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Bioorthogonal metallocatalysis has opened up a xenobiotic route to perform nonenzymatic catalytic transformations in living settings. Despite their promising features, most metals are deactivated inside cells by a myriad of reactive biomolecules, including biogenic thiols, thereby limiting the catalytic functioning of these abiotic reagents. Here we report the development of cytocompatible alloyed AuPd nanoparticles with the capacity to elicit bioorthogonal depropargylations with high efficiency in biological media. We also show that the intracellular catalytic performance of these nanoalloys is significantly enhanced by protecting them following two different encapsulation methods. Encapsulation in mesoporous silica nanorods resulted in augmented catalyst reactivity, whereas the use of a biodegradable PLGA matrix increased nanoalloy delivery across the cell membrane. The functional potential of encapsulated AuPd was demonstrated by releasing the potent chemotherapy drug paclitaxel inside cancer cells. Nanoalloy encapsulation provides a novel methodology to develop nanoreactors capable of mediating new-to-life reactions in cells., UK Research & Innovation (UKRI), Engineering & Physical Sciences Research Council (EPSRC) EP/N021134/1, ERC (Advanced Grant CADENCE) ERC-2016-ADG-742684, European Commission European Commission Joint Research Centre H2020-MSCA-IF-2014-658833 H2020-MSCA-IF-2018-841990 H2020-MSCA-IF-2016-749299 H2020-MSCA-IF-2019-895664, Spanish Government RTI2018-099019-A-I00

Controlling the nano- and micropatterning of metal structures is an important requirement for various technological applications in photonics and biosensing. This work presents a method for controllably creating silver micropatterns by laser-induced photosculpting. Photosculpting is driven by plasmonic interactions between pulsed laser radiation and silver nanorods (AgNRs) in aqueous suspension; this process leads to optical binding forces transporting the AgNRs in the surroundings, while electronic thermalization results in photooxidation, melting, and ripening of the AgNRs into well-defined 3D structures. This work call these structures Airy castles due to their structural similarity with a diffraction-limited Airy disk. The photosculpted Airy castles contain emissive Ag nanoclusters, allowing for the visualization and examination of the aggregation process using luminescence microscopy. This work comprehensively examines the factors that define the photosculpting process, namely, the concentration and shape of the AgNRs, as well as the energy, power, and repetition rate of the laser. Finally, this work investigates the potential applications by measuring the metal-enhanced luminescence of a europium-based luminophore using Airy castles., MCIN/AEI/10.13039/501100011033 and the European Regional Development Fund (ERDF). Grant Number: CTQ2017-85658-R MCIN/AEI/10.13039/501100011033. Grant Number: PID2020-114256RB-I00 European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie. Grant Number: 101007934 Fundação para a Ciência e a Tecnologia, I.P. Grant Numbers: UIDB/00100/2020, 2022.04076.PTDC

Ethylene oxide is one of the most important raw materials in the chemical industry, with an annual production close to 35 million metric tons. Despite its importance, to date, no metal has been found that can compete with the original silver bulk material catalyst discovered in 1931. Recently, a few copper and copper–silver based nanostructures have demonstrated remarkable selectivity and activity, especially when coupled with an industrial chlorine promoter. The present work evaluates the mechanistic role of chlorine as an active promoter of the selective oxidation of ethylene to ethylene oxide in the presence of a silver–copper oxide hybrid nanocatalyst (AgCuO). Experimental kinetic studies combined with density functional theory (DFT) calculations provide insight into the influence that Ag/CuO-supported chlorine atoms have over the ethylene epoxidation reaction. Remarkably, the typically described indirect route via the formation of an oxametallacycle (OMC) is also accompanied by a direct route. Furthermore, the presence of chlorine seems to facilitate a more favorable adsorption energy for ethylene oxide (EO) than for acetaldehyde (AA), the main reaction by-product. As a result, complete oxidation of EO can be further prevented in the presence of this AgCuO hybrid heteronanostructure., We acknowledge financial support from the European Research Council ERC-Advanced Grant HECTOR (project number 267626) is gratefully acknowledged. The computations were performed on resources provided by the supercomputer “Caesaraugusta” (node of the Spanish Supercomputer Network) provided by BIFI (Universidad de Zaragoza). The TEM studies were conducted at the Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Spain. S.H. acknowledges funding from the Agencia Estatal de Investigación and the Ministerio de Ciencia, Innovación y Universidades, of Spain (PID2019-110430G B-C22), and from the EU FEDER Framework 2014-2020 and Consejería de Conocimiento, Investigación y Universidad of the Andalusian Government (FEDER-UPO-1265695).

Cancer represents a major public health issue and a primary cause of death for the mankind and the search for alternative cancer treatments that assist or alleviate the drawbacks of current cancer therapies remains imperative. Nanocatalytic medicine represents a new discipline that aims at exploiting the unique response of heterogeneous catalysts exposed to unconventional conditions such as those encountered in the tumor microenvironment (TME). Photo-triggered cancer therapies using light-activable catalytic materiales can stimulate and activate multiple biological processes and represent a very promising field of study. Herein, we evaluate the use of carbon nanodots with different composition (CNDs) retrieved by laser pyrolysis as potential near-infrared (NIR) photosensitizers able to activate P25 semiconductor nanostructured photocatalysts. We describe the enhanced photocatalytic response towards glucose conversion and reactive oxygen species (ROS) generation upon irradiation with NIR-LEDs when CNDs doped with heteroatoms were tested. The most active photocatalysts were evaluated in the presence of cancer cells and revealed a promising photodynamic effect under NIR irradiation. This work represents one of the scarce examples of a conventional inorganic photocatalyst containing TiO2 that is translated into a biomedical application with a successful outcome.

Platinum nanoparticles (Pt NPs) have a well-established role as a classic heterogeneous catalyst. Also, Pt has traditionally been employed as a component of organometallic drug formulations for chemotherapy. However, a new role in cancer therapy is emerging thanks to its outstanding catalytic properties, enabling novel approaches that are surveyed in this review. Herein, we critically discuss results already obtained and attempt to ascertain future perspectives for Pt NPs as catalysts able to modify key processes taking place in the tumour microenvironment (TME). In addition, we explore relevant parameters affecting the cytotoxicity, biodistribution and clearance of Pt nanosystems. We also analyze pros and cons in terms of biocompatibility and potential synergies that emerge from combining the catalytic capabilities of Pt with other agents such as co-catalysts, external energy sources (near-infrared light, X-ray, electric currents) and conventional therapies., The authors gratefully acknowledge funding from the European Commission (ERC Advanced Grant-742684 CADENCE).

The use of inorganic nanomaterials to tackle and exploit the intrinsic chemical nature of the tumor microenvironment (TME) has emerged as a promising strategy in cancer therapy. Manganese oxide nanoparticles (MnxOy) offer unique advantages in terms of redox properties and specificity towards the TME scenario: low O2 concentrations, mildly acidic pH and high oxidative stress; environmental conditions that often lead to a reduction in the efficacy of cancer treatments. MnxOy-based nanoplatforms have recently demonstrated exciting properties as inorganic nanocatalysts to operate under TME constraints. Alternatively, Mn-nanocatalysts have also displayed synergistic anticancer response in combination with other active co-adjuvant elements (drugs, enzymes or nanomaterials). The aim of this review is to provide new insights on the main functionalities of Mn-based nanomaterials applied to cancer therapy. We analyze its capacity as oxygen supplier in hypoxic scenarios, its role to induce the selective depletion of glutathione (GSH) to maximize cell stress or its capacity to promote starvation therapy via glucose oxidation. We aim at providing an insightful view of the operating mechanisms behind each of these critical processes and highlight the versatility and catalytic richness of Mn-based nanoparticles in this developing field. We also provide a general and comprehensive analysis of the Mn fate when trafficking through the intracellular levels., Financial support from the European Research Council (ERC Advanced Grant CADENCE number 742684) is gratefully acknowledged. J.B-A. thanks the Spanish Government for an FPU predoctoral contract.

Heterogeneous catalysis has emerged as a promising alternative for the development of new cancer therapies. In addition, regarding the tumor microenvironment as a reactor with very specific chemical features has provided a new perspective in the search for catalytic nanoarchitectures with specific action against chemical species playing a key role in tumor metabolism. One of these species is glutathione (GSH), whose depletion is the cornerstone of emerging strategies in oncology, since this metabolite plays a pivotal regulatory role as antioxidant agent, dampening the harmful effects of intracellular reactive oxidative species (ROS). Herein, we present copper-iron oxide spinel nanoparticles that exhibit a versatile and selective catalytic response to reduce GSH levels while generating ROS in a cascade reaction. We demonstrate a clear correlation between GSH depletion and apoptotic cell death in tumor cells in the presence of the copper-iron nanocatalyst. Furthermore, we also provide a novel analytical protocol, alternative to state-of-the-art commercial kits, to accurately monitoring the concentration of GSH intracellular levels in both tumor and healthy cells. We observe a selective action of the nanoparticles, with lower toxicity in healthy cell lines, whose intrinsic GSH levels are lower, and intense apoptosis in tumor cells accompanied by a fast reduction of GSH levels., Financial support from the European Research Council (ERC-Advanced Grant CADENCE number 742684) is gratefully acknowledged. The TEM measurements were conducted at the Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Spain. The synthesis of materials has been performed by the Platform of Production of Biomaterials and Nanoparticles of the NANBIOSIS ICTS, more specifically by the Nanoparticle Synthesis Unit of the CIBER in BioEngineering, Biomaterials & Nanomedicine (CIBER-BBN). J.B-A. acknowledges the Spanish Government for an FPU predoctoral contract. We would also like to thank to the Scientific Services of the Aragon Institute of Health Sciences (IACS), specifically to the Cell culture, Microscopy, and Citometry Services and their specialist and the ICTS ELECMI.

This article belongs to the Special Issue 10th Anniversary of Catalysts—Feature Papers in Photocatalysis., The present review aims at highlighting recent advances in the development of photocatalysts devoted to cancer therapy applications. We pay especial attention to the engineering aspects of different nanomaterials including inorganic semiconductors, organic-based nanostructures, noble metal-based systems or synergistic hybrid heterostructures. Furthermore, we also explore and correlate structural and optical properties with their photocatalytic capability to successfully performing in cancer-related therapies. We have made an especial emphasis to introduce current alternatives to organic photosensitizers (PSs) in photodynamic therapy (PDT), where the effective generation of reactive oxidative species (ROS) is pivotal to boost the efficacy of the treatment. We also overview current efforts in other photocatalytic strategies to tackle cancer based on photothermal treatment, starvation therapy, oxidative stress unbalance via glutathione (GSH) depletion, biorthogonal catalysis or local relief of hypoxic conditions in tumor microenvironments (TME)., This research was funded by the European Research Council (ERC) through an Advanced Research Grant (CADENCE, grant number 742684). J.B.-A. acknowledges the Spanish Government for a PhD predoctoral grant (FPU18/04618). J.I.G.-P. thanks the Regional Government of Aragon (DGA) for granting a PhD predoctoral contract.

The present work sheds light on a generally overlooked issue in the emerging field of bio-orthogonal catalysis within tumour microenvironments (TMEs): the interplay between homogeneous and heterogeneous catalytic processes. In most cases, previous works dealing with nanoparticle-based catalysis in the TME focus on the effects obtained (e.g. tumour cell death) and attribute the results to heterogeneous processes alone. The specific mechanisms are rarely substantiated and, furthermore, the possibility of a significant contribution of homogeneous processes by leached species – and the complexes that they may form with biomolecules – is neither contemplated nor pursued. Herein, we have designed a bimetallic catalyst nanoparticle containing Cu and Fe species and we have been able to describe the whole picture in a more complex scenario where both homogeneous and heterogeneous processes are coupled and fostered under TME relevant chemical conditions. We investigate the preferential leaching of Cu ions in the presence of a TME overexpressed biomolecule such as glutathione (GSH). We demonstrate that these homogeneous processes initiated by the released by Cu–GSH interactions are in fact responsible for the greater part of the cell death effects found (GSH, a scavenger of reactive oxygen species, is depleted and highly active superoxide anions are generated in the same catalytic cycle). The remaining solid CuFe nanoparticle becomes an active catalyst to supply oxygen from oxygen reduced species, such as superoxide anions (by-product from GSH oxidation) and hydrogen peroxide, another species that is enriched in the TME. This activity is essential to sustain the homogeneous catalytic cycle in the oxygen-deprived tumour microenvironment. The combined heterogeneous–homogeneous mechanisms revealed themselves as highly efficient in selectively killing cancer cells, due to their higher GSH levels compared to healthy cell lines., Financial support from the European Research Council (ERC Advanced Grant CADENCE number 742684) is gratefully acknowledged. The TEM measurements were conducted at the Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia y Materiales de Aragon, Universidad de Zaragoza, Spain. The synthesis of materials has been performed by the Platform of Production of Biomaterials and Nanoparticles of the NANBIOSIS ICTS, more specifically by the Nanoparticle Synthesis Unit of the CIBER in BioEngineering, Biomaterials & Nanomedicine (CIBER-BBN). J. B.-A. acknowledges the Spanish Government for an FPU predoctoral contract. M. E. acknowledges the Diputacion General de Aragon (DGA) for a predoctoral contract. The authors thank Dr Javier Calzada and Dr Silvia Irusta for their help with UPLC and XPS data acquisition. E. P. U. thanks Gobierno de Aragón-FSE (Spain, grupo Aminoácidos y Péptidos, E19_20R) for funding.

Chapter 9., The present chapter overviews the role of iron-based nanoparticles as enzyme-mimicking surrogates and their potential role in tumor microenvironments. The unique and challenging chemical features surrounding the tumor environment make necessary the development of robust and versatile catalytic platforms. Fe-based catalysts can selectively induce a series of adverse reactions for minimizing cancer cell’s proliferation and survival. Recently, the development of inorganic nanomaterials with enzyme-like properties that can outperform or complement the role of natural enzymes is being the subject of intense research. Herein, we highlight the relevance of different Fe-based nanocatalysts and provide a deeper insight of the reaction mechanisms behind their unique capability to catalyze a wide variety of enzymatic reactions of interest and potential for the development of alternative cancer therapies. Furthermore, the most recent advances on single-atom catalysts have been also summarized and highlighted.

The present work sheds light on a generally overlooked issue in the emerging field of bio-orthogonal catalysis within tumor microenvironments (TMEs): the interplay between homogeneous and heterogeneous catalytic processes. In most cases, previous works dealing with nanoparticle-based catalysis in the TME, focus on the effects obtained (e.g. tumor cell death) and attribute the results to heterogeneous processes alone. The specific mechanisms are rarely substantiated and, furthermore, the possibility of a significant contribution of homogeneous processes by leached species –and the complexes that they may form with biomolecules- is neither contemplated nor pursued. Herein, we have designed a bimetallic catalyst nanoparticle containing Cu and Fe species and we have been able to describe the whole picture in a more complex scenario where both homogeneous and heterogeneous processes are coupled and fostered under TME relevant chemical conditions. We investigate the preferential leaching of Cu ions in the presence of a TME overexpressed biomolecule such as glutathione (GSH). We demonstrate that these homogeneous processes initiated by the released by Cu-GSH interactions are in fact responsible for the greater part of the cell death effects found (GSH, a scavenger of reactive oxygen species is depleted and highly active superoxide anions are generated in the same catalytic cycle). The remaining solid CuFe nanoparticle becomes an active catalase-mimicking surrogate able to supply oxygen from oxygen reduced species, such as superoxide anions (by-product from GSH oxidation) and hydrogen peroxide, another species that is enriched in the TME. This enzyme-like activity is essential to sustain the homogeneous catalytic cycle in the oxygen-deprived tumor microenvironment. The combined heterogeneous-homogeneous mechanisms revealed themselves as highly efficient in selectively killing cancer cells, due to their higher GSH levels compared to healthy cell lines.

Microwave-assisted gas-phase conversion on structured catalysts is emerging as a promising process intensification technology in the field of heterogeneous catalysis. The combination of selective heating and structured catalytic materials induces a temperature difference between the heated catalytic sample and the surrounding void regions to avoid non-selective gas-phase reactions. This operational principle allowed inhibiting thermal cracking in alkane dehydrogenation processes as well as retarding catalyst deactivation by coking in methane dehydroaromatization (MDA) processes. However, its effectiveness has not been reported so far out of the laboratory scale conditions. This work addresses the scaling of the microwave-assisted MDA process from lab scale experiments to a scaled-up configuration capable of stable operation with a 150-fold higher feeding rate. The scaling-up potential and main obstacles to overcome for this technology are critically discussed. In addition, a techno-economic assessment of the MW-MDA process is presented. The catalytic activity was kept for seven consecutive reaction cycles, i.e. 35 h MW-MDA, prior to a progressive decay due to permanent deactivation caused by zeolite dealumination and active metal loss. The scaled set-up operated for up to 295 consecutive hours under unmanned operation conducting 4 -h MDA-regeneration cycles on Mo/ZSM-5@SiC monoliths and resulting in 125-fold increase of converted methane and a 450-fold increase of benzene (0.17 LC6H6/h) in comparison with the laboratory scale tests. Scaled set-up experiments were run using only a 6-fold microwave input power, thus, highlighting the non-linearity between energy consumption and scaling factor for this technology and the importance of microwave cavity design., Financial support from the European Union’s Horizon 2020 Research and Innovation Programme (ADREM project – Grant Agreement No. 680777) is gratefully acknowledged.

Photocatalytic gas-phase hydrogenation of CO2 into alkanes was achieved over TiO2-supported Ni nanoparticles under LED irradiation at 365 nm, 460 nm and white light. The photocatalysts were prepared using photo-assisted deposition of Ni salts under LED irradiation at 365 nm onto TiO2 P25 nanoparticles in methanol as a hole scavenger. This procedure yielded 2 nm Ni particles decorating the surface of TiO2 with a nickel mass content of about 2%. Before the photocatalytic runs, Ni/TiO2 was submitted to thermal reduction at 400 °C in a 10% H2 atmosphere which induced O-defective TiO2−x substrates. The formation of oxygen vacancies, Ti3+ centers and metallic Ni sites upon photocatalytic CO2 hydrogenation was confirmed by operando EPR analysis. In situ XPS under reaction conditions suggested a strong metal–support interaction and the co-existence of zero and divalent Ni states. These photoactive species enhanced the photo-assisted reduction of CO2 below 300 °C to yield CO, CH4 and C2H6 as final products., Financial support from the Spanish Ministry of Science and Universities through the CTQ2016-77144-R research project is gratefully acknowledged. We thank Dr Irusta for her assistance in preliminary XPS measurements. The synthesis of materials was performed by the Platform of Production of Biomaterials and Nanoparticles of the NANBIOSIS ICTS, more specifically by the Nanoparticle Synthesis Unit of the CIBER in Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN). The TEM studies were conducted at the Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Spain. The EPR characterization was performed at the Centre for Catalysis and Sustainable Chemistry, Technical University of Denmark, supported by the Department of Chemistry for a PhD project to D. N. and by the Carlsberg Foundation for instrumentation.

Plasmonic photocatalysts combining metallic nanoparticles and semiconductors have been aimed as versatile alternatives to drive light-assisted catalytic chemical reactions beyond the ultraviolet (UV) regions, and overcome one of the major drawbacks of the most exploited photocatalysts (TiO2 or ZnO). The strong size and morphology dependence of metallic nanostructures to tune their visible to near-infrared (vis-NIR) light harvesting capabilities has been combined with the design of a wide variety of architectures for the semiconductor supports to promote the selective activity of specific crystallographic facets. The search for efficient heterojunctions has been subjected to numerous studies, especially those involving gold nanostructures and titania semiconductors. In the present review, we paid special attention to the most recent advances in the design of gold-semiconductor hetero-nanostructures including emerging metal oxides such as cerium oxide or copper oxide (CeO2 or Cu2O) or metal chalcogenides such as copper sulfide or cadmium sulfides (CuS or CdS). These alternative hybrid materials were thoroughly built in past years to target research fields of strong impact, such as solar energy conversion, water splitting, environmental chemistry, or nanomedicine. Herein, we evaluate the influence of tuning the morphologies of the plasmonic gold nanostructures or the semiconductor interacting structures, and how these variations in geometry, either individual or combined, have a significant influence on the final photocatalytic performance.

This work describes the synthesis of nitrogen‐doped carbon nanodots (CNDs) synthesized from ethylenediaminetetraacetic acid (EDTA) as a precursor and their application as luminescent agents with a dual‐mode theranostic role as near‐infrared (NIR) triggered imaging and photodynamic therapy agents. Interestingly, these fluorescent CNDs are more rapidly and selectively internalized by tumor cells and exhibit very limited cytotoxicity until remotely activated with a NIR illumination source. These CNDs are excellent candidates for phototheranostic purposes, for example, simultaneous imaging and therapy can be carried out on cancer cells by using their luminescent properties and the in situ generation of reactive oxidative species (ROS) upon excitation in the NIR range. In the presence of CNDs, NIR remote activation induces the in vitro killing of U251MG cells. Through the use of flow imaging cytometry, we have been able to successfully map and quantify the different types of cell deaths induced by the presence of intracellular superoxide anions (.O2−) and hydrogen peroxide (H2O2) ROS generated in situ upon NIR irradiation., The authors acknowledge the European Research Council for funding through an advanced grant research project (HECTOR grant number 267626; CADENCE grant number 742684) and a CIG‐Marie Curie Reintegration Grant (NANOLIGHT REA grant number 294094). M.C.O. acknowledges the Spanish Government for a FPU predoctoral fellowship.

The present work investigates the role of two types of carbon nanodots (CNDs) as novel sensitizers of TiO2 to create a visible-light driven photo-catalyst that is not only efficient for solar-driven pollution abatement, but also inexpensive, durable and environmentally-friendly. Two widely available green organic precursors, the Argentinean herb Mate and the Stevia plant have been selected as the carbogenic source to thermally induce the formation of different types of CNDs with different levels of N and P doping and tunable photoluminescence response in the UV–vis-near infrared (NIR) ranges. These CNDs have been successfully assembled with TiO2 to form heterogeneous photocatalysts that are highly active in the visible-light and NIR- driven photodegradation of 2,4-dichlorophenol (2,4-DCP), a persistent chlorinated organic compound present in numerous pesticide formulations.

The shape and porous configuration of supports are key parameters to design outstanding catalysts. However, the selection of a proper mesoporous support, such as SBA-15, by itself does not guarantee accessibility to catalytic sites. The distribution of the active phase and its stability are strongly related to the procedure used to deposit it on the catalytic substrate. Herein, we have prepared rod-shaped SBA-15 silica supports functionalized with amine groups to facilitate the electrostatic attraction and a good distribution of the resulting Pt-based catalytic nanoparticles along the pore walls. Additionally, the use of tetrakis-(hydroxymethyl)-phosphonium chloride (THPC) as both reductant and stabilizer is presented as a novel alternative for Pt nanoparticle synthesis. The behaviour of this catalyst in the total oxidation of n-hexane demonstrates high activity and excellent stability after 70 h on reaction stream. STEM-HAADF and 3-D tomography were used to confirm the presence of the metallic nanoparticles within the mesochannels and to corroborate their reduced sintering after reaction.

Although several methods on the preparation of carbon nanodots (CNDs) emitting throughout the visible have been recently reported, in most of the processes the product suffers from inhomogeneity in size and shape limiting their impact. Here, we report the synthesis of undoped and nitrogen-doped luminescent carbon nanodots by rapid pyrolysis using ordered mesoporous silica nanorods as confining templates. A rapid thermal decomposition (pyrolysis) within the confined dimensions of their pores leads to a highly uniform size distribution of CNDs with average sizes below 4 nm. These CNDs are synthesized in an extremely short time period (5 min of reaction) by immersion in a fluidized-bed reactor that provides heating homogeneity and ensures fast heat transfer. In addition, a rapid release of the homogeneous CNDs can be easily achieved by a simple ultrasonication-filtration step that prevents further chemical action on the mesoporous templates. The emission of both undoped and N-doped CNDs in colloidal and solid state (with an efficiency of 1–5%) originates from a combination of quantum confinement effects and the presence of oxidized surface states; N-doping introduces resonant absorption states which participate in emission. Furthermore, we present a simple model to describe the excitation-dependent/-independent mechanism of carbon nanodots.

In this work we present a novel metal-semiconductor heterostructure that contains triangular and prism-shaped plasmonic gold nanostructures directly synthesized and assembled onto ZnO nanostructures. Spatially-resolved (SR) high-resolution electron energy loss spectroscopy (EELS) at the local (sub-nanometer scale) level confirmed the field enhancement of the local electromagnetic fields in the surroundings of the triangular and prism-shaped Au nanostructures and in the interfacial junction between Au and ZnO. Different LED excitation sources have been systematically selected in the whole UV–vis-NIR range to evaluate the photocatalytic response of the Au-ZnO heterostructures towards the oxidation of n-hexane, selected as a model VOC present in indoor environments. The Au-ZnO exhibits visible expanded photo-response with the more energetic interband and intraband electrons and the higher LED irradiation wavelengths and it is able to outperform its ZnO plain counterpart., Financial support from the European Research Council (ERC Advanced Grant CADENCE number 742684) is gratefully acknowledged. We also acknowledge the support from CIBER-BBN and MINECO (Spain) with project CTQ2016-79419-R. R.A. acknowledges funding from the Spanish Ministerio de Ciencia, Innovación y Universidades (project grant MAT2016-79776-P (AEI/FEDER, UE)) and from the European Union H2020 program “ESTEEM3” (823717).

Microwave (MW) heating has been applied to increase the selectivity to propylene in the oxidative dehydrogenation (ODH) of propane. The preferential heating of the solid monolith (made of SiC, a good microwave susceptor), allows working with a lower gas phase temperature, reducing the formation of undesired by-products in the gas phase via homogeneous reactions. Conversion levels of ~ 21% and selectivity to propylene up to 70% have been achieved with MW-heated straight channel monolithic reactors coated with a VMgO catalyst. These competitive values contrast with the more limited performance delivered by the same catalytic system when it is subjected to conventional heating in a fixed-bed reactor configuration, thereby corroborating the advantage of working under a significant gas–solid temperature gap to minimize the extent of homogeneous reactions., Financial support from the European Research Council (ERC Advanced Grant HECTOR-267626) and the Regional Government of Aragon (DGA) is gratefully acknowledged. The CIBER-BBN (initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund) is gratefully acknowledged.

Natural gas is currently envisioned as a potential energy and hydrocarbon feedstock in the forthcoming years. To overcome the detrimental flaring of this natural gas and the partial release of its major component, methane, novel and more effective strategies are required. These include the development of new, efficient and seemingly stable catalysts able to rapidly convert methane into valuable feedstocks. We show a novel synthesis method of Mo/ZSM-5 based on a solvothermal synthesis under supercritical conditions and reducing atmosphere (SC-STS-E) to improve metal dispersion and enhance catalyst stability and durability during the methane dehydroaromatization (MDA) reaction. In contrast to the conventional impregnation method, SC-STS-E provides a super-high atom-like metal dispersion at the zeolite pores resulting in the most stable Mo/ZSM-5 catalyst for MDA with the highest long-term hydrocarbon yield (xCH4 = 11.6% and yC2+ = 8.9%, after 15 h on stream) among the catalysts reported in literature for this reaction., Financial support from the European Union’s Horizon 2020 Research and Innovation Programme (ADREM project – Grant Agreement No. 680777) is gratefully acknowledged.

This article belongs to the Special Issue Microwave-Assisted Catalysis., Microwave-assisted heterogeneous catalysis (MHC) is gaining attention due to its exciting prospects related to selective catalyst heating, enhanced energy-efficiency, and partial inhibition of detrimental side gas-phase reactions. The induced temperature difference between the catalyst and the comparatively colder surrounding reactive atmosphere is pointed as the main factor of the process selectivity enhancement towards the products of interest in a number of hydrocarbon conversion processes. However, MHC is traditionally restricted to catalytic reactions in the absence of catalyst coking. As excellent MW-susceptors, carbon deposits represent an enormous drawback of the MHC technology, being main responsible of long-term process malfunctions. This work addresses the potentials and limitations of MHC for such processes affected by coking (MHCC). It also intends to evaluate the use of different catalyst and reactor configurations to overcome heating stability problems derived from the undesired coke deposits. The concept of long-term MHCC operation has been experimentally tested/applied to for the methane non-oxidative coupling reaction at 700 °C on Mo/ZSM-5@SiC structured catalysts. Preliminary process scalability tests suggest that a 6-fold power input increases the processing of methane flow by 150 times under the same controlled temperature and spatial velocity conditions. This finding paves the way for the implementation of high-capacity MHCC processes at up-scaled facilities., This research was funded by the European Union’s Horizon 2020 Research and Innovation Programme (ADREM project–Grant Agreement no. 680777) and the APC have been waived by the journal.

Cesium lead halide perovskite nanocrystals are being lately explored for optoelectronic applications due to their emission tunability, high photoluminescence quantum yields, and narrow emission bands.Nevertheless, their incompatibility with polar solvents and composition homogenization driven by a fast anion-exchange are still important drawbacks to overcome. Herein we report on a successful encapsulation of colloidal perovskite nanocrystals within solid–lipid structures mainly consisting of stearic acid. The product is water-stable for a period longer than 2 months and anion-exchange is fully arrested when mixing nanocrystals of different halide compositions. This strategy boosts the potential applications of all-inorganicperovskite nanocrystals for ink-printing.

Water-soluble, biocompatible, and photoluminescent carbon nanodots have been obtained from the rationalized carbonization of vitamin C, a well-known antioxidant molecule in the presence of an amine co-reactant. Herein, we describe the positive influence of N-doping to induce a unique pH-dependent lifetime decay response that would be potentially attractive in biological backgrounds with intrinsic fluorescence fluctuations. In addition, the selectivity and sensitivity of the N-containing carbon nanoprobes towards the detection of copper ions at ppm levels is critically enhanced in comparison with the un-doped counterpart, especially in the near-infrared (NIR) range. Finally, the up-converting properties have been also successfully applied to image tumor cells in the visible range and remarkably, in the NIR region in which minimal tissue or water absorption and maximum penetration depth are expected.

The selective oxidation of ethylene to ethylene epoxide is highly challenging as a result of competing reaction pathways leading to the deep oxidation of both ethylene and ethylene oxide. Herein we present a novel catalyst based on silver and copper oxide with an excellent response in the selective oxidation pathway towards ethylene epoxide. The catalyst is composed of different silver nanostructures dispersed on a tubular copper oxide matrix. This type of hybrid nanoarchitecture seems to facilitate the accommodation of chlorine promoters, leading to high yields at low reaction temperatures. The stability after the addition of chlorine promoters implies a substantial improvement over the industrial practice: a single pretreatment step at ambient pressure suffices in contrast with the common practice of continuously feeding organochlorinated precursors during the reaction.

Luminescent carbon nanodots (CNDs) have been obtained by hydrothermal processing of ascorbic acid (AA) and ethanolamine (EN). The resulting N-doped carbon nanostructures exhibit interesting and tunable emission capabilities with a dual behavior as down-converters and more importantly, as up-converting quantum dots. Herein, we also evaluate the optical response of these CNDs to selectively generate highly reactive oxidative hydroxyls ( OH) upon irradiation with different light-emitting diodes (LEDs) in the visible–NIR range. Finally, the role of the N-doped CNDs as nano-sensitizers to maximize the solar light harvesting and expand the photo-catalytic response of a commonly used UV-active catalyst such as TiO2 was successfully tested in the degradation of an organo-chlorinated compound under visible light.

Gold‐based nanocatalysts have been traditionally selected for multiple homogeneous and heterogeneous reactions of interest involving redox processes. Likewise, greener routes involving more efficient reactors and the use of inexpensive and nature‐mimicking excitation sources have boosted the research on photocatalysts that can drive these chemical reactions upon excitation with multiple wavelength sources beyond the UV range. In the present work we report on a multi‐step synthesis approach that enables the in situ generation of triangular and prism‐shaped gold nanostructures with a localized surface plasmon resonance effect and their direct assembly onto a ZnO nanostructured semiconductor support. Different LED excitation sources in the whole UV/Vis‐NIR range have been systematically selected to activate these hybrid materials in the selective reduction of p‐nitrophenol (4‐NP), a well‐known contaminant by‐product. While ZnO becomes preferentially active in the UV window, the anisotropic shape of these gold plasmonic nanostructures helps to broaden the photocatalytic response of ZnO towards the visible and NIR range, being especially active under 460 nm blue light irradiation and expanding their potential application in multiple solar‐driven catalytic processes of interest for decontamination and upgrading of toxic chemicals., The authors acknowledge the European Research Council for funding through an Advanced Grant research project (CADENCE grant number 742684). Financial support from MINECO (Spain) (ARCADIA‐CTQ2016‐79419‐R) and the CIBER‐BBN (initiative funded by the VI National R&D&i Plan 2008‐2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund) is gratefully acknowledged. B. B. ‐P. acknowledges the University of Zaragoza and Fundacion Carolina for funding his MSc. studies.

Research in solid-gas heterogeneous catalytic processes is typically aimed toward optimization of catalyst composition to achieve a higher conversion and, especially, a higher selectivity. However, even with the most selective catalysts, an upper limit is found: Above a certain temperature, gas-phase reactions become important and their effects cannot be neglected. Here, we apply a microwave field to a catalyst-support ensemble capable of direct microwave heating (MWH). We have taken extra precautions to ensure that (i) the solid phase is free from significant hot spots and (ii) an accurate estimation of both solid and gas temperatures is obtained. MWH allows operating with a catalyst that is significantly hotter than the surrounding gas, achieving a high conversion on the catalyst while reducing undesired homogeneous reactions. We demonstrate the concept with the CO 2 -mediated oxidative dehydrogenation of isobutane, but it can be applied to any system with significant undesired homogeneous contributions., Financial support from the European Research Council Advanced Grant (HECTOR267626), the Regional Government of Aragon (DGA), and the MINECO and FEDER (project CTQ2015-65226) is acknowledged.

This work presents a highly efficient photo-reactor configuration for VOC abatement. It consists of a fluidized bed made of commercial, easy to fluidize, transparent borosilicate glass beads coated with commercial TiO2 nanoparticles (0.15–2.3 wt% loadings). Herein, we demonstrate that the use of high-radiance/low consumption UV-LEDs as irradiation sources with a deeper light penetration under fluidizing conditions facilitates the photocatalytic response to achieve the complete oxidation of VOCs. The role of different parameters such as catalyst loading and irradiation power have been thoroughly studied and evaluated to maximize the full combustion of n-hexane. Under the high radiance (up to 2200 mW/cm2) conditions used the bed heats significantly (up to 190 °C), although this did not have an effect on the conversions reached, which depended solely on the wavelength and power used. The productivity of the photoreactor tested and the space velocity used were around 5.25 × 10−2 mol/g·h and 12000 h−1 respectively., Financial support from MINECO (Spain) with projects CTQ2016-77147-R and CTQ2016-79419-R and the CIBER-BBN is gratefully acknowledged. We also acknowledge the support from HECTOR project.

In Press., Methane can be obtained from the direct hydrogenation of CO2 via the Sabatier reaction. This reaction is usually performed at high temperatures and/or pressures but it has been recently reported that in the presence of certain nanostructured catalysts, CO2 methanation can proceed at lower temperatures in solar photo-assisted processes. In this study, an inexpensive and commercially available nickel-based catalyst (Ni/Al2O3·SiO2) has been selected to perform the continuous CO2 hydrogenation in a fixed bed photocatalytic reactor using high-radiance/low consumption light emitting diodes (LEDs). These illumination conditions allowed us to attain the reaction temperatures required without the need of additional heating sources. Different LED excitation wavelengths and irradiances were evaluated. Under selected irradiation conditions (460 nm wavelength) not only the photothermal but also the photo-catalytic conversion of CO2 into CH4 takes place, with high selectivity. Conversion levels above 70% with production rates of ca. 35 mmol CH4 g−1 h-1 were obtained, outperforming the results obtained by conventional heating methods or with other irradiation wavelengths., Financial support from MINECO (Spain) (ARCADIA-CTQ2016-79419-R) and the CIBER-BBN (initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund) is gratefully acknowledged. The synthesis of materials has been performed at the facilities of the NANOBIOSIS ICTS, managed by the Nanoparticle Synthesis Unit of the CIBER-BBN. The microscopy works have been conducted in the "Laboratorio de Microscopias Avanzadas" at "Instituto de Nanociencia de Aragon - Universidad de Zaragoza. Dr. Irusta is gratefully acknowledged for performing the XPS analysis. A.A.R. thanks the Spanish Government for a Juan de la Cierva postdoctoral fellowship.

This article belongs to the Special Issue Advanced Photocatalytic Materials., Volatile organic compounds (VOCs) are recognized as hazardous contributors to air pollution, precursors of multiple secondary byproducts, troposphere aerosols, and recognized contributors to respiratory and cancer-related issues in highly populated areas. Moreover, VOCs present in indoor environments represent a challenging issue that need to be addressed due to its increasing presence in nowadays society. Catalytic oxidation by noble metals represents the most effective but costly solution. The use of photocatalytic oxidation has become one of the most explored alternatives given the green and sustainable advantages of using solar light or low-consumption light emitting devices. Herein, we have tried to address the shortcomings of the most studied photocatalytic systems based on titania (TiO2) with limited response in the UV-range or alternatively the high recombination rates detected in other transition metal-based oxide systems. We have developed a silver-copper oxide heteronanostructure able to combine the plasmonic-enhanced properties of Ag nanostructures with the visible-light driven photoresponse of CuO nanoarchitectures. The entangled Ag-CuO heteronanostructure exhibits a broad absorption towards the visible-near infrared (NIR) range and achieves total photo-oxidation of n-hexane under irradiation with different light-emitting diodes (LEDs) specific wavelengths at temperatures below 180 °C and outperforming its thermal catalytic response or its silver-free CuO illuminated counterpart., This research was funded by ARCADIA (grant CTQ2016-77147) and CADENCE (grant 742684) and the APC was waived by the journal.

The conversion of methane into higher molecular weight hydrocarbons of greater added value has emerged as one of the grand challenges of the 21st century. The non-oxidative methane dehydroaromatization (hereafter MDA) reaction is a promising methane valorisation reaction since it transforms methane into added-value aromatics and olefins, namely benzene, naphthalene and ethylene. Molybdenum-promoted ZSM-5 zeolite has proven to be one of the most effective catalysts for MDA providing a shape-selective environment for the conversion of methane into benzene. However, one of the principle disadvantages of using aluminosilicates in the presence of methane is that the catalyst suffers from rapid deactivation induced by coke formation, which ultimately leads to a decrease in activity and aromatics selectivity, making the process unsuitable for large-scale industrial applications. Better control of the metal dispersion on the surface of the aluminosilicate supports represents a crucial factor to partially suppress catalyst coking and improve stability. Here we show how different molecular polyoxomolybdate (POM) anions can be used as alternative Mo precursors to conventional Mo salts for the preparation of catalysts for the MDA reaction. Molecular dynamics simulations and experimental testing were conducted to characterize the interphase interactions between polyoxomolybdates and zeolite surfaces at the atomistic level and to evaluate the MDA performance of different POM-based catalysts supported on ZSM-5 and MCM-22, respectively. The catalysts prepared using hexamolybdate anions, [Mo6O19]2−, were found to be more active and selective towards benzene than those employing the commercial heptamolybdate, [Mo7O24]6−. The Mo loading and dispersion of MoOx species were found to be the key factors leading to enhanced catalytic stability on ZSM-5 and MCM-22-based supports for MDA where the 5% Mo6/MCM-22 catalyst provided a constant aromatics yield above 7% for more than 18 hours time-on stream operating at 700 °C with a diluted methane flow under atmospheric pressure. The zeolitic catalysts prepared with the Mo6 precursor were found to be amongst the most promising MDA catalysts in the literature and the results of this study pave the way for the selection and use of different POMs as innovative metal precursors to formulate new catalysts and further improve the MDA reaction process., Financial support from the European Union's Horizon 2020 Research and Innovation Programme (ADREM project – Grant Agreement No. 680777) is gratefully acknowledged. The microscopy measurements were conducted at the Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Spain. The synthesis of the materials has been performed at the Platform of Production of Biomaterials and Nanoparticles of the NANOBIOSIS ICTS, more specifically at the Nanoparticle Synthesis Unit of the CIBER in BioEngineering, Biomaterials & Nanomedicine (CIBER-BBN). JMP thanks the Spanish Ministry of Science (CTQ2017-87269-P), the Generalitat de Catalunya (2017SGR629) and the URV for support. JMP also thanks the ICREA foundation for an ICREA ACADEMIA award.

One-step synthesis of luminescent mesoporous rods with enhanced photocatalytic response as novel metal-free peroxidase-like nanozymes., Herein we report on a novel inorganic peroxidase-mimicking nanocatalyst activated under blue LED photoirradiation. A novel flash-pyrolysis method has been developed for the generation of strong blue photoluminescence (PL) centers attributed to silicon and carbon-based sites within a mesoporous SBA-15 silica nanorod platform. The type of centers and their PL response can be controlled by varying the flash thermal treatment conditions. By tailoring the operating conditions the system can be driven towards the preferential generation of carbon-based luminescent centers, with or without the simultaneous generation of silicon-based centers. The properties and the nature of these luminescent centers within the mesoporous nanorods have been thoroughly corroborated by a battery of characterization techniques including fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS) at the local level of the structures combined with scanning transmission electron microscopy (STEM) imaging. In addition, these luminescent mesoporous nanorods have been successfully tested as robust photocatalysts able to display peroxidase-like activity and indirect glucose sensing in a wider range of pH conditions compared to the natural enzyme, especially when carbogenic dots and oxygen-deficient silica centers are simultaneously present in the structure.

The present work combines the use of microfluidic reactors and green chemicals such as glucose and starch to achieve a continuous production of silver nanoparticles that have been successfully tested as excellent antibacterial agents against Escherichia coli. Those silver nanoparticles synthesized under continuous flow remained stable in terms of optical response, morphology and size distribution even after 48 months of storage at 24 °C without light protection. The best results in terms of colloidal stability were obtained after synthesizing those nanoparticles at 70 C in the presence of an excess of glucose when the continuous flow configuration was used to complete the reaction within 9 min. In contrast, analogous experiments carried out in batch conditions required a much longer period to achieve similar results but with much lower stability and a higher polydispersity, especially in the long-term storage range. Fil: Giorello, Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Gioria, Esteban Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Hueso, Jose L.. Nanoscience Institute Of Aragon (ina); . Ciber Bioingenieria, Biomateriales y Nanomedicina; Fil: Sebastian, Victor. Ciber Bioingenieria, Biomateriales y Nanomedicina; . Nanoscience Institute Of Aragon (ina); Fil: Arruebo, Manuel. Ciber Bioingenieria, Biomateriales y Nanomedicina; . Nanoscience Institute Of Aragon (ina); Fil: Veaute, Carolina Melania Isabel. Universidad Nacional del Litoral; Argentina Fil: Gutierrez, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina

This article belongs to the Special Issue Recent Advances on Carbon and Noble-Metal Based Photocatalysts., In this work, we present photocatalysis as a greener alternative to conventional catalysis where harsh reaction conditions, temperature and/or pressure are needed. Photodegradation of organic pollutants is a cost-effective, eco-friendly solution for the decontamination of water and air, and is a field that has been continuously growing over the last decade. Plasmonic metal nanoparticles absorb light irradiation that is transferred to the chemical reaction in a different fashion. Furthermore, plasmonic nanostructures can be combined with other materials, such as semiconductors or a basic support, to create hybrid systems capable of overcoming certain challenges that photocatalysis is facing nowadays and to expand the photocatalytic response towards the whole visible-near infrared (Vis-NIR) ranges. The main objective of this work has been to in-situ synthesize plasmonic anisotropic gold nanoparticles onto hydrotalcite (HT) and calcined hydrotalcite (CHT) supports by way of a sequential deposition-reduction (DR) process and to evaluate their efficiency as heterogeneous catalysts towards the selective oxidation of p-nitrophenol (hereafter 4-NP), a well-known model contaminant, either in the absence or the presence of full-range light irradiation sources (LEDs) spanning the whole UV-Vis-NIR range. Special attention has been paid to the optimization of the catalyst preparation parameters, including the pH and the concentration of reducing and stabilizing agents. Interestingly, the use of thermally modified hydrotalcites has enabled a strong metal-support interaction to induce the preferential formation of triangular-shaped Au nanoparticles with ca. 0.8 wt.% loading while increasing the colloidal stability and surface area of the catalyst with respect to the commercial untreated HT supports., This research was funded by ARCADIA (grant CTQ2016-77147) and CADENCE (grant 742684) and the APC was waived by the Editorial Team of Catalysts.

The use of tetrakis-(hydroxymethyl)-phosphonium chloride (THPC) as simultaneous reducing agent and stabilizing ligand has been extended to the single-step synthesis at room temperature of a wide variety of monometallic nanoparticles and bi-/tri- metallic nanoalloys containing noble metals with potential application in catalysis. The colloidal suspensions exhibit mean diameters below 4 nm with narrow size distributions and high stability in aqueous solution for long periods of time.

Infrared thermographic techniques have been used for the first time to determine real-time gas and solid temperatures, as well as gas-solid temperature gradients in microwave heated structured reactors. A special reactor vessel has been developed that allows direct observation of the catalyst under microwave heating, and an operating procedure is presented to obtain gas and solid apparent emissivities as a function of temperature. These values are thereafter used to calculate temperatures at any point in the gas and solid phases under reaction. The method has been used to obtain gas and solid temperatures during the ethylene epoxidation reaction carried out on a silver-copper oxide catalyst. The direct heating of the monolith walls produced a stable, large temperature gradient between the solid and the gas phase.

The main problem to be addressed in the valorization of methane under non-oxidative conditions (MNOC) is to reduce or even avoid coke formation. In this work we report the use of microwave-assisted heating for MNOC. We have developed a system able to heat-up a Mo-ZSM5 catalyst coated on silicon carbide monolith that could operate stable for at least 19 h at reaction conditions, 700 °C. We demonstrate that under MW-heating the selectivity shifts to C2s and benzene. In contrast, the operation under conventional heating (CH) produces more coke and polyaromatics. The selective microwave heating has two effects in this reaction: i) during the activation of the catalyst the formation of the active catalytic species of Mo2C inside the microporous support is different affecting the selectivity and product distribution; ii) a gas-solid temperature gradient is established that prevents the formation of coke from PAHs in the gas phase. The MNOC process under controlled MW heating at high space velocity (3000 mL/gcat·h) gives a hydrocarbon yield of around 6% with a very low deactivation rate. These results open up new possibilities for process intensification using alternative sources of energy, as is the case of microwaves, for heating structured catalytic reactors.

In this work we investigate the formation of PtAu monodisperse alloyed nanoparticles by ageing pure metallic Au and Pt small nanoparticles (sNPs), nanoparticle size

We demonstrate the enhanced photocatalytic response of a novel Fenton-like heterogeneous catalyst obtained through the assembly of superparamagnetic feroxyhyte nanoflakes synthesized by continuous gas-slug microfluidics and carbon nanodots obtained by pyrolysis from a natural organic source. The novel nanohybrids enable the utilization of the visible and near-infrared ranges due to the active role of the carbon nanodots as up-converting photo-sensitizers. This novel photocatalyst is magnetically recoverable and maintains an excellent response after multiple reutilization cycles. In addition, its synthesis is based on inexpensive and abundant raw materials and its photocatalytic response is evaluated in the presence of energy efficient, affordable light-emitting diodes (LEDs), thereby providing a promising and feasible alternative to the homogeneous Fenton process.

The present work shows an efficient strategy to assemble two types of functional nanoparticles onto mesoporous MCM-41 silica nanospheres with a high degree of spatial precision. In a first stage, magnetite nanoparticles are synthesized with a size larger than the support pores and grafted covalently through a peptide-like bonding onto their external surface. This endowed the silica nanoparticles with a strong superparamagnetic response, while preserving the highly ordered interior space for the encapsulation of other functional guest species. Second, we report the finely controlled pumping of preformed Pt nanoparticles (1.5 nm) within the channels of the magnetic MCM-41 nanospheres to confer an additional catalytic functionality to the multiassembled nanoplatform. The penetration depth of the metallic nanoparticles can be explained as a result of the interplay between the particle-wall electrostatic attraction and the repulsive forces between neighboring Pt nanoparticles. A detailed transmission electron microscopy and a 3D high-resolution high-angle annular dark-field detector electron tomography study were carried out to characterize the material and to explain the assembly mechanism. Finally, the performance of these multifunctional nanohybrids as magnetically recoverable catalysts has been evaluated in the selective hydrogenation of p-nitrophenol, a well-known pollutant and intermediate in multiple industrial processes.