Double coordination shell modulation of nitrogen-free atomic manganese sites for enhancing oxygen reduction performance.

The rational design and fabrication of the active sites of single-atom catalysts (SACs) remains the main breakthrough for efficient electrocatalytic oxygen reduction reaction (ORR). Although metal-nitrogen-carbon (M-N-C) materials have been reported to exhibit good ORR performance, the M-N bond is prone to oxidation and subsequent destruction in Fenton-like reactions. Here, we report a nitrogen-free Mn-based SAC (Mn-SOG-600) anchored on a nitrogen-free graphene substrate, where manganese is bound to four oxygen atoms and one sulfur atom across two different coordination shells.

Modifying d-p orbital hybridization of Ni/FeO species by high-valence ruthenium doping to enhance oxygen evolution performance.

The electron distribution of catalysts can be modulated by high-valence metal doping, thus enhancing the intrinsic activity. Herein, we adopt Ru modification to adjust the d-p orbital hybridization of Ni-Fe oxyhydroxides, significantly increasing the oxygen evolution reaction (OER) activity. The amorphous NiFeRuOH catalyst synthesized by sol-gel method exhibits excellent OER activity, far superior to commercial RuO.

Structure-Activity Relationships in Oxygen Electrocatalysis.

Oxygen electrocatalysis, as the pivotal circle of many green energy technologies, sets off a worldwide research boom in full swing, while its large kinetic obstacles require remarkable catalysts to break through. Here, based on summarizing reaction mechanisms and in situ characterizations, the structure-activity relationships of oxygen electrocatalysts are emphatically overviewed, including the influence of geometric morphology and chemical structures on the electrocatalytic performances. Subsequently, experimental/theoretical research is combined with device applications to comprehensively summarize the cutting-edge oxygen electrocatalysts according to various material categories.

Spin effect in dual-atom catalysts for electrocatalysis.

The development of high-efficiency atomic-level catalysts for energy-conversion and -storage technologies is crucial to address energy shortages. The spin states of diatomic catalysts (DACs) are closely tied to their catalytic activity. Adjusting the spin states of DACs' active centers can directly modify the occupancy of d-orbitals, thereby influencing the bonding strength between metal sites and intermediates as well as the energy transfer during electro reactions.

Single-atom nanozymes for antibacterial applications.

Bacteria have always been a thorny problem that threatens human health and food safety. Conventional antibiotic treatment often leads to the emergence of drug resistance. Therefore, the development of more effective antibacterial agents is urgently needed.

Advances and challenges in the electrochemical reduction of carbon dioxide.

The electrocatalytic carbon dioxide reduction reaction (ECORR) is a promising way to realize the transformation of waste into valuable material, which can not only meet the environmental goal of reducing carbon emissions, but also obtain clean energy and valuable industrial products simultaneously. Herein, we first introduce the complex CORR mechanisms based on the number of carbons in the product. Since the coupling of C-C bonds is unanimously recognized as the key mechanism step in the ECORR for the generation of high-value products, the structural-activity relationship of electrocatalysts is systematically reviewed.

Nanoflower-Like High-Entropy Co-Fe-Cr-Mo-Mn Spinel for Oxygen Evolution.

Oxygen evolution reaction (OER) is the key anode reaction of electrolytic water. To improve the slow OER kinetics, we synthesize nanoflower-like Co-Fe-Cr-Mo-Mn high-entropy spinel (HES) nanosheets on nickel foam (NF) by one-step solvothermal method, which exhibit an overpotential (η) of only 188 mV at 10 mA cm, much lower than bimetallic CoFeO/NF (233 mV), trimetallic CoFeCrO/NF (211 mV), and tetrametallic CoFeCrMoO/NF (200 mV). The OER overpotential decreases with the increase of the number of metals, indicating that the formation of HES has a positive effect on the improvement of electrocatalytic performance, since the synergistic effect between different metals enhances the charge transfer rate and decreases reaction barrier.

Optimization strategies of high-entropy alloys for electrocatalytic applications.

High-entropy alloys (HEAs) are expected to become one of the most promising functional materials in the field of electrocatalysis due to their site-occupancy disorder and lattice order. The chemical complexity and component tunability make it possible for them to obtain a nearly continuous distribution of adsorption energy curve, which means that the optimal adsorption strength and maximum activity can be obtained by a multi-alloying strategy. In the last decade, a great deal of research has been performed on the synthesis, element selection and catalytic applications of HEAs.

Achievements and challenges of copper-based single-atom catalysts for the reduction of carbon dioxide to C2+ products.

Copper is the only metal that can convert CO into C2 and C2+ in electrocatalytic carbon dioxide reduction (CORR). However, the Faraday efficiency of CO conversion to C2 and C2+ products at high current densities is still low, which cannot meet the actual industrial demand. Here, the design methods of single-atom copper catalysts (including regulating the coordination environment of single-atom copper, modifying the carbon base surface and constructing diatomic Cu catalysts) are reviewed, and the current limitations and future research directions of copper-based single-atom catalysts are proposed, providing directions for the industrial conversion of CO into C2 and C2+ products.

synthesis of rosette-like Co-doped FeNiOOH/NF for seawater oxidation.

The development of high activity and strong resistance to seawater corrosion oxygen evolution reaction (OER) electrocatalysts for seawater electrolysis has broad application prospects. Herein, we prepare Co-doped FeNiOOH rosette-like nanoflowers on nickel foam (NF) with different Co dosages by one-step solvothermal method. The Co-FeNiOOH/NF exhibits a low overpotential () of 185 mV and Tafel slope of 30 mV dec in 1 M KOH.

Nanoflower-like high-entropy Ni-Fe-Cr-Mn-Co (oxy)hydroxides for oxygen evolution.

High-entropy materials (HEMs) have potential application value in electrocatalytic water splitting because of their unique alloy design concept and significant mixed entropy effect. Here, we synthesize a high-entropy Ni-Fe-Cr-Mn-Co (oxy)hydroxide on nickel foam (NF) by a solvothermal method. The flower-like structure of FeNiCrMnCoOOH/NF can provide abundant active sites, thus improving the oxygen evolution reaction (OER) activity.

Electron coupling effect-triggered monatomic copper laccase-mimicking nanozyme for the degradation and detection of guaiacol produced by Alicyclobacillus acidoterrestris.

The generation of guaiacol by Alicyclobacillus acidoterrestris (A. acidoterrestris) in fruit juices negatively affects public health and causes severe environmental pollution. Therefore, the sensitive detection and efficient degradation of guaiacol in real samples are crucial.

Single-atom nanozyme-based electrochemical sensors for health and food safety monitoring.

Electrochemical sensors and biosensors play an important role in many fields, including biology, clinical trials, and food industry. For health and food safety monitoring, accurate and quantitative sensing is needed to ensure that there is no significantly negative impact on human health. It is difficult for traditional sensors to meet these requirements.

Nanozyme colorimetric sensor array based on monatomic cobalt for the discrimination of sulfur-containing metal salts.

The identification of sulfur-containing metal salts (SCMs) is of great interest because they play an important role in many biological processes and diseases. Here, we constructed a ternary channel colorimetric sensor array to detect multiple SCMs simultaneously, relying on monatomic Co embedded in nitrogen-doped graphene nanozyme (CoN-G). Due to the unique structure, CoN-G exhibits activity similar to native oxidases, capable of catalysing directly the oxidization of 3,3',5,5'-tetramethylbenzidine (TMB) by O molecules independent of HO.

Effect of Metal Complexing on Mn-Fe/TS-1 Catalysts for Selective Catalytic Reduction of NO with NH.

TS-1 zeolite with desirable pore structure, an abundance of acidic sites, and good thermal stability promising as a support for the selective catalytic reduction of NO with NH (NH-SCR). Herein, a series of Mn-Fe/TS-1 catalysts have been synthesized, adopting tetraethylenepentamine (TEPA) as a metal complexing agent using the one-pot hydrothermal method. The introduced TEPA can not only increase the loading of active components but also prompts the formation of a hierarchical structure through decreasing the size of TS-1 nanocrystals to produce intercrystalline mesopores during the hydrothermal crystallization process.

Electrocatalysts for Oxygen/Hydrogen-Involved Reactions.

Oxygen/hydrogen-involved reactions are key reactions in many energy-related technologies, such as electrolytic water, electrocatalytic carbon dioxide reduction, electrochemical ammonia synthesis, rechargeable metal-air batteries, and renewable fuel cells [...

A binuclear Co-based metal-organic framework towards efficient oxygen evolution reaction.

The search for low-cost and high-performance electrocatalysts for oxygen evolution reaction (OER) has aroused enormous research interest in the last few years. Reported herein is the topotactic construction of a binuclear Co-based metal-organic framework (Co2-tzpa) using a solvothermal reaction. Prominently, as a porous catalyst, Co2-tzpa holds its activity for at least 25 hours and exhibits low OER overpotentials of 336 and 396 mV to achieve the current density of 10 mA cm-2 in 1 M KOH and 0.

Promotion of the water oxidation activity of iridium oxide by a nitrogen coordination strategy.

The water oxidation reaction is the pivotal half-reaction for photo-/electro-catalytic water splitting. Fabrication of high-efficiency and robust water oxidation is essential to realize wide-scale artificial photosynthesis. Here, we report an efficient strategy to improve the water oxidation activity of iridium oxide by a nitrogen-coordination method.

Enhancing Methane Aromatization Performance by Reducing the Particle Size of Molybdenum Oxide.

Efficient use of natural gas to produce aromatics is an attractive subject; the process requires catalysts that possess high-performance active sites to activate stable C-H bonds. Here, we report a facile synthetic strategy to modify HMCM-49 with small molybdenum oxide nanoparticles. Due to the higher sublimability of nano-MoO particles than commercial MoO, they more easily enter into the channels of HMCM-49 and associate with Brønsted acid sites to form active MoC-type species under calcination and reaction conditions.

Recent advancement in the electrocatalytic synthesis of ammonia.

Ammonia can not only be used as an active nitrogen component of nitrogen fertilizers, fibers, explosives, etc., but also provides a high energy density and carbon free energy carrier. Currently, ammonia is industrially synthesized by the Haber Bosch process at high temperature and high pressure, which results in high energy loss and a serious greenhouse effect.

Atomic cobalt catalysts for the oxygen evolution reaction.

Development of high-efficiency single-atom catalysts (SACs) for the oxygen evolution reaction (OER) is challenging. Herein, we report a facile annealing strategy to construct an atomically dispersed cobalt- and nitrogen-codoped graphene catalyst for high-efficiency OER. The as-prepared 0.

Mono-/Multinuclear Water Oxidation Catalysts.

Water splitting, in which water molecules can be transformed into hydrogen and oxygen, is an appealing energy conversion and transformation strategy to address the environmental and energy crisis. The oxygen evolution reaction (OER) is dynamically slow, which limits energy conversion efficiency during the water-splitting process and requires high-efficiency water oxidation catalysts (WOCs) to overcome the OER energy barrier. It is generally accepted that multinuclear WOCs possess superior OER performances, as demonstrated by the CaMn O cluster in photosystem II (PSII), which can catalyze the OER efficiently with a very low overpotential.