The catalyst's structural dynamics under reaction conditions critically determine their performance.We proved this indication by studying Ni nanoparticles supported on Mo_(2)CT_(x) MXene,where the average size dur...The catalyst's structural dynamics under reaction conditions critically determine their performance.We proved this indication by studying Ni nanoparticles supported on Mo_(2)CT_(x) MXene,where the average size during CO_(2) hydrogenation changed from 12.9 to 3.1 nm.A parallel increase of CO selectivity from 21.1%to 92.6%at 400℃ was observed,while the CO_(2) conversion rate remained at about 84.0 mmol·g_(cat)^(-1)·h^(-1).This transformation involved partial removal of Mo_(2)CT_(x) terminal groups,allowing direct interaction between Ni and Mo atoms instead of indirect coupling through-O terminations.The shift from a Ni-O-Mo to a Ni-Mo interaction enhanced electron transfer from Ni to Mo_(2)CT_(x),strengthening the metal-support interaction and driving Ni nanoparticle dispersion.In-situ mechanistic analysis and kinetic isotope studies revealed that Ni dispersion suppresses the formate and carboxyl pathway,promotes direct CO_(2) dissociation,and inhibits CO hydrogenation,shifting the primary product from CH_(4) to CO.These findings provide a strategy for designing highly selective and stable MXene-based catalysts through engineered metal-support interactions.展开更多
Converting CO_(2)to CO through the thermocatalytic reverse water gas shift(RWGS)is an industrially relevant reaction for carbon circularity.Improvements in catalyst design for this reaction are highly required,not onl...Converting CO_(2)to CO through the thermocatalytic reverse water gas shift(RWGS)is an industrially relevant reaction for carbon circularity.Improvements in catalyst design for this reaction are highly required,not only in terms of active metal sites but also as novel possibilities for oxide support involvement in the reactant activation and surface transportation of the intermediate species.Here,we present the concept of engineering dual-active sites on CeO_(x)-modified defective MgO to enhance CO_(2)adsorption and H species spillover.Compared to bulk oxide-supported catalysts,the Pt/Ce_(4.1)-MgO catalyst with abundant MgO-defects enhanced by cerium-modification exhibits a significantly high CO_(2)conversion(56.1%,near to equilibrium conversion)and a CO formation rate of up to 491μmol g_(cat.)^(-1)h^(-1)with a selectivity to carbon monoxide exceeding 97%at 600℃.This high-performance dual-site catalyst was studied in detail using many techniques,including H_(2)/D_(2)kinetic isotope effects,temperature programmed and kinetic experiments,and CO_(2)adsorption isotherms.The data prove that the highly dispersed Ce,in the form of single atoms or small surface nano patches,enhances the formation of coordinatively unsaturated sites,which favour CO_(2)absorption and reduction in the presence of H spillover migrating from Pt nanoparticles.This novel design leads to improved CO_(2)reduction to CO.In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)experiments show that the enhanced carbonate and formate species contributed to the improved RWGS performance over the Pt/Ce_(4.1)-MgO catalyst.These results pave the way for designing efficient CO_(2)hydrogenation catalysts by the creation of the unsaturated oxide-oxide interface on the support.展开更多
After short introducing the crucial role of e‐fuels to meet net‐zero emissions targets,this perspective paper discusses the differences between reactive catalysis(electro‐,photo‐and plasma‐catalysis,with focus on...After short introducing the crucial role of e‐fuels to meet net‐zero emissions targets,this perspective paper discusses the differences between reactive catalysis(electro‐,photo‐and plasma‐catalysis,with focus on the first for conciseness)and thermal catalysis used at most.The main point is to evidence that to progress in producing e‐fuels,the gap is not in terms of scaling‐up and pilot testing,but rather in the fundamental needs to turn the current approach and methodologies to develop reactive catalysis,including from a mechanistic perspective,to go beyond the current methods largely derived from thermal catalysis.Developing thus new fundamental bases to understand reactive catalysis is the challenge to accelerate the progress in this area to enable the potential role towards a sustainable net‐zero emissions future.Some novel aspects are highlighted,but the general aim is rather to stimulate discussion in rethinking catalysis from an alternative perspective.展开更多
The role of NH4^+ ion confinement in the catalytic etherification of HMF(5-hydroxymethylfurfural) with ethanol to biodiesel additives was evidenced by studying the catalytic behavior of NH4^+-Beta zeolites with SiO2/A...The role of NH4^+ ion confinement in the catalytic etherification of HMF(5-hydroxymethylfurfural) with ethanol to biodiesel additives was evidenced by studying the catalytic behavior of NH4^+-Beta zeolites with SiO2/Al2O3 ratios of 25 and 75.In order to affect the strength and distribution of the acidic sites, as well as the mobility of NH4^+ ions in the zeolites cages, a secondary level of porosity was introduced in the NH4^+-Beta, presenting a different stability versus alkaline treatment, by using a thermal or an ultrasound assisted method.By analyzing the catalytic behavior in these two series of samples with respect to the changes in porosity by nonlocal density functional theory, structure by XRD, amount of acid sites by FT-IR and mobility of NH4^+ cations by measurements of reversible NH4^+ exchange capacity, was evidenced a decrease in catalytic performances both in terms of rate of HMF depletion and productivity to the main products, when confinement of the ammonium ions is lost due to the introduction of mesoporosity.The high capability of ammonium ions release, associated to the mono-dentate configuration,and the minor confinement effect inside the zeolite pore system, due to the more opened pores structure of mesoporous zeolites, hinders both the direct etherification of HMF to EMF [5-(ethoxymethyl)furan-2-carbaldehyde] and the parallel reaction pathway via acetalization, favoring the rapid desorption of the HMFDEA [5-(hydroxymethyl)furfural diethyl acetal] product out of the crystal and the consequent inhibition of the consecutive reactions to EMFDEA [5-(ethoxymethyl)furfural diethyl acetal] and EMF.展开更多
Electrodes prepared by anodic oxidation of Ti foils are robust and not toxic materials for the electrocatalytic reduction of oxalic acid to glycolic acid, allowing the development of a renewable energy-driven process ...Electrodes prepared by anodic oxidation of Ti foils are robust and not toxic materials for the electrocatalytic reduction of oxalic acid to glycolic acid, allowing the development of a renewable energy-driven process for producing an alcoholic compound from an organic acid at low potential and room temperature. Coupled with the electrochemical synthesis of the oxalic acid from CO_(2),this process represents a new green and low-carbon path to produce added value chemicals from CO_(2). Various electrodes prepared by anodic oxidation of Ti foils were investigated. They were characterized by the presence of a TiO_(2) nanotube array together with the presence of small patches, debris, or TiO_(2) nanoparticles. The concentration of oxygen vacancies, the amount of Ti^(3+) measured by X-ray photoelectron spectroscopy(XPS) and the intensity of the anodic peak measured by cyclic voltammetry, were positively correlated with the achieved oxalic acid conversion and glycolic acid yield. The analysis of the results indicates the presence of small amorphous TiO_(2) nanoparticles(or surface patches or debris) interacting with TiO_(2) nanotubes, the sites responsible for the conversion of oxalic acid and glycolic acid yield. By varying this structural characteristic of the electrodes, it is possible to tune the glycolic acid to glyoxylic acid relative ratio. A best cumulative Faradaic efficiency(FE) of about 84% with FE to glycolic acid around 60% and oxalic conversion about 30% was observed.展开更多
Water is a fascinating material.Its composition is simple—one oxygen and two hydrogen atoms—but its chemistry and physics are extremely complex and exhibit 75 documented anomalies.Although these anomalies and their ...Water is a fascinating material.Its composition is simple—one oxygen and two hydrogen atoms—but its chemistry and physics are extremely complex and exhibit 75 documented anomalies.Although these anomalies and their molecular origin are not completely understood,we know that hydrogen bonds play key roles in all of the phases of water.Moreover,there is experimental evidence that the polymorphism of the ice structure extends into the liquid phase and is associated with a liquid-liquid coexistence line.This is currently a topic of great interest in water research because there are indications that the end point of the coexistence line corresponds to a second critical point inside the supercooled liquid regime.We examine the recent progress in understanding water anomalies and the liquid-liquid phase transition hypothesis,including the results of recent experimental work and molecular simulations of both bulk and confined water.We examine experimental results that test whether the behavior of liquid water is consistent with the"liquid polymorphism"hypothesis that liquid water can exist in two distinct phases of differing densities.We also examine recent research on the anomalies of nanoconfined water and,in particular,on water in biological environments.We find that the concept of liquid polymorphism can also describe the properties of other liquids that have two characteristic length scales.展开更多
文摘The catalyst's structural dynamics under reaction conditions critically determine their performance.We proved this indication by studying Ni nanoparticles supported on Mo_(2)CT_(x) MXene,where the average size during CO_(2) hydrogenation changed from 12.9 to 3.1 nm.A parallel increase of CO selectivity from 21.1%to 92.6%at 400℃ was observed,while the CO_(2) conversion rate remained at about 84.0 mmol·g_(cat)^(-1)·h^(-1).This transformation involved partial removal of Mo_(2)CT_(x) terminal groups,allowing direct interaction between Ni and Mo atoms instead of indirect coupling through-O terminations.The shift from a Ni-O-Mo to a Ni-Mo interaction enhanced electron transfer from Ni to Mo_(2)CT_(x),strengthening the metal-support interaction and driving Ni nanoparticle dispersion.In-situ mechanistic analysis and kinetic isotope studies revealed that Ni dispersion suppresses the formate and carboxyl pathway,promotes direct CO_(2) dissociation,and inhibits CO hydrogenation,shifting the primary product from CH_(4) to CO.These findings provide a strategy for designing highly selective and stable MXene-based catalysts through engineered metal-support interactions.
基金financially supported by the National Key Research and Development Program of China(2024YFB4006600)the NSFC of China(22472168 and 22172161)+4 种基金the Natural Science Foundation of Liaoning Province(2024-MSBA-57)the Dalian Institute of Chemical Physics(DICP I202421)the Energy Revolution S&T Program of Yulin Innovation Institute of Clean Energy(E411030705)the support from the CAS President’s International Fellowship Initiative(PIFI)programthe SCOPE ERC Synergy project(ID 810182)。
文摘Converting CO_(2)to CO through the thermocatalytic reverse water gas shift(RWGS)is an industrially relevant reaction for carbon circularity.Improvements in catalyst design for this reaction are highly required,not only in terms of active metal sites but also as novel possibilities for oxide support involvement in the reactant activation and surface transportation of the intermediate species.Here,we present the concept of engineering dual-active sites on CeO_(x)-modified defective MgO to enhance CO_(2)adsorption and H species spillover.Compared to bulk oxide-supported catalysts,the Pt/Ce_(4.1)-MgO catalyst with abundant MgO-defects enhanced by cerium-modification exhibits a significantly high CO_(2)conversion(56.1%,near to equilibrium conversion)and a CO formation rate of up to 491μmol g_(cat.)^(-1)h^(-1)with a selectivity to carbon monoxide exceeding 97%at 600℃.This high-performance dual-site catalyst was studied in detail using many techniques,including H_(2)/D_(2)kinetic isotope effects,temperature programmed and kinetic experiments,and CO_(2)adsorption isotherms.The data prove that the highly dispersed Ce,in the form of single atoms or small surface nano patches,enhances the formation of coordinatively unsaturated sites,which favour CO_(2)absorption and reduction in the presence of H spillover migrating from Pt nanoparticles.This novel design leads to improved CO_(2)reduction to CO.In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)experiments show that the enhanced carbonate and formate species contributed to the improved RWGS performance over the Pt/Ce_(4.1)-MgO catalyst.These results pave the way for designing efficient CO_(2)hydrogenation catalysts by the creation of the unsaturated oxide-oxide interface on the support.
基金supported by EU with ERC Synergy SCOPE(Surface-Confined Fast-modulated Plasma for Process and Energy Intensification in Small Molecules Conversion,810182)ProjectItalian MUR by PRIN 2017 Projects MULTI-e (Multielectron Transfer for the Conversion of Small Moleculesan Enabling Technology for the Chemical Use of Renewable Energy,20179337R7)CO_(2) ONLY (CO_(2) as Only Source of Carbons for Monomers and PolymersA Step Forwards Circular economy) Project,017WR2LRS
文摘After short introducing the crucial role of e‐fuels to meet net‐zero emissions targets,this perspective paper discusses the differences between reactive catalysis(electro‐,photo‐and plasma‐catalysis,with focus on the first for conciseness)and thermal catalysis used at most.The main point is to evidence that to progress in producing e‐fuels,the gap is not in terms of scaling‐up and pilot testing,but rather in the fundamental needs to turn the current approach and methodologies to develop reactive catalysis,including from a mechanistic perspective,to go beyond the current methods largely derived from thermal catalysis.Developing thus new fundamental bases to understand reactive catalysis is the challenge to accelerate the progress in this area to enable the potential role towards a sustainable net‐zero emissions future.Some novel aspects are highlighted,but the general aim is rather to stimulate discussion in rethinking catalysis from an alternative perspective.
文摘The role of NH4^+ ion confinement in the catalytic etherification of HMF(5-hydroxymethylfurfural) with ethanol to biodiesel additives was evidenced by studying the catalytic behavior of NH4^+-Beta zeolites with SiO2/Al2O3 ratios of 25 and 75.In order to affect the strength and distribution of the acidic sites, as well as the mobility of NH4^+ ions in the zeolites cages, a secondary level of porosity was introduced in the NH4^+-Beta, presenting a different stability versus alkaline treatment, by using a thermal or an ultrasound assisted method.By analyzing the catalytic behavior in these two series of samples with respect to the changes in porosity by nonlocal density functional theory, structure by XRD, amount of acid sites by FT-IR and mobility of NH4^+ cations by measurements of reversible NH4^+ exchange capacity, was evidenced a decrease in catalytic performances both in terms of rate of HMF depletion and productivity to the main products, when confinement of the ammonium ions is lost due to the introduction of mesoporosity.The high capability of ammonium ions release, associated to the mono-dentate configuration,and the minor confinement effect inside the zeolite pore system, due to the more opened pores structure of mesoporous zeolites, hinders both the direct etherification of HMF to EMF [5-(ethoxymethyl)furan-2-carbaldehyde] and the parallel reaction pathway via acetalization, favoring the rapid desorption of the HMFDEA [5-(hydroxymethyl)furfural diethyl acetal] product out of the crystal and the consequent inhibition of the consecutive reactions to EMFDEA [5-(ethoxymethyl)furfural diethyl acetal] and EMF.
基金funding from the European Union’s Horizon 2020 research and innovation program under grant agreement ID 767798 (OCEAN)MIUR PRIN 2017 project CO_(2) ONLY project nr. 2017WR2LRS。
文摘Electrodes prepared by anodic oxidation of Ti foils are robust and not toxic materials for the electrocatalytic reduction of oxalic acid to glycolic acid, allowing the development of a renewable energy-driven process for producing an alcoholic compound from an organic acid at low potential and room temperature. Coupled with the electrochemical synthesis of the oxalic acid from CO_(2),this process represents a new green and low-carbon path to produce added value chemicals from CO_(2). Various electrodes prepared by anodic oxidation of Ti foils were investigated. They were characterized by the presence of a TiO_(2) nanotube array together with the presence of small patches, debris, or TiO_(2) nanoparticles. The concentration of oxygen vacancies, the amount of Ti^(3+) measured by X-ray photoelectron spectroscopy(XPS) and the intensity of the anodic peak measured by cyclic voltammetry, were positively correlated with the achieved oxalic acid conversion and glycolic acid yield. The analysis of the results indicates the presence of small amorphous TiO_(2) nanoparticles(or surface patches or debris) interacting with TiO_(2) nanotubes, the sites responsible for the conversion of oxalic acid and glycolic acid yield. By varying this structural characteristic of the electrodes, it is possible to tune the glycolic acid to glyoxylic acid relative ratio. A best cumulative Faradaic efficiency(FE) of about 84% with FE to glycolic acid around 60% and oxalic conversion about 30% was observed.
文摘Water is a fascinating material.Its composition is simple—one oxygen and two hydrogen atoms—but its chemistry and physics are extremely complex and exhibit 75 documented anomalies.Although these anomalies and their molecular origin are not completely understood,we know that hydrogen bonds play key roles in all of the phases of water.Moreover,there is experimental evidence that the polymorphism of the ice structure extends into the liquid phase and is associated with a liquid-liquid coexistence line.This is currently a topic of great interest in water research because there are indications that the end point of the coexistence line corresponds to a second critical point inside the supercooled liquid regime.We examine the recent progress in understanding water anomalies and the liquid-liquid phase transition hypothesis,including the results of recent experimental work and molecular simulations of both bulk and confined water.We examine experimental results that test whether the behavior of liquid water is consistent with the"liquid polymorphism"hypothesis that liquid water can exist in two distinct phases of differing densities.We also examine recent research on the anomalies of nanoconfined water and,in particular,on water in biological environments.We find that the concept of liquid polymorphism can also describe the properties of other liquids that have two characteristic length scales.
