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In the present work, non-precious Cu2O and Cu loaded hydrogenated black TiO2 nanoparticles were prepared, and the H2 evolution and the removal of a waterbased organic pollutant under UV light were studied. The results revealed that the BTiO2/Cu2O/Cu (TC6-350) sample exhibited an improved photocatalytic hydrogen evolution performance, about 47 times higher than that of the TiO2, and photocatalytic degradation of the Rhodamine B aqueous solution about 2.2 times faster than the TiO2. The enhanced photocatalytic activity can be attributed to the integration of energy band alignment, effective carrier separation, and low charge transfer resistance. In addition, the constructed B–TiO2/Cu2O/Cu nanocomposite exhibited light stability, making it a long-term competitive photocatalyst for H2 evolution. Therefore, the B–TiO2/Cu2O photocatalyst is a promising candidate for a variety of photocatalytic applications.

The development of new and efficient non-precious metal electronic additives is of great significance for the photocatalytic decomposition of water to produce hydrogen. Molybdenum sulfide is the most promising electronic assistant to replace the precious metal Pt. However, its weak electrical conductivity and rare unsaturated S atom active sites severely restrict the improvement of the photocatalytic hydrogen production efficiency. In this study, an amorphous molybdenum sulfide electronic promoter modified TiO2 (TiO2/a-MoSx) photocatalytic material was synthesized by the in-situ adsorption-photodeposition conversion method, aiming to improve the photocatalytic hydrogen production performance of semiconductor materials. The results of the photocatalysis experiments showed that, compared to pure TiO2 and a-MoSx photocatalysts, the TiO2/a-MoSx photocatalytic materials had a significantly improved photocatalytic hydrogen production performance, while TiO2/a-MoSx-8p photocatalysts had the best photocatalytic hydrogen production activity. The hydrogen evolution efficiency reached 35.2 mmol g−1 within two hours. At the same time, the analysis of the hydrogen production performance of four cycles showed that it had a good stability. The characterization results showed that the a-MoSx cocatalyst can not only increase the specific surface area of the catalyst and provide more active sites, but also effectively capture the photogenerated electrons of TiO2, thereby greatly improving the separation efficiency of the photogenerated charges and enhancing the catalytic activity. Therefore, this study provides a simple and effective strategy for the design of high-performance a-MoSx-based cocatalysts to stably carry out in-situ photocatalytic H2 release.

Nowadays, the environmental crisis caused by using fossil fuels and CO2 emissions has become a universal concern in people’s lives. Photocatalysis is a promising clean technology to produce hydrogen fuel, convert harmful components such as CO2, and degrade pollutants like dyes in water. There are various strategies to improve the efficiency of photocatalysis so that it can be used instead of conventional methods, however, the low efficiency of the process has remained a big drawback. In recent years, high-pressure torsion (HPT), as a severe plastic deformation (SPD) method, has shown extremely high potential as an effective strategy to improve the activity of conventional photocatalysts and synthesize new and highly efficient photocatalysts. This method can successfully improve the activity by increasing the light absorbance, narrowing the bandgap, aligning the band structure, decreasing the electron–hole recombination, and accelerating the electron–hole separation by introducing large lattice strain, oxygen vacancies, nitrogen vacancies, high-pressure phases, heterojunctions, and high-entropy ceramics. This study reviews the recent findings on the improvement of the efficiency of photocatalysts by HPT processing and discusses the parameters that lead to these improvements.

The upgrading of plant-based oils to liquid transportation fuels through the hydrotreating process has become the most attractive and promising technical pathway for producing biofuels. This work produced bio-jet fuel (C9–C14 hydrocarbons) from palm olein oil through hydrocracking over varied metal phosphide supported on porous biochar catalysts. Relative metal phosphide catalysts were investigated for the highest performance for bio-jet fuel production. The palm oil’s fiber-derived porous biochar (PFC) revealed its high potential as a catalyst supporter. A series of PFC-supported cobalt, nickel, iron, and molybdenum metal phosphides (Co-P/PFC, Ni-P/PFC, Fe-P/PFC, and Mo-P/PFC) catalysts with a metal-loading content of 10 wt.% were synthesized by wet-impregnation and a reduction process. The performance of the prepared catalysts was tested for palm oil hydrocracking in a trickle-bed continuous flow reactor under fixed conditions; a reaction temperature of 420 °C, LHSV of 1 h−1, and H2 pressure of 50 bar was found. The Fe-P/PFC catalyst represented the highest hydrocracking performance based on 100% conversion with 94.6% bio-jet selectivity due to its higher active phase dispersion along with high acidity, which is higher than other synthesized catalysts. Moreover, the Fe-P/PFC catalyst was found to be the most selective to C9 (35.4%) and C10 (37.6%) hydrocarbons.

Cellulose nanofiber (CNF)-derived functional papers hold promise for application in various fields due to their unique properties such as gas barriers, high strength, transparency, etc. Mechanochemistry offers environmentally benign and sustainable synthesis of the functionalized CNFs (e.g., in combination with photocatalytic TiO2). The CNFs could also favorably work to produce oxygen vacancies in TiO2 that enables visible responsive photocatalysis. What microstructural and physicochemical changes then occur on the CNF sol during the milling treatment? In this study, changes in the microstructure of the CNF aqueous sol before/after planetary ball milling were investigated based on its rheological behavior, crystallinity, and diameter distribution. The surface activity of the CNFs was additionally characterized by water vapor adsorption. A decreased thixotropy hysteresis loop observed in the low milling speed (100 rpm)-treated CNFs indicated a weaker interaction among the fibers, but still having a three-dimensional structure. A further increase in the milling speed (300 rpm) could collapse them. A decreased X-ray diffraction peak intensity of the (200) plane observed in the 500-rpm-treated CNFs could indicate a split in the fiber’s bundle as well as shredding. The increased amount of water vapor adsorption in the 500-rpm treated CNFs also supports exposure of the new surface with hydroxyl groups derived from the glucose unit. Such newly formed hydroxyl groups can be effective reaction sites with, for example, the TiO2 precursor and perhaps favorably works to improve the photocatalytic performance.Graphic abstract

The NMR-based solvent relaxation technique, a non-invasive tool to characterize the surface of particles, which are dispersed in a liquid, was applied to characterize the nanoparticles’ aggregation structure. The liquid molecules in a dispersion undergo a rapid exchange between the bound states at the interface and highly mobile free states in a bulk liquid. The relaxation time of the liquid molecules bound on the particle surface is shorter than that of the free states liquid. By detecting how much liquid is bound on the particle surface, the wetted specific surface area (SNMR) can be determined. In this study, it was clarified that the water adsorbed at more than a 1.138 layer from the silica surface can be detected by the NMR and the maximum limitation ranged from 2.160 and 3.336 layers. The model aggregates with an artificial solid neck among the particles were mixed with the silica nanoparticle dispersion. Although the determined SNMR was underestimated compared to SBET from gas adsorption, even a low ratio (5 mass%) of the model aggregates in the dispersion can be detected.

A short-length cellulose nanofiber (CNF) aqueous sol, prepared by a high-pressure homogenizer, showed a rapid longer relaxation time ( T 2 ) in the low-field 1 H-nuclear magnetic resonance (NMR) when diluted from 20 wt% to 1 wt%. Magnetic stirring for 30 min disentangled the fiber networks and the fragmented fibers appeared in the 1 wt% CNF sol. A decrease in the specific viscosity of the diluted sols changed the rheological behavior from exponential to linear below 1 wt%, suggesting a significant decrease in the inter-fibril interaction. The small angle x-ray scattering (SAXS) with the generalized indirect Fourier transformation (GIFT) also indicated similar changes in the fiber flocculation structure without a change in the fiber size. The increasing viscosity upon severe fiber fragmentation by a high-pressure homogenizer may be ascribed to tighter holding of the interfibril water molecules. The time-domain (TD)-NMR fully supported the estimation that the transverse relaxation time ( T 2 ) showed consistently short for the 2 wt%, became shorter with the stirring time when diluted from 5 wt% to 2 wt%, and showed long upon dilution from 20 wt% to 2 wt%. Understanding the complex behavior of the highly viscous CNF sols during a simple dilution process may pave the way for developing CNF-related technology.

The increasing demand for sustainable and cost-effective energy storage solutions has driven interest in biomass-derived carbon materials for supercapacitor electrodes. This study explores the valorization of coconut residue (CR), an abundant agricultural waste, as a carbon precursor for nanoporous carbon (NPC) production. NPC was synthesized via hydrothermal carbonization (HTC) of CR, followed by chemical activation using potassium hydroxide (KOH) at varying temperatures (700, 800, and 900 °C). The effects of activation temperature on the structure and electrochemical performance of the NPC were systematically investigated. The activated materials exhibited amorphous, highly porous structures, with surface areas increasing alongside activation temperature—reaching a maximum of 1969 m2 g−1 at 900 °C. Electrochemical characterization was conducted using a three-electrode setup through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) in a 1 M Na2SO4 electrolyte. The sample activated at 900 °C with a CR:KOH weight ratio of 1:2.5 achieved the highest specific capacitance of 52 F g−1 at a specific current of 1 A g−1. These findings underscore the potential of CR as a low-cost and sustainable raw material for fabricating efficient electrode materials in energy storage applications.

Severe plastic deformation (SPD) is effective in producing bulk ultrafine-grained and nanostructured materials with large densities of lattice defects. This field, also known as NanoSPD, experienced a significant progress within the past two decades. Beside classic SPD methods such as high-pressure torsion, equal-channel angular pressing, accumulative roll-bonding, twist extrusion, and multi-directional forging, various continuous techniques were introduced to produce upscaled samples. Moreover, numerous alloys, glasses, semiconductors, ceramics, polymers, and their composites were processed. The SPD methods were used to synthesize new materials or to stabilize metastable phases with advanced mechanical and functional properties. High strength combined with high ductility, low/room-temperature superplasticity, creep resistance, hydrogen storage, photocatalytic hydrogen production, photocatalytic CO 2 conversion, superconductivity, thermoelectric performance, radiation resistance, corrosion resistance, and biocompatibility are some highlighted properties of SPD-processed materials. This article reviews recent advances in the NanoSPD field and provides a brief history regarding its progress from the ancient times to modernity. Abbreviations: ARB: Accumulative Roll-Bonding; BCC: Body-Centered Cubic; DAC: Diamond Anvil Cell; EBSD: Electron Backscatter Diffraction; ECAP: Equal-Channel Angular Pressing (Extrusion); FCC: Face-Centered Cubic; FEM: Finite Element Method; FSP: Friction Stir Processing; HCP: Hexagonal Close-Packed; HPT: High-Pressure Torsion; HPTT: High-Pressure Tube Twisting; MDF: Multi-Directional (-Axial) Forging; NanoSPD: Nanomaterials by Severe Plastic Deformation; SDAC: Shear (Rotational) Diamond Anvil Cell; SEM: Scanning Electron Microscopy; SMAT: Surface Mechanical Attrition Treatment; SPD: Severe Plastic Deformation; TE: Twist Extrusion; TEM: Transmission Electron Microscopy; UFG: Ultrafine Grained This article comprehensively reviews recent advances on development of ultrafine-grained and nanostructured materials by severe plastic deformation and provides a brief history regarding the progress of this field.

Waste lignin (WL) from the pulp mill and paper was studied for its potential application to prepare the nanoporous carbon with high porosity via carbonization assisted acid activation. The effect of acid activation such as HNO3, HCl, H2SO4, and H3PO4 on lignin transformation to nanoporous carbon investigated. The physicochemical properties of nanoporous carbon were comprehensively characterized through N2 sorption, Scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR), respectively. N2 sorption revealed that the condition using 5% vol of phosphoric acid activation at carbonization temperature of 700°C for 2 h exhibited the highly porous structure of carbon nanoparticles with a total pore volume of 0.035 cm3/g. With the properly selecting process variables of waste lignin development could be producing high porosity nanoporous carbon.