Solar photothermochemical alkane reverse combustion

CO2 activation and dissociation on In2O3(110) supported PdnPt(4-n) (n = 0-4) catalysts: a density functional theory study

Converting CO2 into valuable chemicals via catalytic reactions can mitigate both the greenhouse effect and energy shortage problems, thus designing efficient catalysts have attracted considerable attention over the past decades. In this work, a density functional theory (DFT) calculation was carried out to investigate the CO2 activation and dissociation processes on various PdnPt(4-n)/In2O3 (n = 0-4) catalysts. The PdnPt(4-n)/In2O3 models were initially built, and the interface sites of PdnPt(4-n)/In2O3 for CO2 adsorption were confirmed among cluster sites and substrate sites. The CO2 adsorption geometries, charger transfer, and projected density of states (PDOS) were analyzed to study the CO2-PdnPt(4-n)/In2O3 interactions. From the adsorbed *CO2, the transition states (TSs) for CO2 dissociation to form *CO and *O were gained to reveal the characteristics of the activated CO2δ-. Overall, according to the adsorption energy Eads results, the bimetallic PdPt3/In2O3 and Pd3Pt/In2O3 catalysts showed the strongest and weakest CO2 adsorption stabilities, respectively, while the Pd element addition decreases the barriers for CO2 dissociation with the priority order of Pd4 > Pd3Pt > Pd2Pt2 > PdPt3 > Pt4. The Brønsted-Evans-Polanyi (BEP) relation between activation barriers (Eb) and reaction energies E was obtained for the CO2 dissociation mechanism on PdnPt(4-n)/In2O3 catalysts with the equation of E = 0.20Eb + 0.40. Finally, the optimal Pd2Pt2/In2O3 catalyst for CO2 activation and dissociation was proposed. This study provides useful information for CO2 activation and conversation procedures on bimetal-oxide catalysts, and helps to take the optimal design of PdPt/In2O3 catalysts for the CO2 reaction.

Isomerization of n-C5/C6 Bioparaffins to Gasoline Components with High Octane Number

The thermal and catalytic conversion processes of alternative feedstocks (e.g., waste and biomass) to different engine fuels can result in the formation of a significant amount of light hydrocarbons as by-products in the boiling range of gasoline. The properties of these C5/C6 hydrocarbons need to be improved due to many reasons, e.g., their benzene content, and/or poor oxidation stability (high olefin content) and low octane number (<60). The aim of the research work was to increase the octane number of benzene containing C5/C6 bioparaffin fractions by catalytic isomerization. These by-products were obtained from special hydrocracking of waste cooking oil to hydrocarbons in the boiling range of aviation turbine fuels (JET fuels)/diesel fuels. Experiments were carried out in a reactor system containing down-flow tubular reactors over Pt/Al2O3/Cl and Pt/H-Mordenite/Al2O3 catalysts at 115–145 °C and 230–270 °C, respectively. Based on the results obtained at different process parameter combinations, it was concluded that the hydrogenation of benzene was complete over both catalysts, and the liquid yields were higher (ca. 98% > ca. 93 %) in the case of Pt/Al2O3/Cl. In addition, the octane number was also enhanced (ca. 32 > ca. 27 unit) in the products compared to the feedstock. This was because a higher isoparaffin content can be obtained at a lower operating temperature. Moreover, cracking side reactions take place to a lesser extent. The utilization of these isomerized bio-origin light fractions can contribute to the competitiveness of second-generation biofuels.

Photo-thermal reactions of ethanol over Ag/TiO2 catalysts. The role of silver plasmon resonance in the reaction kinetics

Photo-thermal catalytic reactions of ethanol over Ag/TiO₂ were conducted in order to probe into the role of plasmonic resonance response in the reaction kinetics.

Insight into the role of UV-irradiation in photothermal catalytic Fischer–Tropsch synthesis over TiO2 nanotube-supported cobalt nanoparticles

To explore an efficient catalytic system with high activity and selectivity is the key to improve Fischer–Tropsch synthesis (FTS) technology and the main focus in the academic field.

Electrospun titania fiber mats spin coated with thin polymer films as nanofibrous scaffolds for enhanced cell proliferation

The incorporation of inorganic materials into electrospun nanofibres has recently gained considerable attention for the development of extracellular matrix-like scaffolds with improved mechanical properties and enhanced biological functions for tissue engineering applications. In this study, polymer-inorganic composite fibres consisting of poly(2-ethyl-2-oxazoline) (PEOXA) and tetrabutyl titanate as the titanium precursor were successfully fabricated through a combined sol-gel/electrospinning approach. PEOXA/Ti(OR)_n composite fibres were obtained with varying amounts of polymer and titanium precursors. Calcinations of the composite fibres were performed at varying temperatures to produce TiO₂ fibres (TiO₂ -T-60) with anatase, anatase/rutile mixed phase, and rutile crystal structures. Thin polymer films (i.e., poly(2-ethyl-2-oxazoline) (PEOXA), polycaprolactone (PCL), and poly(methyl methacrylate) (PMMA)) were subsequently deposited onto TiO₂ -T-60 fibre mats by spin coating to facilitate handling of the electrospun substrates after calcination, which are rather brittle and disintegrate easily, and to probe cell-materials interactions. The cellular behaviour of mouse L929 fibroblasts after culture periods of 1-5 days was compared on the following fibre scaffolds: PEOXA/Ti(OR)_n , TiO₂ -T-60 (T = 600, 650, and 700 °C), TiO₂ -T-60 spin-coated with thin PCL film (PCL/TiO₂ -T-60), and pure PCL. The results obtained from in vitro cell culture studies for the lactate dehydrogenase release assay and confocal microscopic visualization pointed out the synergistic interplay between the TiO₂ crystal structure and spin-coated PCL film in facilitating cell interactions with the scaffold surface. The L929 cells were observed to adhere and proliferate better on the surface of TiO₂ -700-60 having the rutile structure than on the surfaces of TiO₂ -600-60 and TiO₂ -650-60 fibre scaffolds with anatase and anatase/rutile mixed phase structures, respectively.

Direct Coupling of Thermo- and Photocatalysis for Conversion of CO2 -H2 O into Fuels

Photocatalytic CO₂ reduction into renewable hydrocarbon solar fuels is considered as a promising strategy to simultaneously address global energy and environmental issues. This study focused on the direct coupling of photocatalytic water splitting and thermocatalytic hydrogenation of CO₂ in the conversion of CO₂ -H₂ O into fuels. Specifically, it was found that direct coupling of thermo- and photocatalysis over Au-Ru/TiO₂ leads to activity 15 times higher (T=358 K; ca. 99 % CH₄ selectivity) in the conversion of CO₂ -H₂ O into fuels than that of photocatalytic water splitting. This is ascribed to the promoting effect of thermocatalytic hydrogenation of CO₂ by hydrogen atoms generated in situ by photocatalytic water splitting.

A New Energy-Saving Catalytic System: Carbon Dioxide Activation by a Metal/Carbon Catalyst

The conversion of CO₂ into useful chemicals is an attractive method to reduce greenhouse gas emissions and to produce sustainable chemicals. However, the thermodynamic stability of CO₂ means that a lot of energy is required for its conversion into chemicals. Here, we suggest a new catalytic system with an alternative heating system that allows minimal energy consumption during CO₂ conversion. In this system, electrical energy is transferred as heat energy to the carbon-supported metal catalyst. Fast ramping rates allow high operating temperatures (T_app =250 °C) to be reached within 5 min, which leads to an 80-fold decrease of energy consumption in methane reforming using CO₂ (DRM). In addition, the consumed energy normalized by time during the DRM reaction in this current-assisted catalysis is sixfold lower (11.0 kJ min^-1 ) than that in conventional heating systems (68.4 kJ min^-1 ).

Cyborgian Material Design for Solar Fuel Production: The Emerging Photosynthetic Biohybrid Systems

Photosynthetic biohybrid systems (PBSs) combine the strengths of inorganic materials and biological catalysts by exploiting semiconductor broadband light absorption to capture solar energy and subsequently transform it into valuable CO₂-derived chemicals by taking advantage of the metabolic pathways in living organisms. In this work, we first traverse through a brief history of recent PBSs, demonstrating the modularity and diversity of possible architectures to rival and, in many cases, surpass the performance of chemistry or biology alone before envisioning the future of these hybrid systems, opportunities for improvement, and its role in sustainable living here on earth and beyond.

Revisiting the behaviour of BiVO4as a carbon dioxide reduction photo-catalyst

Bismuth vanadate is a widely known photocatalyst for the hydro-reduction of CO₂.

Density functional theory study on the thermodynamics and mechanism of carbon dioxide capture by CaO and CaO regeneration

The bond length between the C atom in CO₂ and O atom in CaO was about 1.39–1.42 Å, and the bond length of C–O in adsorbed CO₂ was prolonged to 1.26–1.27 Å, while the O–C–O angle of adsorbed CO₂ was about 129°.