Amine-Functionalized Titanate Nanosheet-Assembled Yolk@Shell Microspheres for Efficient Cocatalyst-Free Visible-Light Photocatalytic CO2 Reduction

Density Matching for Microencapsulation of Field Responsive Suspensions of Non-Brownian Microparticles

When forming composite microcapsules through the emulsification of a dispersed phase laden with microparticles, one will find that the microparticles become irreversibly embedded in the resulting microcapsule membrane. This phenomenon, known as Pickering stabilization, is detrimental when the end function of the microcapsules relies on the mobility of encapsulated microparticles within the capsule core. In this work, a robust microencapsulation route using density matching of non-Brownian microparticles in a binary solvent is shown to easily and effectively encapsulate particles, with >90% of particles retaining mobility within the microcapsules, without the necessity for prior chemical/physical modifications to the microparticles. This is proposed as a generalized method to be used for all manner of particle chemistries, shapes, and sizes.

Effect of stabilizer content in different solvents on the synthesis of ZnO nanoparticles using the chemical precipitation method

Zinc Oxide (ZnO) nanoparticles (NPs) have been synthesized by a simple chemical precipitation method. The effect of monoethanolamine (MEA) content in different solvents on ZnO NPs synthesis and their structural properties has been investigated. The NPs synthesized by using isopropanol (IPA) with 15 ml MEA as a stabilizer under the most favorable conditions (deposition time, td = 120 min, temperature = 60 °C) showed good structural properties. Synthesized NPs exhibited beneficial structural properties after annealing. The hexagonal wurtzite crystal structure of ZnO NPs was verified by XRD. Different models were used to calculate structural parameters such as crystallite size, strain, stress, and energy density for all the reflection peaks of XRD corresponding to ZnO lying in the range 2θ = 15⁰-80⁰. The crystallite size of the ZnO nanoparticles was found to be 50-60 nm. FTIR and EDX confirmed the presence of ZnO NPs in the samples. SEM micrograph of all the samples revealed that the grain sizes decrease gradually with the increase of the amount of MEA. UV-Visible diffuse reflectance spectroscopy results provide evidence that the ZnO NPs possess broader absorption bands, together with high band gap energy. The ZnO NPs synthesized with IPA solvent have the highest transmittance and band gap energy of 3.3eV. According to DLS data, various content of MEA stabilizer in solvent affects the hydrodynamic size of ZnO NPs.

Hierarchical Hollow-TiO2@CdS/ZnS Hybrid for Solar-Driven CO2-Selective Conversion

Light-driven valorization conversion of CO₂ is an encouraging carbon-negative pathway that shifts energy-reliance from fossil fuels to renewables. Herein, a hierarchical urchin-like hollow-TiO₂@CdS/ZnS (HTO@CdS/ZnS) Z-scheme hybrid synthesized by an in situ self-assembly strategy presents superior photocatalytic CO₂-to-CO activity with nearly 100% selectivity. Specifically, benefitting from the reasonable architectural and interface design, as well as surface modification, this benchmarked visible-light-driven photocatalyst achieves a CO output of 62.2 μmol·h^-1 and a record apparent quantum yield of 6.54% with the Co(bpy)₃²⁺ (bpy = 2,2'-bipyridine) cocatalyst. It rivals all the incumbent selective photocatalytic conversion of CO₂ to CO in the CH₃CN/H₂O/TEOA reaction systems. Specifically, the addition of HTO and stabilized ZnS enables the photocatalyst to effectively upgrade optical and electrical performances, contributing to efficient light-harvesting and photogenerated carrier separation, as well as interfacial charge transfer. The tremendous enhancement of photocatalytic performance reveals the superiority of the Z-scheme heterojunction assembled from HTO and CdS/ZnS, featuring the inner electric field derived from the band bending of HTO@CdS/ZnS make CdS resistant to photocorrosion. This study allows access to inspire studies on rationally modeling and constructing diverse heterostructures for the storage and conversion of renewables and chemicals.

Recent Advances and Perspectives of Core-Shell Nanostructured Materials for Photocatalytic CO2 Reduction

Photocatalytic CO₂ conversion into solar fuels is a promising technology to alleviate CO₂ emissions and energy crises. The development of core-shell structured photocatalysts brings many benefits to the photocatalytic CO₂ reduction process, such as high conversion efficiency, sufficient product selectivity, and endurable catalyst stability. Core-shell nanostructured materials with excellent physicochemical features take an irreplaceable position in the field of photocatalytic CO₂ reduction. In this review, the recent development of core-shell materials applied for photocatalytic reduction of CO_{2 is introduced} . First, the basic principle of photocatalytic CO₂ reduction is introduced. In detail, the classification and synthesis techniques of core-shell catalysts are discussed. Furthermore, it is also emphasized that the excellent properties of the core-shell structure can greatly improve the activity, selectivity, and stability in the process of photocatalytic CO₂ reduction. Hopefully, this paper can provide a favorable reference for the preparation of efficient photocatalysts for CO₂ reduction.

A Comprehensive Review on Graphitic Carbon Nitride for Carbon Dioxide Photoreduction

Inspired by natural photosynthesis, harnessing the wide range of natural solar energy and utilizing appropriate semiconductor-based catalysts to convert carbon dioxide into beneficial energy species, for example, CO, CH₄ , HCOOH, and CH₃ COH have been shown to be a sustainable and more environmentally friendly approach. Graphitic carbon nitride (g-C₃ N₄ ) has been regarded as a highly effective photocatalyst for the CO₂ reduction reaction, owing to its cost-effectiveness, high thermal and chemical stability, visible light absorption capability, and low toxicity. However, weaker electrical conductivity, fast recombination rate, smaller visible light absorption window, and reduced surface area make this catalytic material unsuitable for commercial photocatalytic applications. Therefore, certain procedures, including elemental doping, structural modulation, functional group adjustment of g-C₃ N₄ , the addition of metal complex motif, and others, may be used to improve its photocatalytic activity towards effective CO₂ reduction. This review has investigated the scientific community's perspectives on synthetic pathways and material optimization approaches used to increase the selectivity and efficiency of the g-C₃ N₄ -based hybrid structures, as well as their benefits and drawbacks on photocatalytic CO₂ reduction. Finally, the review concludes a comparative discussion and presents a promising picture of the future scope of the improvements.

Cu Nanoparticles Modified Step-Scheme Cu2O/WO3 Heterojunction Nanoflakes for Visible-Light-Driven Conversion of CO2 to CH4

In this study, Cu and Cu2O hybrid nanoparticles were synthesized onto the WO3 nanoflake film using a one-step electrodeposition method. The critical advance is the use of a heterojunction consisting of WO3 flakes and Cu2O as an innovative stack design, thereby achieving excellent performance for CO2 photoreduction with water vapor under visible light irradiation. Notably, with the modified Cu nanoparticles, the selectivity of CH4 increased from nearly 0% to 96.7%, while that of CO fell down from 94.5% to 0%. The yields of CH4, H2 and O2 reached 2.43, 0.32 and 3.45 mmol/gcat after 24 h of visible light irradiation, respectively. The boosted photocatalytic performance primarily originated from effective charge-transfer in the heterojunction and acceleration of electron-proton transfer in the presence of Cu nanoparticles. The S-scheme charge transfer mode was further proposed by the in situ-XPS measurement. In this regard, the heterojunction construction showed great significance in the design of efficient catalysts for CO2 photoreduction application.

Enabling High Loading in Single-Atom Catalysts on Bare Substrate with Chemical Scissors by Saturating the Anchoring Sites

Atomically dispersed metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low to avoid the formation of metal nanoparticles, making it difficult to improve the overall activity. Diverse strategies based on creating more anchoring sites (ASs) have been adopted to elevate the loading density. One problem of such traditional methods is that the single atoms always gather together before the saturation of all ASs. Here, a chemical scissors strategy is developed by selectively removing unwanted metallic materials after excessive loading. Different from traditional ways, the chemical scissors strategy places more emphasis on the accurate matching between the strength of etching agent and the bond energies of metal-metal/metal-substrate, thus enabling a higher loading up to 2.02 wt% even on bare substrate without any pre-treatment (the bare substrate without any pre-treatment generally only has a few ASs for single atom loading). It can be inferred that by combining with other traditional methods which can create more ASs, the loading could be further increased by saturating ASs. When used for CH₃ OH generation via photocatalytic CO₂ reduction, the as-made single-atom catalyst exhibits impressive catalytic activity of 597.8 ± 144.6 µmol h^-1 g^-1 and selectivity of 81.3 ± 3.8%.

Integrated catalytic insights into methanol production: Sustainable framework for CO2 conversion

A continuous increase in the amount of greenhouse gases (GHGs) is causing serious threats to the environment and life on the earth, and CO₂ is one of the major candidates. Reducing the excess CO₂ by converting into industrial products could be beneficial for the environment and also boost up industrial growth. In particular, the conversion of CO₂ into methanol is very beneficial as it is cheaper to produce from biomass, less inflammable, and advantageous to many industries. Application of various plants, algae, and microbial enzymes to recycle the CO₂ and using these enzymes separately along with CO₂-phillic materials and chemicals can be a sustainable solution to reduce the global carbon footprint. Materials such as MOFs, porphyrins, and nanomaterials are also used widely for CO₂ absorption and conversion into methanol. Thus, a combination of enzymes and materials which convert the CO₂ into methanol could energize the CO₂ utilization. The CO₂ to methanol conversion utilizes carbon better than the conventional syngas and the reaction yields fewer by-products. The methanol produced can further be utilized as a clean-burning fuel, in pharmaceuticals, automobiles and as a general solvent in various industries etc. This makes methanol an ideal fuel in comparison to the conventional petroleum-based ones and it is advantageous for a safer and cleaner environment. In this review article, various aspects of the circular economy with the present scenario of environmental crisis will also be considered for large-scale sustainable biorefinery of methanol production from atmospheric CO₂.

Directing photocatalytic pathway to exceedingly high antibacterial activity in water by functionalizing holey ultrathin nanosheets of graphitic carbon nitride

Metal-free polymeric carbon nitride (C₃N₄) photocatalysts offer attractive technological advantages over the conventional transition metal oxides or sulfides -based photocatalysts in water disinfection, but their antimicrobial activities are limited by their rapid charge carrier recombination and low specific surface areas. By controlling photocatalytic pathways, we obtained in amino-rich holey ultrathin g-C₃N₄ nanosheets (AHUCN) a highly efficient inactivation rate against E-coli, which is the highest among the monolithic g-C₃N₄ and exceeds the antibacterial performance of the most of the previously reported g-C₃N₄-based photocatalysts. Both the experiments and theoretical calculations demonstrated that the high photocatalytic disinfection performance of AHUCN was derived from the synergistic advantages of their unique holey ultrathin structure and the amino - rich surface in controlling the charge separation and transfer, and most importantly in increasing the photo-production of the dominant antibacterial species, H₂O₂. From the analysis of the reactive oxygen species and rotating disk electrode (RDE) measurements, it was found that the presence of abundant surface amino groups enabled the switch of the oxygen-reduction pathway from the two-step single-electron indirect reduction on holey ultrathin g-C₃N₄ nanosheets (HUCN) to the one-step two-electron direct reduction on AHUCN. The switch of the H₂O₂ production pathway not only facilitated the separation of photogenerated electron-hole pairs but also promoted the generation of reactive oxygen species, greatly enhancing photocatalytic disinfection efficiency.

Enhanced photocatalytic activity of Bi2WO6 with PVP addition for CO2 reduction into ethanol under visible light

The conversion of CO₂ into new carbon-based products, such as fuels and chemicals, is an attractive and promising means of mitigating global energy needs and minimizing environmental damage. Although bismuth tungstate (Bi₂WO₆) as a photocatalyst can promote CO₂ photoreduction, a systematic study for the development of a low-cost and efficient catalyst is needed. Thus, Bi₂WO₆ with different morphologies was successfully synthesized using the hydrothermal method. An experimental design was applied to investigate the effect of synthesis time and PVP (polyvinylpyrrolidone) concentration on catalyst photocatalytic activity. Crystal structures, morphologies, optical absorption, and surface charges of the catalysts were characterized by X-ray diffraction, scanning electron microscope, UV-vis diffuse-reflection spectroscopy, nitrogen adsorption, and zeta potential. All samples exhibited good performance for the photoreduction of CO₂ into ethanol, and both time and PVP concentration were significant in the ethanol yield. Changes in synthesis conditions induced differences in catalyst characteristics, such as morphology, crystallinity, and, predominantly, surface area. Furthermore, PVP addition improved photocatalytic efficiency by up to 258% compared with results without the surfactant. The best sample, W-8h-10%, presented a flower-like morphology and ethanol yield of 68.9 μmol g^-1 h^-1.

Recent advances in visible-light-driven carbon dioxide reduction by metal-organic frameworks

Metal-organic frameworks (MOFs) have emerged as promising materials and have attracted researchers due to their unique chemical and physical properties-design flexibility, tuneable pore channels, a high surface-to-volume ratio that allow their distinct application in diverse research fields-gas storage, gas separation, catalysis, adsorption, drug delivery, ion exchange, sensing, etc. The rapidly growing CO₂ in the atmosphere is a global concern due to the excessive use of fossil fuels in the current era. CO₂ is the prime cause of global warming and should be ameliorated either through adsorption or conversion into value-added products to protect the environment and mankind. Nowadays, MOFs are exploited as a photocatalyst for applications of CO₂ reduction. Since the use of semiconductors limits the use of visible light for photocatalytic reduction of CO₂, MOFs are promising options. The current review describes recent development in the application of MOFs as host, composites, and their derivatives in photocatalytic reduction of CO₂ to CO and different organic chemicals (HCOOH, CH₃OH, CH₄). Efficient charge separation and visible light absorption by incorporation of active sites for efficient photocatalysis have been discussed. The selection of material for high CO₂ uptake and potential strategies for the rational design and development of high-performance catalysts are outlined. Major challenges and future perspectives have also been discussed at the last of the review.

Glycine-Functionalized CsPbBr3 Nanocrystals for Efficient Visible-Light Photocatalysis of CO2 Reduction

Capping ligands are indispensable for the preparation of metal-halide-perovskite (MHP) nanocrystals (NCs) with good stability; however, the long alkyl-chain capping ligands in conventional MHP NCs will be unfavorable for CO₂ adsorption and hinder the efficient carrier separation on the surface of MHP NCs, leading to inferior catalytic activity in artificial photosynthesis. Herein, CsPbBr₃ nanocrystals with short-chain glycine as ligand are constructed through a facile ligand-exchange strategy. Owing to the reduced hindrance of glycine and the presence of the amine group in glycine, the photogenerated carrier separation and CO₂ uptake capacity are noticeably improved without compromising the stability of the MHP NCs. The CsPbBr₃ nanocrystals with glycine ligands exhibit a significantly increased yield of 27.7 μmol g^-1  h^-1 for photocatalytic CO₂ -to-CO conversion without any organic sacrificial reagents, which is over five times higher than that of control CsPbBr₃ NCs with conventional long alkyl-chain capping ligands.

A Mixed-Metal Porphyrinic Framework Promoting Gas-Phase CO2 Photoreduction without Organic Sacrificial Agents

A photoactive porphyrinic metal-organic framework (MOF) has been prepared by exchanging Ti into a Zr-based MOF precursor. The resultant mixed-metal Ti/Zr porphyrinic MOF demonstrates much-improved efficiency for gas-phase CO₂ photoreduction into CH₄ and CO under visible-light irradiation using water vapor compared to the parent Zr-MOF. Insightful studies have been conducted to probe the photocatalysis processes. This work provides the first example of gas-phase CO₂ photoreduction into methane without organic sacrificial agents on a MOF platform, thereby paving an avenue for developing MOF-based photocatalysts for application in CO₂ photoreduction and other types of photoreactions.

Organic-inorganic hybrids for CO2 sensing, separation and conversion

Motivated by the air pollution that skyrocketed in numerous regions around the world, great effort was placed on discovering new classes of materials that separate, sense or convert CO₂ in order to minimise impact on human health. However, separation, sensing and conversion are not only closely intertwined due to the ultimate goal of improving human well-being, but also because of similarities in material prerequisites -e.g. affinity to CO₂. Partly inspired by the unrivalled performance of complex natural materials, manifold inorganic-organic hybrids were developed. One of the most important characteristics of hybrids is their design flexibility, which results from the combination of individual constituents with specific functionality. In this review, we discuss commonly used organic, inorganic, and inherently hybrid building blocks for applications in separation, sensing and catalytic conversion and highlight benefits like durability, activity, low-cost and large scale fabrication. Moreover, we address obstacles and potential future developments of hybrid materials. This review should inspire young researchers in chemistry, physics and engineering to identify and overcome interdisciplinary research challenges by performing academic research but also - based on the ever-stricter emission regulations like carbon taxes - through exchanges between industry and science.

Recent Advances in TiO2-Based Photocatalysts for Reduction of CO2 to Fuels

Titanium dioxide (TiO₂) has attracted increasing attention as a candidate for the photocatalytic reduction of carbon dioxide (CO₂) to convert anthropogenic CO₂ gas into fuels combined with storage of intermittent and renewable solar energy in forms of chemical bonds for closing the carbon cycle. However, pristine TiO₂ possesses a large band gap (3.2 eV), fast recombination of electrons and holes, and low selectivity for the photoreduction of CO₂. Recently, considerable progress has been made in the improvement of the performance of TiO₂ photocatalysts for CO₂ reduction. In this review, we first discuss the fundamentals of and challenges in CO₂ photoreduction on TiO₂-based catalysts. Next, the recently emerging progress and advances in TiO₂ nanostructured and hybrid materials for overcoming the mentioned obstacles to achieve high light-harvesting capability, improved adsorption and activation of CO₂, excellent photocatalytic activity, the ability to impede the recombination of electrons-holes pairs, and efficient suppression of hydrogen evolution are discussed. In addition, approaches and strategies for improvements in TiO₂-based photocatalysts and their working mechanisms are thoroughly summarized and analyzed. Lastly, the current challenges and prospects of CO₂ photocatalytic reactions on TiO₂-based catalysts are also presented.

Single atomic Au induced dramatic promotion of the photocatalytic activity of TiO2 hollow microspheres

Surface oxygen vacancies (Ov) are used to stabilize single atomic Au on the surfaces of TiO₂ hollow microspheres (TiO₂-HMSs), sharply improving their photoreactivity towards acetone oxidation.

Core–shell structured catalysts for thermocatalytic, photocatalytic, and electrocatalytic conversion of CO2

An in-depth assessment of properties of core–shell catalysts and their application in the thermocatalytic, photocatalytic, and electrocatalytic conversion of CO₂into synthesis gas and valuable hydrocarbons.

Boron-titanate monolayer nanosheets for highly selective adsorption of immunoglobulin G

Boron-titanate monolayer nanosheets were prepared through a scalable step by step intercalation approach for anchoring 3-mercaptopropyltriethoxysilane (MPTS) on the surface. MPTS provides clickable sites with 4-vinylphenylboronic acid (VPBA) via a thiol-ene (TE) click reaction to obtain monolayer titanate nanosheets with boronic acid ligands immobilized on the surface. The nanosheets obtained are denoted as VPBA-MPTS-TiNSs, with a lateral dimension of a few dozen nanometers and with a thickness of ca. 3.5 nm. The nanosheets exhibit a superior adsorption capacity of 1669.7 mg g-1 and favorable selectivity for the adsorption of glycoproteins by employing immunoglobulin G (IgG) as the protein model. The adsorbed IgG is thereafter readily collected by using 0.1% (m/v) cetane trimethyl ammonium bromide (CTAB) as the eluent. The practical applications of VPBA-MPTS-TiNSs are further demonstrated by the selective adsorption/purification of IgG from human serum.

Functionalized nitrogen-doped carbon dot-modified yolk-shell ZnFe2O4 nanospheres with highly efficient light harvesting and superior catalytic activity

Volatile organic compounds (VOCs), as hazardous gaseous pollutants, have attracted much attention due to their potential threat to both human health and the environment. Accordingly, photocatalysis technology is seen as a promising technology to control low concentration VOCs due to its mild operation conditions, low energy consumption, and mineralization ability. However, there are some issues with photocatalysts, such as low light utility and fast photogenerated carrier recombination, which need to be addressed for practical applications. In this work, novel nitrogen-doped carbon dot (NCD)-modified ZnFe2O4 yolk-shell nanostructure photocatalysts were fabricated for the first time. The yolk-shell structure of ZnFe2O4 efficiently shortened the photogenerated carrier migration path and enhanced light scattering in its void, while the decorated NCDs accelerated the charge transfer from the bulk to the surface. A series of characterizations was conducted to investigate the crystal structure, elemental status, optical properties, and photocatalytic performance of the obtained composite photocatalysts. The NCD-modified ZnFe2O4 yolk-shell photocatalysts exhibited both a wide spectral absorbance and low carrier recombination, resulting in high photocatalytic activity and degradation ability towards gaseous o-dichlorobenzene. Density functional theory (DFT) calculations further revealed that the NCDs effectively promoted charge transfer and weakened the recombination of photo-generated electron-hole pairs. Additionally, in situ Fourier transform infrared (FTIR) spectroscopy was performed to investigate the degradation path in the photocatalytic process, and an electron paramagnetic resonance (EPR) radical trapping experiment was conducted to unveil the reactive oxygen species involved in the system. Combining the results obtained, the synergistic effect in the enhancement of photocatalysis between NCDs and yolk-shell ZnFe2O4 was schematically proposed.

3D Yolk@Shell TiO2- x/LDH Architecture: Tailored Structure for Visible Light CO2 Conversion

CO₂ photoconversion into hydrocarbon solar fuels by engineered semiconductors is considered as a feasible plan to address global energy requirements in times of global warming. In this regard, three-dimensional yolk@shell hydrogenated TiO₂/Co-Al layered double hydroxide (3D Y@S TiO_{2- x}/LDH) architecture was successfully assembled by sequential solvothermal, hydrogen treatment, and hydrothermal preparation steps. This architecture revealed a high efficiency for the photoreduction of CO₂ to solar fuels, without a noble metal cocatalyst. The time-dependent experiment indicated that the production of CH₃OH was almost selective until 2 h (up to 251 μmol/g_cat. h), whereas CH₄ was produced gradually by increasing the time of reaction to 12 h (up to 63 μmol/g_cat. h). This significant efficiency can be ascribed to the engineering of 3D Y@S TiO_{2- x}/LDH architecture with considerable CO₂ sorption ability in mesoporous yolk@shell structure and LDH interlayer spaces. Also, oxygen vacancies in TiO_{2- x} could provide excess sites for sorption, activation, and conversion of CO₂. Furthermore, the generated Ti³⁺ ions in the Y@S TiO₂ structure as well as connecting of structure with LDH plates can facilitate the charge separation and decrease the band gap of nanoarchitecture to the visible region.

Adjusting the Reduction Potential of Electrons by Quantum Confinement for Selective Photoreduction of CO2 to Methanol

The production of CH₃ OH from the photocatalytic CO₂ reduction reaction (PCRR) presents a promising route for the clean utilization of renewable resources, but charge recombination, an unsatisfying stability and a poor selectivity limit its practical application. In this paper, we present the design and fabrication of 0D/2D materials with polymeric C₃ N₄ nanosheets and CdSe quantum dots (QDs) to enhance the separation and reduce the diffusion length of charge carriers. The rapid outflow of carriers also restrains self-corrosion and consequently enhances the stability. Furthermore, based on quantum confinement effects of the QDs, the energy of the electrons could be adjusted to a level that inhibits the hydrogen evolution reaction (HER, the main competitive reaction to PCRR) and improves the selectivity and activity for CH₃ OH production from the PCRR. The band structures of photocatalysts with various CdSe particle sizes were also investigated quantitatively to establish the relationship between the band energy and the photocatalytic performance.

Rational design of yolk–shell nanostructures for photocatalysis

Yolk–shell structures provide an ideal platform for the rational regulation and effective utilization of charge carriers because of their void space and large surface areas. Furthermore, the efficiency of charge behavior in every step can be further improved by many strategies. This review describes the synthesis of yolk–shell structures and their effect for the enhancement of heterogeneous photocatalysis.

A Molecular CO2 Reduction Catalyst Based on Giant Polyoxometalate {Mo368}

Photocatalytic CO2 reduction in water is one of the most attractive research pursuits of our time. In this article we report a giant polyoxometalate {Mo368} based homogeneous catalytic system, which efficiently reduces CO2 to formic acid with a maximum turnover number (TON) of 27,666, turnover frequency (TOF) of 4,611 h-1 and external quantum efficiency of the reaction is 0.6%. The catalytic system oxidizes water and releases electrons, and these electrons are further utilized for the reduction of CO2 to formic acid. A maximum of 8.3 mmol of formic acid was observed with the loading of 0.3 μmol of the catalyst. Our catalyst material is also stable throughout the reaction. The starting materials for this experiment are CO2 and H2O and the end products are HCOOH and O2. The formic acid formed in this reaction is an important H2 gas carrier and thus significant in renewable energy research.

PEGylated titanate nanosheets: hydrophilic monolayers with a superior capacity for the selective isolation of immunoglobulin G

A novel organic-inorganic hybrid was prepared by anchoring (3-aminopropyl)triethoxysilane (APTES) on the surface of monolayer titanate nanosheets and subsequent modification with hydrophilic polyethylene glycol (PEG). The PEGylated hydrophilic monolayer titanate nanosheets were abbreviated as PEG-APTES-TiNSs, and they exhibit a lateral dimension of dozens of nanometers and a thickness of ca. 1.9 nm. PEGylation of the titanate nanosheets significantly improved their selectivity toward the adsorption of glycoproteins through strong hydrophilic interaction, providing an adsorption capacity of 2540.9 mg g-1 for immunoglobulin G (IgG). The retained IgG is readily collected at a recovery rate of 83.4% with 0.5% (m/v) ammonium hydroxide (NH4OH) as the stripping reagent. PEG-APTES-TiNSs are applied for the selective adsorption of IgG from human serum, which is further confirmed by SDS-PAGE assay.

CO2 Reduction: From the Electrochemical to Photochemical Approach

Increasing CO2 concentration in the atmosphere is believed to have a profound impact on the global climate. To reverse the impact would necessitate not only curbing the reliance on fossil fuels but also developing effective strategies capture and utilize CO2 from the atmosphere. Among several available strategies, CO2 reduction via the electrochemical or photochemical approach is particularly attractive since the required energy input can be potentially supplied from renewable sources such as solar energy. In this Review, an overview on these two different but inherently connected approaches is provided and recent progress on the development, engineering, and understanding of CO2 reduction electrocatalysts and photocatalysts is summarized. First, the basic principles that govern electrocatalytic or photocatalytic CO2 reduction and their important performance metrics are discussed. Then, a detailed discussion on different CO2 reduction electrocatalysts and photocatalysts as well as their generally designing strategies is provided. At the end of this Review, perspectives on the opportunities and possible directions for future development of this field are presented.

Activation of peroxymonosulfate by nitrogen-functionalized sludge carbon for efficient degradation of organic pollutants in water

Nitrogen-functionalized sludge carbon (NSC) was prepared by urea-mediated pyrolysis of sewage sludge (SS) and was introduced, for the first time, as a potential metal-free catalyst to activate peroxymonosulfate (PMS) for oxidative removal of organic pollutants in water. The nitrogen functionalization of NSC catalysts significantly affected the chemical micro-environments as well as microstructures (morphology and porosity), improving the PMS activation activity towards removing various pollutants, e.g., acid orange 7, phenol and rhodamine B. On the basis of quenching studies and electron paramagnetic resonance, the formed dominant reactive oxidative species (ROS) in the NSC/PMS system was clarified to be nonradical singlet oxygen, in addition to the typical radical ROSs, sulfate and hydroxyl radicals. The incorporated pyridine N, graphite N and pristine CO in the NSC framework promoted the generation of ROS. This study provided new insights into environmentally friendly resourcing SS and exploiting novel cost-effective metal-free catalyst for PMS activation.