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P-Fe 2 O 3 -CoP nanosheets show high overall freshwater/seawater splitting activity with 1.61/1.65 V at 10 mA/cm2. [Display omitted] • P-Fe 2 O 3 -CoP nanosheets are prepared through a gas-phase phosphorization process. • P doping, defective structure, and interfaces are observed. • High freshwater/seawater oxidation activity occur on P-Fe 2 O 3 -CoP nanosheets. • P-Fe 2 O 3 -CoP nanosheets show high overall freshwater/seawater splitting activity. Tailoring surface composition and coordinative environment of catalysts in a nano-meter region often influence their chemical performance. It is reported that CoP exhibits a low dissociation ability of H–OH, originating from the poor desorption of intermediate species. Herein, we provide a feasible method to construct P-Fe 2 O 3 -CoP nanosheets through a gas-phase phosphorization process. P doping induces the formation of interfacial structure between Fe 2 O 3 and CoP and the generation of defective structures. The resulting P-Fe 2 O 3 -CoP nanosheets afford high freshwater/seawater oxidation activity (250/270 mV@10 mA/cm2) in 1 mol/L (M) KOH, which is even lower than commercial RuO 2. Compared with CoP||CoP, P-Fe 2 O 3 ||P-Fe 2 O 3 , and Co 3 O 4 ||Co 3 O 4 , the assembled P-Fe 2 O 3 -CoP||P-Fe 2 O 3 -CoP exhibits the superior water/seawater electrolysis performance with 1.61/1.65 V@10 mA/cm2. The synergistic effect of P doping, defective structure, and heterojunction leads to high water oxidation efficiency and water splitting efficiency. [ABSTRACT FROM AUTHOR]

Electron paramagnetic resonance (EPR) spectroscopy is a powerful tool for in situ/operando tracking of catalytic reactions that involve paramagnetic species either as a catalyst (e.g. transition metal ions or defects), reaction intermediates (radicals) or poisoning agents such as coke. This article provides a summary of recent experimental examples and developments in resonator design as well as detection schemes that were carried out in our group. Opportunities for applying this technique are illustrated by examples, including studies of transition metal exchanged zeolites and metal-free zeolites as well as metal oxide catalysts. The inherent limitations of EPR applied at high temperatures are discussed, as well as strategies in reducing or lifting these restrictions are evaluated and ideas for future improvements and methodologies are discussed.

Carbon nanospikes (CNSs) are a new nanomaterial that has enhanced surface roughness and surface oxide concentration, increasing the sensitivity for dopamine detection. However, CNS-modified electrodes (CNSMEs) have not been characterized for other neurochemicals, particularly those with higher oxidation potentials. The purpose of this study was to evaluate CNSMEs for the detection of adenosine, hydrogen peroxide (H2O2), and histamine. The sensitivity increased with CNSs, and signals at CNSMEs were about 3.3 times higher than CFMEs. Normalizing for surface area differences using background currents, CNSMEs show an increased signal of 4.8 times for adenosine, 1.5 times for H2O2, and 2 times for histamine. CNSMEs promoted the formation of secondary products for adenosine and histamine, which enables differentiation from other analytes with similar oxidation potentials. CNSs also selectively enhance the sensitivity for adenosine and histamine compared to H2O2. A scan rate test reveals that adenosine is more adsorption-controlled at CNS electrodes than CFMEs. CNSMEs are antifouling for histamine, with less fouling because the polymers formed after histamine electrooxidation do not adsorb due to an elevated number of edge planes. CNSMEs were useful for detecting each analyte applied in brain slices. Because of the hydrophilic surface compared to CFMEs, CNSMEs also have reduced biofouling when used in tissue. Therefore, CNSMEs are useful for tissue measurements of adenosine, hydrogen peroxide, and histamine with high selectivity and low fouling. [ABSTRACT FROM AUTHOR]

This paper deals with the synthesis conditions–defect formation relationship in zeolites. Silicalite‐1 (MFI‐type) is used as a model material. Samples synthesized from a system with high basicity (at 100 °C), a system with moderate basicity (at 150 °C), and a fluoride‐containing system in neutral medium (at 170 °C) are compared. Well‐crystallized materials with sizes ≈0.1, 1–10, and 30–40 µm are obtained. The samples are analyzed by complementary methods providing information on the short‐ and long‐range order in the zeolite framework. A strong correlation between the number of point defects in the zeolite framework and preparation conditions is established. Silicalite‐1 synthesized under mild synthesis conditions from a highly basic system exhibits a larger number of framework defects and thus low hydrophobicity. Further, the calcined samples are subjected to aluminum and silicon incorporation by postsynthesis treatment. The Al/Si incorporation in the zeolite framework and its impact on the physicochemical properties is studied by XRD, TEM/SEM, solid‐state NMR, FTIR, and thermogravimetric analyses. The defects healing as a function of the number of point defects in the initial material and zeolite crystal size is evaluated. The results of this study will serve for fine‐tuning zeolite properties by in situ and postsynthesis methods. [ABSTRACT FROM AUTHOR]

Abstract This paper deals with the synthesis conditions–defect formation relationship in zeolites. Silicalite‐1 (MFI‐type) is used as a model material. Samples synthesized from a system with high basicity (at 100 °C), a system with moderate basicity (at 150 °C), and a fluoride‐containing system in neutral medium (at 170 °C) are compared. Well‐crystallized materials with sizes ≈0.1, 1–10, and 30–40 µm are obtained. The samples are analyzed by complementary methods providing information on the short‐ and long‐range order in the zeolite framework. A strong correlation between the number of point defects in the zeolite framework and preparation conditions is established. Silicalite‐1 synthesized under mild synthesis conditions from a highly basic system exhibits a larger number of framework defects and thus low hydrophobicity. Further, the calcined samples are subjected to aluminum and silicon incorporation by postsynthesis treatment. The Al/Si incorporation in the zeolite framework and its impact on the physicochemical properties is studied by XRD, TEM/SEM, solid‐state NMR, FTIR, and thermogravimetric analyses. The defects healing as a function of the number of point defects in the initial material and zeolite crystal size is evaluated. The results of this study will serve for fine‐tuning zeolite properties by in situ and postsynthesis methods.

[Display omitted] • Acid treatment can partially remove organic linkers in the structure of MOF-808(Zr). • Rich defect sites can be created in tha structure of MOF-808(Zr) by acid treatment. • The acid-treated MOF-808(Zr) exhibits superior catalytic ODS performance. • The acid-treated MOF-808(Zr) is a heterogeneous catalyst and can be reused. The development of active oxidative desulfurization (ODS) catalysts is of practical importance. Recently, MOF-808(Zr) has been attempted to use as ODS catalyst due to its various advantages. However, generally MOF-808(Zr) prepared by conventional method was less active in the oxidation reactions due to the lack of defect sites in the structure. In this contribution, we report that the catalytic oxidative performance of MOF-808(Zr) can be enhanced by acid treatment due to the formation of defect sites resulting from the partial removal of organic linkers in the structure. During the experiment, the effect of acid concentration, treatment time, the addition amount of oxidant and reaction parameters on the performance of MOF-808(Zr) was studied. The catalytic results show that MOF-808(Zr) treated with 0.4 M HCl for 1h can catalyze the oxidation of dibenzothiophene completely at 60°C in 15 min. The activity (mole number of converted DBT per hour per unit mass) is 70 mmol h−1 g−1, which is much higher than that (45 mmol h−1 g−1) of parent MOF-808(Zr). In addition, the catalyst can be reused several times without obvious loss of catalytic performance. [ABSTRACT FROM AUTHOR]

Electron paramagnetic resonance (EPR) spectroscopy is a powerful tool for in situ/operando tracking of catalytic reactions that involve paramagnetic species either as a catalyst (e.g. transition metal ions or defects), reaction intermediates (radicals) or poisoning agents such as coke. This article provides a summary of recent experimental examples and developments in resonator design as well as detection schemes that were carried out in our group. Opportunities for applying this technique are illustrated by examples, including studies of transition metal exchanged zeolites and metal-free zeolites as well as metal oxide catalysts. The inherent limitations of EPR applied at high temperatures are discussed, as well as strategies in reducing or lifting these restrictions are evaluated and ideas for future improvements and methodologies are discussed., (Copyright 2024 Jörg Fischer, Mikhail Agrachev, Jörg Forrer, Rene Tschaggelar, Oliver Oberhänsli, Gunnar Jeschke. License: This work is licensed under a Creative Commons Attribution 4.0 International License.)

• The morphology and phase changes in γ-Al 2 O 3 during wet impregnation. • The morphology and phase changes are related with defect (AlV) sites on alumina. • Controlling the catalyst preparation is important to understand catalyst properties. The surface properties of support have a large influence on the catalyst properties and the catalyst properties are usually interpreted based on the characterization results of the support surface. However, in many cases, especially when γ-Al 2 O 3 is used as the support, the alumina surface can be changed during catalyst preparation. Here, the significant changes in the physical and chemical properties of γ-Al 2 O 3 were observed during catalyst preparation by using incipient wetness impregnation, which follows the general protocols of catalyst production. These changes were confirmed with transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. To investigate the origin of such changes from hydrolysis, low-crystalline γ-Al 2 O 3 (A600) was prepared, which has abundant defect sites (AlV) on its surface and bulk. Through 27Al magic angle spinning nuclear magnetic resonance (MAS-NMR) and XRD studies, it could be demonstrated that defect sites (AlV) play a crucial role in the hydrolysis of alumina. Further, the hydrolysis of the alumina surface could be controlled by altering the solvent properties like changing the volume ratio of ethanol. These results suggest that the change in the support's surface during the catalyst preparation should be considered carefully when correlating the characteristics of the alumina surface with the characteristics of an alumina-based catalyst. [ABSTRACT FROM AUTHOR]

Tuning the morphology of Ag3PO4 photocatalysts with an elevated concentration of KH2PO4 have been successfully conducted. This photocatalyst was prepared by starting material of AgNO3 and KH2PO4. The KH2PO4 aqueous solution with five concentrations of 0.10 M, 0.15 M, 0.30 M, 0.45 M, and 0.60 M was reacted with AgNO3 aqueous solution. The products were characterized using X-ray Diffraction (XRD), UV-Vis Diffuse Reflectance Spectroscopy (DRS), and Scanning Electron Microscopy (SEM). The concentration of KH2PO4 significantly affected the morphology, size, and crystallinity of catalyst. The morphology of Ag3PO4 may be tuned with the synthesis using an elevated concentration of KH2PO4. The sample with the synthesis using 0.15 M of KH2PO4 exhibited the excellent photocatalytic activity. The high photocatalytic activity was caused by the small size of mixed morphology of sphere and tetrahedron, high crystallinity and defect sites. Copyright © 2019 BCREC Group. All rights reserved. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Defect sites can have a greater influence on low-pressure CO 2 adsorption in MOFs than the co-adsorption of water. • CO 2 and H 2 O adsorption on UiO-66 MOF occurs non-ideally. • Molecular simulations accurately capture trends observed in experimentally measured CO 2 /H 2 O binary adsorption isotherms. Abstract Metal organic frameworks are frequently examined as potential solutions to complex gas phase separations problems. In many cases, the gas phase adsorption properties of these materials are quantified using single component gas adsorption isotherms and breakthrough experiments. In adsorption separations, however, it is common that the adsorbent participates in a multicomponent adsorption event. In the literature there is a general absence of multicomponent adsorption data with most data predicted via the Ideal Adsorbed Solution Theory or molecular simulations. Therefore, in this work, binary adsorption data of CO 2 and water on UiO-66 were measured experimentally using a volumetric method at three different water loadings. Molecular simulations of isotherms were compared to the experimental measurements and the impact of two different MOF defect sites on the multicomponent CO 2 /H 2 O adsorption behavior was determined. The experimental data show a slight enhancement of CO 2 loading when CO 2 is co-adsorbed with water, which is a result that was confirmed via molecular simulations. Also, the simulation results show that defect sites can have a greater influence on low-pressure CO 2 adsorption in MOFs than the co-adsorption of water. Furthermore, the simulations provide a molecular-level understanding of the role of these defects on the single and binary adsorption behavior. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hydrodeoxygenation of phenol at gas phase over Pd/Ce x Zr 1-x O 2 catalysts. • There is no correlation between oxygen vacancies amount and deoxygenation activity. • Deoxygenation is promoted by oxophilicity of the Zr4+/Zr3+ cations in the support. • The stronger interaction O - Zr4+/Zr3+ accumulate byproducts on catalyst surface. Abstract This work studies the effect of support defect sites on the performance of Pd/Ce x Zr 1-x O 2 (x = 0.00; 0.25; 0.50; 0.75; 0.90) catalysts for the hydrodeoxygenation of phenol in the gas phase at 573 K. The activity and selectivity for hydrodeoxygenation of phenol depends significantly on the support used. Increasing the Zr content from x = 0.0 to 0.5, the reaction rate for hydrodeoxygenation and the selectivity to benzene remains very low. However, upon increasing the Zr content above x = 0.5 a sudden jump in reaction rate and selectivity to benzene is observed. Interestingly, this activity and selectivity boost has no direct correlation with the density of acid sites or the concentration of defects on the support. Rather, the selectivity to deoxygenated products is found to depend on the oxophilicity of the support. Increasing the Zr content enhances the strength of the interaction between the O of the carbonyl group and the oxophilic site. It is proposed that the oxophilicity of these catalysts is related to the structure of the Ce x Zr 1-x O 2 solid solution formed. In addition, it is observed that the degree of deactivation during the reaction also depends on the Ce/Zr molar ratio of the support. Pd/ZrO 2 , Pd/Ce 0.10 Zr 0.90 O 2 and Pd/Ce 0.25 Zr 0.75 O 2 catalysts readily deactivate during reaction, whereas the phenol conversion only slightly decreases for Pd/CeO 2 , Pd/Ce 0.75 Zr 0.25 O 2 and Pd/Ce 0.50 Zr 0.50 O 2 catalysts. The results reveal that the density of Zr species on the surface is responsible for catalyst deactivation. The stronger adsorption between the oxygen from the phenol with Zr cations resulted in an accumulation of O-containing byproducts and catalyst deactivation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ceria based ozonation catalysts. • Ceria nanorods, nanocubes and nanooctahedra with different exposed facets. • OH, surface peroxide and atomic oxygen contributed to efficient catalytic activity. • Surface basicity and defects densities/oxygen vacancies. Abstract Ceria based catalysts have been widely applied in ozonation of organic pollutants in wastewater treatment. Ceria with different exposed facets have not been used in catalytic ozonation. In this study, ceria nanorods (R-CeO 2), nanocubes (C-CeO 2) and nanooctahedra (O-CeO 2) with different exposed facets (110) + (100), (100) and (111)) respectively were used in catalytic ozonation of p-nitrophenol. Two calcination temperatures 300 and 500 °C were selected for comparative catalytic activity. Ceria nanoparticles (NP-CeO 2) were also prepared for comparative catalytic activity. Approximately 86%, 71%, 68%, 64%, 60% and 40% TOC was removed by ozonation catalyzed by R300-CeO 2 , C300-CeO 2 , CeO 2 -NP, O300-CeO 2 , R500-CeO 2 and ozonation alone respectively. Nanorod calcined at 500 °C (R500-CeO 2) showed lower catalytic activity as compared to R300-CeO 2. O 3 was also rapidly decomposed by R300-CeO 2 as compared to other catalysts and single ozonation. Inorganic hydroxyl radical scavengers and several characterization techniques were applied for investigating the underlying mechanism of catalytic ozonation. Hydroxyl radicals, surface peroxide and surface atomic oxygen as reactive oxygen species were generated for enhancing the catalytic activity. Furthermore, irrespective of surface area, the difference in catalytic activity of ceria nanoshapes were assigned to the differences in the abundance of surface basic sites, defects densities/oxygen vacancies (OVs) and coordination number of surface atoms. This study provides an insight to use other metals with variety of exposed facets for catalytic ozonation. [ABSTRACT FROM AUTHOR]

Photocatalytic converting CO 2 into C 2 products is highly desirable but is extremely sensitive to catalyst structure. In this work, Ti-H species and oxygen vacancies are simultaneously integrated on hydrogenated SrTiO 3 surface by thermally treating with NaBH 4 , which promotes the activation of CO 2 into HCOO- and CO* intermediates. The proximity of oxygen vacancies and Ti-H species contributes to the C-C coupling of intermediates into acetylene (C 2 H 2) products. To the best of our knowledge, this is the first example for the photocatalytic CO 2 reduction into C 2 H 2 main products. The optimal hydrogenated SrTiO 3 has the C 2 H 2 yield of 39.0 μmol·g−1 with a 76.0 % selectivity among C 2 products. Therefore, this work provides an approach of designing the adjacent active sites for photocatalytic CO 2 conversion into C 2+ products. [Display omitted] • Hydrogenation induces Ti-H species and oxygen vacancies coexisting on SrTiO 3 surface. • Hydrogenated SrTiO 3 has a photocatalytic activity for the selective reduction of CO 2 into C 2 H 2. • The selectivity of C 2 H 2 is as high as 76 % in C 2 products. • The proximity of oxygen vacancies and Ti-H species plays a vital important role in C–C coupling. [ABSTRACT FROM AUTHOR]

The role of defects introduced into photocatalysts has been controversial, as some claim they serve as electron-trapping sites for improving the photogenerated charge separation, while others argue they act as exciton recombination centers to shorten the lifetime and mean free path of photocarriers. In the current study, we show the defect sites introduced into Zinc indium sulfide (ZIS) function as a double-bladed sword: on one hand, they act as recombination centers to impede photogenerated electron-hole separation in bulk ZIS; on the other hand, they drive electroless deposition and activation of the Pt co-catalyst through strong electronic coupling and thereby drastically enhance photocatalytic hydrogen production. As such, the defect-rich ZIS with a moderate Pt loading manifests the best hydrogen evolution rate of 15.56 mmol h−1 g−1 with a superb Pt-based TOF of 2334 h−1, apart from a high TON of 99610 in 92 h, which are among the best reported in literature for chalcogenide-based photocatalysts. Comprehensive microscopic, spectroscopic and photoelectrochemical characterizations unveil that the intimate coupling between the ZIS vacancy sites and deposited Pt atoms/clusters not only promotes photoexcited electron-hole separation, but also modulates local charge polarization to leverage the intrinsic activity of the co-catalyst. [Display omitted] • Different synthetic protocols result in different defect states of ZIS nanosheets. • Defects on ZIS nanosheets promote deposition and activation of the Pt co-catalyst. • A remarkable TOF of 2334 h−1 and TON of 99610 were achieved for photocatalystic hydrogen evolution. • Electronic coupling between ZIS and Pt at the defect sites promotes both the electro-kinetics and redox activity. • The double-edged role of defects in ZIS was explicitly clarified. [ABSTRACT FROM AUTHOR]

Collapsed titania nanotubes (cTiNT) were synthesized by the calcination of titania nanotubes (TiNT) at 650 °C, which leads to a collapse of their tubular morphology, a substantial reduction in surface area, and a partial transformation of anatase to the rutile phase. There are no significant changes in the position of the XPS responses for Ti and O on oxidation or reduction of the cTiNTs, but the responses are more symmetric than those observed for TiNTs, indicating fewer surface defects and no change in the oxidation state of titanium on oxidative and/or reductive pretreatment. The interaction of H2O and CO2 with the cTiNT surface was studied. The region corresponding to OH stretching absorptions extends below 3000 cm−1, and thus is broader than is typically observed for absorptions of the OH stretches of water. The exchange of protons for deuterons on exposure to D2O leads to a depletion of this extended absorption and the appearance of new absorptions, which are compatible with deuterium exchange. We discuss the source of this extended low frequency OH stretching region and conclude that it is likely due to the hydrogen-bonded OH stretches. Interaction of the reduced cTiNTs with CO2 leads to a similar but smaller set of adsorbed carbonates and bicarbonates as reported for reduced TiNTs before collapse. Implications of these observations and the presence of proton sources leading to hydrogen bonding are discussed relative to potential chemical and photochemical activity of the TiNTs. These results point to the critical influence of defect structure on CO2 photoconversion.

Defects in amorphous oxide thin-film transistor (TFT) influence major transistor parameters such as the threshold voltage, mobility, and subthreshold slope. Thus, understanding these defects is crucial in securing high-reliability and high-performance devices. However, only very limited electrical analysis methods such as multifrequency ${C}$ – ${V}$ and temperature-dependent ${I}$ – ${V}$ methods have been applied to accumulation mode devices and these do not provide direct pictures of the defects during carrier transport. In this investigation, we employed the discharging current analysis method to attain quantitative information involving the defect densities of amorphous hafnium–indium–zinc–oxide (a-HIZO) TFT. We were able to estimate the number of defect sites of a-HIZO TFT as being of the order of 1018/cm3, although this is dependent on the Hf content. We believe that this method can be widely used to estimate the defect density of oxide TFTs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The restructuring and degradation of OD-Cu during CO 2 reduction were revealed. • The C 2 + FE of OD-Cu decreased from 39.4% at 1 h to 26.0% at 5 h at −1.5 V vs. RHE. • Cu defect sites are easily dissolved during electrochemical CO 2 reduction. • Low-coordinated Cu defect sites are responsible for CO 2 reduction to C 2+ products. • The degradation can be circumvented and the FE of C 2+ products maintained at ca. 47.2% with the Cu redeposition process. Renewable energy produced through electrochemical CO 2 reduction is promising for mitigating the energy crisis and environmental issues. Notably, oxide-derived copper (OD-Cu) has attracted considerable attention owing to its unique ability to catalyze CO 2 electroreduction to >2e− products, especially C 2+ products, which are the key feedstocks for the chemical process. However, Cu under operating conditions usually leads to structure reconstruction and degradation, which hinders understanding the origin of its activity. Understanding the restructuring and degradation of OD-Cu catalyst to form C 2+ products is critical for understanding the active sites and, thus for designing effective and durable catalysts for CO 2 reduction. This paper describes that Cu defect sites are easily dissolved during electrochemical CO 2 reduction, and the presence of defect sites is strongly related to the catalytic performance of C 2+ products. Here, the C 2+ products Faradaic efficiency (FE) of OD-Cu decreased from 39.4% at 1 h to 26.0% at 5 h at −1.5 V vs. RHE, along with a decrease in low-coordinated defect sites. The low-coordinated defect sites facilitate CO adsorption and help to increase the CO coverage, thus promoting CO–CO coupling. The decrease in the number of defect sites and activity degradation is circumvented by promoting the Cu redeposition process. The C 2+ products FE of OD-Cu can be maintained at ca. 47.2% without an obvious decrease in CO 2 -saturated 0.1 M KHCO 3 with 1 mM Cu2+. The results of this study help in understanding the activity of OD-Cu and reveal its deactivation mechanism. This knowledge will aid in designing highly active and stable catalysts for CO 2 reduction. [ABSTRACT FROM AUTHOR]

Copper-ceria mixed oxides are widely considered promising catalysts for oxidation reactions, especially when the participation of lattice oxygen is required. However, the mechanistic understanding of these catalytic systems is still incomplete, due to their considerable complexity. In fact, copper doping of ceria results in the formation of a significant number of different interacting sites in continuous evolution during the catalytic processes. In the present study, pure and Cu-doped ceria samples were deeply investigated through combined spectroscopic techniques, i.e. XPS, EPR, and in situ FTIR and Raman spectroscopy. Through this systematic approach, the copper sites and lattice defects responsible for the enhanced CO oxidation activity of doped ceria were elucidated. Superficial Cu+ species and small Cu0 clusters promote the adsorption of CO at low temperature, while isolated Cu2+ monomers and dimers well-dispersed in the ceria matrix foster lattice oxygen mobility, involving the sub-surface in the redox phenomena. Consequently, the structure of Cu-doped ceria undergoes substantial modifications throughout CO oxidation in the absence of O 2 , with the formation of oxygen vacancy clusters. Anyway, these changes are reversible, and structural reorganization in the presence of O 2 can occur even at room temperature. The excellent performance of Cu-doped ceria eventually stems from the effective cooperation among the different catalytic sites in the mixed oxide. [Display omitted] • The different defects and Cu sites in doped ceria are complementarily investigated. • Cu+ sites and small Cu0 clusters at the catalyst surface enhance CO adsorption. • Isolated Cu2+ monomers and dimers in the CeO 2 matrix foster lattice oxygen mobility. • Clusters of oxygen vacancies may form when the oxygen demand at the surface is high. • The effective cooperation of the different sites promotes ceria catalytic activity. [ABSTRACT FROM AUTHOR]

Electrocatalysts with strong stability and high electrocatalytic activity have received increasing interest for oxygen reduction reactions (ORRs) in the cathodes of energy storage and conversion devices, such as fuel cells and metal-air batteries. However, there are still several bottleneck problems concerning stability, efficiency, and cost, which prevent the development of ORR catalysts. Herein, we prepared bimetal FeCo alloy nanoparticles wrapped in Nitrogen (N)-doped graphitic carbon, using Co-Fe Prussian blue analogs (Co3[Fe(CN)6]2, Co-Fe PBA) by the microwave-assisted carbon bath method (MW-CBM) as a precursor, followed by dielectric barrier discharge (DBD) plasma treatment. This novel preparation strategy not only possessed a fast synthesis rate by MW-CBM, but also caused an increase in defect sites by DBD plasma treatment. It is believed that the co-existence of Fe/Co-N sites, rich active sites, core-shell structure, and FeCo alloys could jointly enhance the catalytic activity of ORRs. The obtained catalyst exhibited a positive half-wave potential of 0.88 V vs. reversible hydrogen electrode (RHE) and an onset potential of 0.95 V vs. RHE for ORRs. The catalyst showed a higher selectivity and long-term stability than Pt/C towards ORR in alkaline media.

The cooperative effects of secondary mesoporosity and defects on the coke formation and deactivation of zeolite were investigated in n -pentane aromatization using model Ga/ZSM-5 catalysts. Mesoporosity was introduced to a commercial ZSM-5 by alkaline desilication, while the defects sites ( i.e. , internal silanols) in zeolites were annealed by the treatment with ammonium hexafluorosilicate. Aromatization after supporting Ga showed that the mesopore generation retarded catalyst deactivation via the suppression of internal coke formation while facilitating the external coke formation due to the enhanced diffusion of coke precursors (e.g ., alkylaromatics) out of zeolite micropores. Internal coke can cause a more severe deactivation than external coke because the acid sites are mainly located in the zeolite micropores. However, the mesopore generation alone could not efficiently reduce the total amount of coke deposition (it mainly changed the location of coke). In contrast, the annealing of internal silanols could suppress the overall coke formation. This phenomenon could be explained by the fact that coke precursors are initially generated at the zeolite internal defects, and then deposited as coke at either the internal or the external surfaces of the zeolite depending on the relative kinetics of coke precursor diffusion and its polymerization. Consequently, the catalyst with mesoporosity and annealed internal silanols exhibited the slowest catalyst deactivation due to the suppression of both internal and external coke depositions. [ABSTRACT FROM AUTHOR]

Ceria (CeO 2 ) and sodium-modified ceria (Ce-Na) were prepared through combustion synthesis. Palladium was deposited onto the supports (Pd/CeO 2 and Pd/Ce-Na) and their activity for the aqueous-phase transfer hydrogenation of phenol using 2-propanol under liquid flow conditions was studied. Pd/Ce-Na showed a marked increase (6×) in transfer hydrogenation activity over Pd/CeO 2 . Material characterization indicated that water-stable sodium species were not doped into the ceria lattice, but rather existed as subsurface carbonates. Modification of ceria by sodium provided more adsorption and redox active sites (i.e. defects) for 2-propanol dehydrogenation. This effect was an intrinsic property of the Ce-Na support and independent of Pd. The redox sites active for 2-propanol dehydrogenation were thermodynamically equivalent on both supports/catalysts. At high phenol concentrations, the reaction was limited by 2-propanol adsorption. Thus, the difference in catalytic activity was attributed to the different numbers of 2-propanol adsorption and redox active sites on each catalyst. [ABSTRACT FROM AUTHOR]

The combination of introducing mesopores and minimizing framework defects in zeolite catalysts has been proved to be highly effective in improving their catalytic lifetime in the MTH reaction. However, there is currently a lack of simple method to realize these two purposes at the same time. In this work, we report a simple one-step approach which not only completed the introduction of abundant mesopores into zeolite catalyst but also simultaneously realized the reduction of framework defects. Secondary template, fluoride media and post-treatment technology were not used during the synthetic process. As an example, a hierarchical ZSM-5 zeolite catalyst with low defect density was successfully synthesized. In the MTH reaction, the synergy effect of the hierarchical pore structure and the less framework defects endowed the prepared zeolite catalyst with a very long lifetime, which is 7.1 times that of the reference catalyst. [Display omitted] • A simple one-step approach for preparing hierarchical ZSM-5 zeolites with low defect density. • Secondary template, fluoride media and post-treatment technology are not used. • The prepared zeolite catalyst shows an extremely long lifetime during catalyzing MTH reaction. • The approach and the prepared catalyst are suitable for large-scale industrial applications. [ABSTRACT FROM AUTHOR]

To simultaneously achieve thorough purification of acetylene and maximum ethene increment, a sea urchinlike trimetallic PdAuAg mesocrystal catalyst as targeting sample and cuboctahedral trimetallic PdAuAg x and bimetallic catalyst as control samples were prepared by a co-reduction method, immobilized on MgAl hydrotalcite. Compared with bimetallic PdAu and PdAg catalysts, trimetallic PdAuAg x catalyst gave prior selectivity due to the positive synergetic effect. Significantly, PdAuAg 2 mesocrystal catalyst exhibited a turnover frequency of 0.063 s −1 , 46.5% higher than that of cuboctahedral PdAuAg 2 catalyst. A 76.2% ethene selectivity was achieved for the thorough purification of acetylene over PdAuAg mesocrystal catalyst with H 2 :C 2 H 2 of 2:1. Further improving H 2 :C 2 H 2 to 3, 76.5% yield can be maintained at 140 °C. Enhanced activity of the mesocrystal catalyst could be attributed to a high concentration of defect sites and a low activation barrier. Improved ethene selectivity could be ascribed to the increase in the (1 1 1)/(1 0 0) facets ratio and the formation of a Pd-C phase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single Cu atoms catalyst of Cu@UiO-66-(COOH) 2 was designed and synthesized. • High performance of LA hydrogenation to GVL was achieved via CTH route. • The defective sites in MOF facilitated the stabilization of Cu atoms. • The atomic dispersion of Cu and carboxyl group contributed to the high performance. Single-atom catalysts (SACs) have received great interests due to their high atomic utilization efficiency and unique electronic properties of active center atom. Here we reported a single-atom catalyst, Cu@UiO-66-(COOH) 2 , prepared by a simple, facile, and efficient solvothermal strategy, where Cu atoms were coordinated to the defect sites of secondary building units (SBUs) in a Zr-based metal–organic framework (MOF) UiO-66-(COOH) 2. The single-atom Cu@UiO-66-(COOH) 2 catalyst exhibited high activity for biomass derived platform chemical levulinic acid (LA) hydrogenation to γ-valerolactone (GVL) through catalytic transfer hydrogenation (CTH) process using isopropanol (IPA) as hydrogen donor under mild reaction conditions, where 96.7% GVL yield was achieved. The site isolation and uniform distribution of single Cu atoms combined with the aid of acid sites in MOF, attributing to the excellent catalytic performance for biomass upgrading. [ABSTRACT FROM AUTHOR]

As envisaged, a synthesis strategy is reported for encapsulating high index faceted trisoctahedral Au nanoparticles inside porous silica to preserve nanoparticle size by preventing sintering. Further, to probe the role of interfaces an active metal oxide junction was created by decorating trisoctahedral (TOH) Au nanoparticle with nano oxides before silica encapsulation. The activity of these catalysts was tested for CO oxidation reaction. The reaction was found to be facile on these encapsulated large structured Au nanoparticles showing appreciable activity at room temperature compared to non encapsulated counterparts. Apart from preventing sintering, the improved activity is demonstrated due to the retention of morphology and thereby the active centres due to encapsulation. [ABSTRACT FROM AUTHOR]

Creation of substrate-accessible interfacial defect sites will bring about new catalytic discoveries because substrate binding and activation on these sites are pivotal for controlling reaction intermediate and product selectivity. The partial oxidation of pristine Cu 2 O can lead to an excellent selective oxidation catalyst (CuO/Cu 2 O). The CuO/Cu 2 O, containing embedded CuO nanodomains on the surface and possessing abundant coordinatively unsaturated copper sites at the CuO Cu 2 O interface, shows very high activity toward C C bond cleavage and excellent selectivity toward formamides in trialkylamines oxidation. This result is exceptional because the previous works mainly offer dealkylated amines via C N bond cleavage. The unusual catalysis by CuO/Cu 2 O is attributed to the co-activation of oxygen and amines in close proximity at the CuO Cu 2 O interface. The present study contributes a new concept of delicate controlling substrate-accessible interfacial active sites on pristine oxide surfaces, and also offers a novel formamide synthesis method by trialkylamine oxidation. [ABSTRACT FROM AUTHOR]

Collapsed titania nanotubes (cTiNT) were synthesized by the calcination of titania nanotubes (TiNT) at 650 °C, which leads to a collapse of their tubular morphology, a substantial reduction in surface area, and a partial transformation of anatase to the rutile phase. There are no significant changes in the position of the XPS responses for Ti and O on oxidation or reduction of the cTiNTs, but the responses are more symmetric than those observed for TiNTs, indicating fewer surface defects and no change in the oxidation state of titanium on oxidative and/or reductive pretreatment. The interaction of H2O and CO2 with the cTiNT surface was studied. The region corresponding to OH stretching absorptions extends below 3000 cm-1, and thus is broader than is typically observed for absorptions of the OH stretches of water. The exchange of protons for deuterons on exposure to D2O leads to a depletion of this extended absorption and the appearance of new absorptions, which are compatible with deuterium exchange. We discuss the source of this extended low frequency OH stretching region and conclude that it is likely due to the hydrogen-bonded OH stretches. Interaction of the reduced cTiNTs with CO2 leads to a similar but smaller set of adsorbed carbonates and bicarbonates as reported for reduced TiNTs before collapse. Implications of these observations and the presence of proton sources leading to hydrogen bonding are discussed relative to potential chemical and photochemical activity of the TiNTs. These results point to the critical influence of defect structure on CO2 photoconversion. [ABSTRACT FROM AUTHOR]

We examined solution-processed alkaline-earth-metal doped gallium indium oxide (GIO) thin film transistors (TFT) and studied the relationship between the dopant species and the threshold voltage (V) stability. As the atomic number of the dopant increases, the amount of oxygen vacancies, which act as the major defect sites, decreased and the V stability is enhanced. The electron trapping times and total defect sites were quantitatively calculated. Particularly, Sr-doped GIO TFT show the highest V stability under positive gate bias and the origin of V stability enhancement is deduced by using the partial charge model and reaction kinetics. [ABSTRACT FROM AUTHOR]

Abstract: Three different techniques, a hydrothermal process with impregnation, solution-combustion and common precipitation with impregnation, were employed for the synthesis of 1.5wt% Pd/CeO2, and the resulting catalysts were denoted as Pd/HY, Pd/COM and Pd/PI, respectively. These catalysts have been investigated in terms of catalytic co-oxidation of CO and methanol and characterized by means of XRD, BET, SEM, STEM-EDS, CO chemisorption, XPS, Raman, O2-TPD, H2-TPR and CO-TPD measurements. Activity results show that a rapid catalytic oxidation of CO following the Mars-van Krevelen-type mechanism favors the complete methanol oxidation at low temperature. Consequently, the Pd/HY catalyst with the highest degree of defect sites connected with the mobility of activated oxygen shows the best catalytic performance. And the generation of more defect sites demonstrated by Raman is assumed for the low crystallinity and small crystallite size of CeO2 synthesized through a hydrothermal process while the high mobility of activated oxygen is evidenced by O2-TPD and H2-TPR. Additionally, the outstanding catalytic performance of Pd/HY is also associated with its high Pd dispersion and stable PdO x species as well as good redox behavior. [Copyright &y& Elsevier]

Abstract: Nanoporous carbon materials have attracted significant interests in the design of electrodes for electrocatalysis and biosensors. Here, three templated nanoporous carbons (TNCs) materials with substantial different specific surface area were designed and synthesized by a nanocasting method, in which mesoporous silicates and acid were used as template and catalyst, respectively. The TNCs were then used as electrode materials for simultaneous detection of dopamine (DA), ascorbic acid (AA) and uric acid (UA) at physiological pH. The correlations between specific surface area, edge-plane defect sites in TNCs and their distinguishing ability towards AA, DA, and UA were investigated. For TNCs with substantial larger specific surface area and more defect sites, the oxidation peaks of AA, DA and UA were separated well and their oxidation currents increased remarkably. A highly sensitive electrochemical sensor for simultaneous detection of those biomolecules was achieved by designing TNCs1 with the largest specific surface area and the most defect sites as the electrode material. The sensitivity of AA, DA and UA at the sensor is 0.012, 4.031, 0.605μA/μM respectively. Results suggest that TNCs1 is promising in biomolecules simultaneous detection. This work may also be valuable for scientists who search for excellent carbon materials for biosensing and electrocatalysis. [Copyright &y& Elsevier]

Abstract: Here we develop a facile process for preparing few-layer SnS2/graphene (FL-SnS2/G) hybrid by solution-phase method employing l-cysteine as a complexing, sulfide source and reducing agent. The FL-SnS2/G hybrid is characterized by XRD, SEM and HRTEM. It is demonstrated that the few-layer SnS2 with defects or disorder structure supports on graphene surface. Electrochemical tests show the FL-SnS2/G hybrid exhibits an extraordinary capacity of up to 920mAhg−1 with excellent cycling stability and high-rate capability. The significant improvement in the electrochemical performances is attributed to the robust composite structure and some synergistic interactions between few-layer SnS2 and graphene. Electrochemical impedance spectra confirm that the incorporation of graphene considerably improved the electric conductivity and electron rapid transfer of the FL-SnS2/G hybrid. Therefore, this new kind of FL-SnS2/G hybrid can be used as a promising anode material for lithium ion batteries. [Copyright &y& Elsevier]

Desulfurization of fuel oil is an indispensable step to obtain clean energy source. Design of bimetallic metal-organic frameworks (MOFs) with plentiful defects and highly dispersion active species, opens a new door to boost the catalytic activity for targeted reactions. In this work, we demonstrate a rapid green approach for fabricating bimetallic UiO-66(Hf-Zr) with highly dispersion of Hf/Zr-OH defect sites under solvent-free condition. UiO-66(0.13Hf-Zr) exhibited superior activity for oxidating sulfur compounds (1000 ppm S) of fuel oil at room temperature within 15 min. The turnover frequency (TOF) number reach 129.5 h-1 at 30 °C, which is 32.2 times higher than pristine UiO-66(Zr). Theoretical results reveal that the exposed Hf-OH sites readily react with H 2 O 2 to produce Hf-OOH intermediates which manipulate the reaction performance. Our work not only proposes a green solvent-free avenue for rapid preparation of defective bimetallic MOFs but also extends the application of bimetallic MOFs in the field of desulfurization. [Display omitted] • A rapid solvent-free approach for fabricating bimetallic UiO-66(Hf-Zr) with highly dispersion of Hf/Zr-OH defects has been developed. • UiO-66(0.13Hf-Zr) exhibited superior activity for oxidating sulfur compounds (1000 ppm S) of fuel oil at room temperature within 15 min. • The TOF value can reach 129.5 h-1 at 30 °C, and rise up to 487.7 h-1 at 50 oC, outperforming most of the reported ODS catalysts. • Theoretical study indicated that the exposed Hf-OH sites readily react with H 2 O 2 to produce Hf-OOH intermediates and manipulate the ODS rate. • UiO-66(0.13Hf-Zr) also displayed extraordinary activity in acetalization and the oxidation of styrene and benzyl alcohol at room temperature. [ABSTRACT FROM AUTHOR]

Abstract: With density functional calculations and in situ 29Si and 31P MAS NMR experiments, a novel defect site (defect site II, dsII) was identified in titanium silicalite molecular sieve (TS-1 zeolite), supported by the previous experimental results. The conversion from Q3 species [(SiO)3Si(OH)] into Q4-like species [Si(OSi)4] due to TMP adsorption indicated the presence of Brönsted acidity in TS-1 zeolite. The thermodynamic analysis and Ti/Si substitution energies further confirmed that the proton transferring process of defect site II is much facilitated in TS-1 zeolite whereas on the contrary in silicalite-1. With the proton-affinity calculations, the Brönsted acidities of several cation-doped zeolites were found to decrease in the order of Al-ZSM-5>Fe-ZSM-5>B-ZSM-5>TS-1. The Brönsted acidity of TS-1 zeolite is even weaker than that of B-ZSM-5 zeolite, suggesting the potential role as a new acid catalyst. As to silicalite-1, its acidity is even weaker than that of defect site I (dsI) in TS-1 zeolite. [Copyright &y& Elsevier]

Abstract: Near-surface alloys (NSAs) possess a variety of unusual catalytic properties that could make them useful candidates for improved catalysts in a variety of chemical processes. It is known from previous work, for example, that some NSAs bind hydrogen very weakly while, at the same time, permitting facile H2 activation. These NSAs could, potentially, facilitate highly selective hydrogenation reactions at low temperatures. In the present work, the suitability of NSAs for use as hydrogen fuel cell anodes has been evaluated; the combination of properties, possessed by selected NSAs, of weak binding of CO with relatively facile H2 activation is nearly ideal for this application. We suggest that, as nanoscale materials synthesis techniques improve, it will become feasible to reproducibly prepare NSAs with highly specified surface structures, resulting in the design and manufacture of a wide variety of such materials for use in fuel cells and in an ever-increasing range of catalytic applications. Furthermore, we introduce a new concept for NSA-defect sites, which could be responsible for the promotional catalytic effects of a second metal added, even in minute quantities, to a host metal catalyst. [Copyright &y& Elsevier]

The present work focuses on Raman and photoluminescence spectroscopic study of spin coated Nd doped titania thin films annealed at 350 and 450 ​°C. For all the samples, the penetration depth of laser was evaluated to be about 300–350 ​nm. The lifetime of phonon was in the range 0.46–0.52 ps for different samples and its variation is discussed in detail. Photoluminescence (PL) spectra of Nd doped titania revealed the influence of dopant concentration on defect sites and strong emission in near infrared (NIR) region confirms Nd doping in titania matrix. The effect of Nd doping on photocatalytic behavior of titania films was studied by degrading methyl orange (MO) under UV light. The Nd doped titania thin films enhance the photocatalytic activity as compared to pristine titania. The enhancement in efficiency is correlated to the formation of surface defects. Energy transformation mechanism between titania and Nd, causing Nd related emission. [Display omitted] • A Nd doped titania thin film photocatalyst was prepared using spin coating method. • The Raman scattering study illustrates influence of Nd dopant on structural properties of the films. • The origin of Nd related emission in infra-red region confirms the doping of Nd in titania matrix. • The photocatalytic activity was found to be high for 0.4 ​at% Nd doped sample annealed at 450 ֯C. [ABSTRACT FROM AUTHOR]

• Silica-zirconia catalyst was dried via microwave (MW) and conventional oven (CO). • MW drying time was reduced by six times and used three times less energy than CO. • Fast MW drying promoted oxygen vacancy (OV) and metal defect sites (MSD) formation. • OV and MSD acts as an electron acceptor to inhibit electron-hole pairs recombination. • SZN-M gave the highest photocatalytic degradation of toxic 2-chlorophenol (92%). The work aims to evaluate the efficient microwave (MW) drying method of silica-doped tetragonal zirconia nanocatalysts (SZN-M) for intensification of the degradation of toxic chlorophenolic compounds. The catalyst dried under a conventional oven (SZN-O) was also conducted for comparison. The MW drying time was reduced six times and three times less energy was used than the conventional oven drying. The catalysts were characterized by Fourier-transform infrared, X-ray diffraction, electron spin resonance, nitrogen adsorption-desorption analyses, zeta potential, ultraviolet–visible diffuse reflectance spectroscopy and photoluminescence analyses. Compared with SZN-O, the SZN-M possessed a higher number of Si-O-Zr bonds that led to a greater amount of oxygen vacancies, metal defect sites, larger pore size as well as surface area, and hence displayed excellent performance toward the degradation of toxic 2-chlorophenol, 2-CP (92%), while only 67% for the former. The SZN-M achieved to reduce the total organic carbon and biological oxygen demand up to 88% and 89%, respectively, while for SZN-O, the reduction was up to 82% and 84%. The catalysts still remained active after five cycles and are highly capable of degrading various chlorophenolic compounds that could be very beneficial for the wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Defect modified UiO-66 supported Au nanoparticles exhibited excellent catalytic performance in the oxidative esterification of benzyl alcohol with methanol under mild conditions. The defects were generated by introducing HCl during the preparation procedure. The defects exposed the Lewis acid of coordinatively unsaturated metal sites, which is benefit for Au loading and changing Au nanoparticles (NPs) to a negative electron state. The negatively charged Au nanoparticle promoted the reaction by strong oxygen activation ability. The present study could help to unravel the synergistic effect of support and metal interaction and provides an efficient photocatalytic route for synthesis high-value esters in terms of sustainable chemistry. Unlabelled Image • Defective UiO-66 supported AuNPs exhibits high photocatalytic performance in the oxidative esterification of alcohols. • Defects in UiO-66 favor loading Au NPs and leading negatively charged Au NPs. • The Lewis acidic sites origined from defects enhance the adsorption of reactants. • Light adsorption of Au NPs via LSPR effect improve the catalytic activity. [ABSTRACT FROM AUTHOR]

• CO oxidation was studied by in situ Raman spectroscopy on nanostructured ceria-based materials. • In situ Raman analyses during CO oxidation allowed to monitor defect sites in operando conditions. • Cycles of reduction (CO in N 2) and oxidation (pure O 2) at 400 °C allow to study the stability of defects. • Oxygen vacancies evolved from clusters to isolated ones according to the atmosphere and temperature. • The involvement of the defect sites in structural rearrangement is fostered by easily reducible dopants. Among the factors affecting ceria activity, the defectiveness plays a key role in the case of CO oxidation. In this study, its connection with the catalytic performance was investigated via in-situ Raman spectroscopy on nanostructured pure and Cu/Mn-doped ceria, monitoring the defect sites and surface species evolution during the reaction. The accumulation of polyene-like chains, formed through CO dissociative adsorption at the catalyst surface, was observed and their disappearance was related to the catalyst light-off temperature. Moreover, the doped samples exhibited a rise of the Raman bands associated to defects after the tests, consequence of the structural rearrangements occurring during CO oxidation. Indeed, in-situ Raman measurements during reduction (CO/N 2) and oxidation cycles at 400 °C evidenced the formation of oxygen vacancy clusters in reducing atmosphere, which could reorganize not only in O 2 but also upon a temperature decrease, forming isolated vacancies and then evolving in Frenkel and extrinsic oxidized dopant-containing sites when exposed to oxygen. [ABSTRACT FROM AUTHOR]

We design a facial and efficient strategy to synthesize N,P-doped defective carbon nanosheets first (N,P-DC), and then cover doped sites with well-define metal-N 4 organic macrocyclic molecules (FePc@N,P-DC) through non-pyrolysis process. The catalyst presents superior ORR and OER activity and stability. • We cover doped sites in N,P-doped defective carbon nanosheets with FePc molecules (FePc@N,P-DC) through non-pyrolysis process. • The catalyst delivers superior ORR performances with the half-wave potential of 0.903 V and excellent cycling-life stability. • DFT calculations suggest that the covering FePc molecules downhill the overpotential of N,P-DC for ORR (0.80–0.52 V) • Zn-air batteries (ZABs) are assembled for practical application. Experimental and computational studies show that topological defect and FeN 4 site in carbon materials would deliver high performances for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Either defect or FeN 4 site attracts numerous discussion, however, the synergetic effect between them is hardly explored. Herein, we design a facial strategy to synthesize N,P-doped defective carbon nanosheets first (N,P-DC), then cover doped sites with well-define metal-N 4 macrocyclic molecules (FePc@N,P-DC) through non-pyrolysis process. The defective carbon boosts the high spin state of Fe center, thus brings superior ORR performances with the half-wave potential of 0.903 V and excellent cycling-life stability in alkaline media. Theoretical calculations show that the overpotential of FePc@N,P-DC for ORR is 0.52 V, much lower than 0.80 V (N,P-DC). Interestingly, the OER activity is simultaneously improved. This metal-Pc@defective carbon hybrid opens a door to develop electrocatalysts combining atomically metal-N 4 sites with topological defect towards diverse energy conversion type. [ABSTRACT FROM AUTHOR]

The emergence of life on Earth (and elsewhere) must have occurred in a milieu that is far from equilibrium, such as at alkaline hydrothermal vents that would have harboured built-in gradients in temperature, redox potential and pH along with precipitated iron-bearing minerals capable of separating these gradients, concentrating reactants and catalysing requisite protobiotic reactions. Iron-bearing minerals such as mackinawite, greenalite and fougèrite have been investigated as catalysts for protobiotic reactions, including amino acid synthesis. In the field of heterogeneous catalysis, it is well known that defect sites in the crystal structure are often the most active sites for catalysis, and mineral catalysts that have been exposed to ionizing radiation are known to exhibit increased reactivity due to radiation-induced defect sites. In this work, we (i) review the literature on the radioactive environment of the Hadean era, (ii) highlight the role of radionuclide ionizing radiation from 238 U, 232 Th and 40 K in generating defect sites with high catalytic activity for the chemical evolution of organic molecules, and (iii) hypothesize that these processes accelerated the emergence of life., Competing Interests: I declare I have no competing interests., (© 2019 The Author(s).)