic O - O bond cleavage.

Surface Fe═O Induced Highly Selective Phenol Polymerization via Proton-Coupled Electron Transfer.

Organic polymerization offers a sustainable alternative for water decontamination and resource recovery; however, its popularization is bottlenecked by the unsatisfactory selectivity of traditional electron transfer processes. In this study, we demonstrate that surface high-valent iron-oxo species (≡Fe═O) on nanoscale zerovalent iron (nZVI), characterized by an unoccupied d orbital and a terminal-oxo moiety, can realize highly efficient phenol recovery via a proton-coupled electron transfer (PCET) pathway for phenol transformation into phenoxyl radicals with final polymers of 3231 g mol in average molecular weight and an impressive polymeric selectivity of 92.6%, surpassing those reported in free radical-/catalyst-oxidant complex-based systems driven by electron transfer (below 77.

Homolytic HO Dissociation into Hydroxyl and Hydrogen Radicals on Sulfur-Deficient Greigite for Efficient Hydration Reactions.

Homolytic dissociation of ubiquitous water (HO) into radical species is pivotal in driving reactions across chemical, biological, geoscientific, and environmental domains; yet, it faces substantial challenges in cleaving the robust O-H bond and preventing radical recombination. Herein, we demonstrate that greigite with sulfur vacancies (SVs) can ambiently dissociate HO into reactive hydroxyl (•OH) and hydrogen (•H) radicals in a stoichiometric manner. This process is facilitated by the inverse-spinel structure of FeS, where the antiparallel arrangement of high-spin Fe atoms localizes electrons at SVs, enabling barrierless cleavage of the O-H bond to yield •OH and •H.

Planar asymmetric surface Fe = O synthesis with pyrite and chlorite for efficient oxygen atom transfer reactions.

Surface high-valent iron-oxo species (≡Fe=O) are reliable and green oxygen atom transfer reagents, but the ability is seriously inhibited by the maximal orbital overlap of axial Fe = O double bond in a symmetric planar coordination environment. Herein, we report the synthesis of planar asymmetric surface Fe = O (PA-≡Fe = O) on pyrite using chlorite as the oxidant, where the in-situ generated ClO can transform a planar Fe-S bond to Fe-Cl by oxidizing and subsequently substituting planar sulfur atoms. Different from planar symmetric surface Fe = O (PS-≡Fe = O) with electron localization around axial Fe = O, PA-≡Fe = O delocalizes electrons among Fe, axial oxo moiety and its planar ligands owing to the stronger electron-withdrawing capacity of Cl, which effectively weakens the orbital overlap of axial Fe = O bonding and thus facilitates the rapid electron transfer from the substrates to the unoccupied antibonding orbital of PA-≡Fe = O, realizing more efficient oxygen atom transfer oxidation of methane, methyl phenyl sulfide, triphenylphosphonate and styrene than PS-≡Fe = O.

Low-Coordinated Polysulfide Species on Metal Sulfide Enabled Superior Gaseous Mercury Removal from Natural Gas.

The pursuit of efficient natural gas utilization is inherently linked to thorough purification of its contaminants. Traditional purification techniques, while adept at removing sulfur-containing acid gases (e.g.

Single Mn atom modulated molecular oxygen activation over TiO for photocatalytic formaldehyde oxidation.

In single-atom catalysts, the atomically dispersed metal sites are pivotal for oxygen molecule activation. We hypothesize that dispersing single Mn atoms on TiO nanosheets may improve the photocatalytic oxidation of formaldehyde (HCHO) in the gas phase under ambient conditions. Density function theory (DFT) and experimental experiments were carried out to single Mn atoms not only improved the transfer of localized electrons and photogenerated electrons but also enhanced the activation/dissociation of O to generate monoatomic oxygen ions (O) as the final reactive oxygen species (ROS).

Highly selective synthesis of surface Fe=O with nanoscale zero-valent iron and chlorite for efficient oxygen transfer reactions.

High-valent iron-oxo species (Fe=O) has been a long-sought-after oxygen transfer reagent in biological and catalytic chemistry but suffers from a giant challenge in its gentle and selective synthesis. Herein, we propose a new strategy to synthesize surface Fe=O (≡Fe=O) on nanoscale zero-valent iron (nZVI) using chlorite (ClO) as the oxidant, which possesses an impressive ≡Fe=O selectivity of 99%. ≡Fe=O can be energetically formed from the ferrous (Fe) sites on nZVI through heterolytic Cl-O bond dissociation of ClO via a synergistic effect between electron-donating surface ≡Fe and proximal electron-withdrawing HO, where HO serves as a hydrogen-bond donor to the terminal O atom of the adsorbed ClO thereby prompting the polarization and cleavage of Cl-O bond for the oxidation of ≡Fe toward the final formation of ≡Fe=O.

Oxalated zero valent iron enables highly efficient heterogeneous Fenton reaction by self-adapting pH and accelerating proton cycle.

Heterogeneous Fenton reactions of zero-valent iron (ZVI) requires the sufficient release of Fe(II) to catalyze the HO decomposition. However, the rate-limiting step of proton transfer through the passivation layer of ZVI restricted the Fe(II) release via Fe core corrosion. Herein we modified the shell of ZVI with highly proton-conductive FeCO·2HO by ball-milling (OA-ZVI), and demonstrated its high heterogeneous Fenton performance of thiamphenicol (TAP) removal, with 500 times enhancement of the rate constant.

Pyrolysis temperature-switchable Fe-N sites in pharmaceutical sludge biochar toward peroxymonosulfate activation for efficient pollutants degradation.

Pyrolysis of pharmaceutical sludge (PS) is a promising way of safe disposal and to recover energy and resources from waste. The resulting PS biochar (PSBC) is often used as adsorbent, but has seldom been explored as catalyst. Herein we demonstrate that PSBC (0.

Electrochemical removal of ammonium nitrogen in high efficiency and N selectivity using non-noble single-atomic iron catalyst.

Ammonia nitrogen (NH-N) is a ubiquitous environmental pollutant, especially in offshore aquaculture systems. Electrochemical oxidation is very promising to remove NH-N, but suffers from the use of precious metals anodes. In this work, a robust and cheap electrocatalyst, iron single-atoms distributed in nitrogen-doped carbon (Fe-SAs/N-C), was developed for electrochemical removal of NH-N from in wastewater containing chloride.

An Electrochemical Strategy for Simultaneous Heavy Metal Complexes Wastewater Treatment and Resource Recovery.

Heavy metals chelated with coexisting organic ligands in wastewater impose severe risks to public health and the ambient ecosystem but are also valuable metal resources. For sustainable development goals, the treatment of heavy metal complexes wastewater requires simultaneous metal-organic bond destruction and metal resource recovery. In this study, we demonstrated that a neutral pH electro-Fenton (EF) system, which was composed of an iron anode, carbon cloth cathode, and sodium tetrapolyphosphate electrolyte (NaTPP), could induce a successive single-electron activation pathway of molecular oxygen due to the formation of Fe(II)-TPP complexes.

A controllable reduction-oxidation coupling process for chloronitrobenzenes remediation: From lab to field trial.

Chloronitrobenzenes (CNBs) are typical refractory aromatic pollutants. The reduction products of CNBs often possess higher toxicity, and the electron-withdrawing substituent groups are detrimental to the ring-opening during the oxidation treatment, leading to ineffective removal of CNBs by either reduction or oxidation technology. Herein we demonstrate a controllable reduction-oxidation coupling (ROC) process composed of zero-valent iron (ZVI) and HO for the effective removal of CNBs from both water and soil.

Atomic-Layered Cu Nanoclusters on FeS with Dual Catalytic Sites for Efficient and Selective H O Activation.

Regulating the distribution of reactive oxygen species generated from H O activation is the prerequisite to ensuring the efficient and safe use of H O in the chemistry and life science fields. Herein, we demonstrate that constructing a dual Cu-Fe site through the self-assembly of single-atomic-layered Cu nanoclusters onto a FeS surface achieves selective H O activation with high efficiency. Unlike its unitary Cu or Fe counterpart, the dual Cu-Fe sites residing at the perimeter zone of the Cu /FeS interface facilitate H O adsorption and barrierless decomposition into ⋅OH via forming a bridging Cu-O-O-Fe complex.

Adjacent single-atom irons boosting molecular oxygen activation on MnO.

Efficient molecular oxygen activation is crucial for catalytic oxidation reaction, but highly depends on the construction of active sites. In this study, we demonstrate that dual adjacent Fe atoms anchored on MnO can assemble into a diatomic site, also called as MnO-hosted Fe dimer, which activates molecular oxygen to form an active intermediate species Fe(O = O)Fe for highly efficient CO oxidation. These adjacent single-atom Fe sites exhibit a stronger O activation performance than the conventional surface oxygen vacancy activation sites.

Simultaneous Manipulation of Bulk Excitons and Surface Defects for Ultrastable and Highly Selective CO Photoreduction.

The objective of photocatalytic CO reduction (PCR) is to achieve high selectivity for a single energy-bearing product with high efficiency and stability. The bulk configuration usually determines charge carrier kinetics, whereas surface atomic arrangement defines the PCR thermodynamic pathway. Concurrent engineering of bulk and surface structures is therefore crucial for achieving the goal of PCR.

Kirkendall Effect Boosts Phosphorylated nZVI for Efficient Heavy Metal Wastewater Treatment.

Removal of non-biodegradable heavy metals has been the top priority in wastewater treatment and the development of green technologies remains a significant challenge. We demonstrate that phosphorylated nanoscale zero-valent iron (nZVI) is promising for removal of heavy metals (Ni , Cu , Cr , Hg ) via a boosted Kirkendall effect. Phosphorylation confines tensile hoop stress on the nZVI particles and "breaks" the structurally dense spherical nZVI to produce numerous radial nanocracks.

One-pot synthesis of Schiff base compounds via photocatalytic reaction in the coupled system of aromatic alcohols and nitrobenzene using CdInS photocatalyst.

The use of solar energy to drive organic reactions under mild conditions provides a sustainable pathway for green synthesis and has been one of the primary goals pursued by scientists. In this research, the cadmium indium sulfide (CdIn2S4) photocatalyst was prepared using a simple solvothermal method and was thoroughly characterized using X-ray powder diffraction, UV-visible absorption spectra, nitrogen adsorption-desorption isotherms, scanning electron microscopy, transmission electron microscopy and X-ray spectroscopy measurements. The photocatalytic performance of the CdIn2S4 photocatalyst was evaluated using photocatalytic synthesis of Schiff base compounds in a coupled system of aromatic alcohols and nitrobenzene under visible light irradiation.

Solvothermal synthesis of CdInS photocatalyst for selective photosynthesis of organic aromatic compounds under visible light.

Ternary chalcogenide semiconductor, cadmium indium sulfide (CdInS), was prepared by a simple solvothermal method using ethylene glycol as a solvent, as well as indium chloride tetrahydrate (InCl4HO), cadmium nitrate tetrahydrate [Cd(NO)4HO], and thiacetamide (TAA) as precursors. The resulted sample was subject to a series of characterizations. It is the first time to use CdInS sample as a visible light-driven photocatalyst for simultaneous selective redox transformation of organic aromatic compounds.