Low Conversion Research Articles

Event-based high-resolution neutron image formation analysis using intensified CMOS cameras.

We present a versatile optical setup for high-resolution neutron imaging with an adaptable field of view and magnification that can resolve individual neutron absorption events with an image intensifier and a CMOS camera. Its imaging performance is characterized by evaluating the resolution limits of the individual optical components and resulting design aspects are discussed. Neutron radiography measurements of a Siemens star pattern were performed in event mode acquisition comparing two common high-resolution neutron scintillators, crystalline Gadolinium Gallium Garnet (GGG) and powdered Gadolinium Oxysulfide (GOS). An analysis of the light signature caused by neutron absorption events is performed and some resulting issues for both GGG and GOS regarding optical system design are addressed. Both scintillators reach similar resolution (4-5 m) in event mode acquisition despite different light emission characteristics. The findings suggest that, in the case of GOS, the resolution is limited by the size of the light clusters which in turn originate from the photon scattering at the boundaries of the powder particles comprising it, while with GGG the lower light conversion efficiency makes it challenging to collect enough photons to trigger sufficient signal amplification in the image intensifier. Overall, the proposed event-based evaluation of scintillators allows for quantifying and optimizing various design parameters, which is much more complex than adopting conventional methods based on integrated images.

Simulation and Optimization of a Hybrid Photovoltaic/Li-Ion Battery System

The coupling of solar cells and Li-ion batteries is an efficient method of energy storage, but solar power suffers from the disadvantages of randomness, intermittency and fluctuation, which cause the low conversion efficiency from solar energy into electric energy. In this paper, a circuit model for the coupling system with PV cells and a charge controller for a Li-ion battery is presented in the MATLAB/Simulink environment. A new three-stage charging strategy is proposed to explore the changing performance of the Li-ion battery, comprising constant-current charging, maximum power point tracker (MPPT) charging and constant-voltage charging stages, among which the MPPT charging stage can achieve the fastest maximum power point (MPP) capture and, therefore, improve battery charging efficiency. Furthermore, the charge controller can improve the lifetime of the battery through the constant-current and constant-voltage charging scheme. The simulation results indicate that the three-stage charging strategy can achieve an improvement in the maximum power tracking efficiency of 99.9%, and the average charge controller efficiency can reach 96.25%, which is higher than that of commercial chargers. This work efficiently matches PV cells and Li-ion batteries to enhance solar energy storages, and provides a new optimization idea for hybrid PV/Li-ion systems.

Towards Photothermal Acid Catalysts Using Eco-Sustainable Sulfonated Carbon Nanoparticles—Part II: Thermal and Photothermal Catalysis of Biodiesel Synthesis

The main goal of this work is to evaluate the ability of sulfonated carbon nanoparticles (SCNs) to induce photothermal catalysis of the biodiesel synthesis reaction (transesterification of natural triglycerides (TGs) with alcohols). Carbon nanoparticles (CNs) are produced by the carbonization of cross-linked resin nanoparticles (RNs). The RNs are produced by condensation of a phenol (resorcinol or natural tannin) with formaldehyde under ammonia catalysis (Stober method). The method produces nanoparticles, which are carbonized into carbon nanoparticles (CNs). The illumination of CNs increases the temperature proportionally (linear) to the nanoparticle concentration and exposure time (with saturation). Solid acid catalysts are made by heating in concentrated sulfuric acid (SEAr sulfonation). The application of either light or a catalyst (SCNs) (at 25 °C) induced low conversions (<10%) for the esterification reaction of acetic acid with bioethanol. In contrast, the illumination of the reaction medium containing SCNs induced high conversions (>75%). In the case of biodiesel synthesis (transesterification of sunflower oil with bioethanol), conversions greater than 40% were observed only when light and the catalyst (SCNs) were applied simultaneously. Therefore, it is possible to use sulfonated carbon nanoparticles as photothermally activated catalysts for Fischer esterification and triglyceride transesterification (biodiesel synthesis).

Kinetic analysis on low‐temperature oxidation of wood pellets by isothermal microcalorimetry

AbstractLow‐temperature chemical oxidation is the major driver of self‐heating during storage of wood pellets and its kinetics is essential to describe the heat evolution. In the present work, isothermal microcalorimetry was used to characterize heat generation behavior of three types of wood pellets (pine, fir, and redwood pellets) at 30–70°C. The obtained data were employed to derive the kinetics of low‐temperature oxidation by the peak power, iso‐conversional method, and non‐steady analysis. The consistency and applicability of the kinetics derived by the three methods were evaluated. Kinetic parameters determined by the peak power method were observed to match those from the iso‐conversional method at lower conversions of the oxidation for heat generation. The kinetics derived by the iso‐conversional method indicated the oxidation reactivity generally decreasing and activation energy increasing with the conversion because of O2 consumption and reaction mechanism changing. With the impact of O2 consumption considered separately, the kinetics from the non‐steady analysis is capable of describing the evolution of heat power with the conversion and also consistent with that from the peak power method in describing intrinsic reactivity of pellet materials. The kinetics from the peak power and iso‐conversional methods lump the impact of O2 concentration with the reaction reactivity, suggesting their applications requiring additional models for connecting with O2 consumption.

Engineering Co Single Atoms in Ultrathin BiOCl Nanosheets for Boosted CO2 Photoreduction

AbstractDespite the development of a range of photocatalysts for CO2 reduction, the practical applications are significantly limited by low conversion efficiencies and their reliance on sacrificial agents, which are rooted in thermodynamic and kinetic challenges related to CO2 conversion. Here, the engineering of Co single atoms in ultrathin single‐crystal BiOCl nanosheets for boosted photocatalytic CO2 reduction is reported. The engineering of Co atoms modulates the distribution of photogenerated charges at the catalyst surface, controlling key surface reaction dynamics and suppressing surface electron‐hole recombination. This modulation also improves light absorption and enhances CO2 adsorption and activation, leading to more efficient surface reactions. Notably, CO2 is stably adsorbed onto the (001) face of BiOCl through a Bi‐O‐C(= O)‐Co‐O coordination unit, which lowers the activation energy for CO2 reduction and reduces the formation energy of COOH− intermediates. As a result, the BiOCl photocatalysts achieve a CO formation rate of 183.9 µmol g−1 h−1, when irradiated with a 300 W Xe lamp without cocatalysts or sacrificial agents. It represents an ≈13‐fold increase compared to that of pristine BiOCl, and surpasses most reported Bi‐based photocatalysts to date. Current work provides valuable insights into engineering of single atoms for developing advanced CO2‐reduction photocatalysts.

The Buddleja globosa (Matico) as Natural Dye Sensitized Solar Cell : an experimental and theoretical studies based in TD-DFT/ periodic-DFT

The dye sensitizers coming from Buddleja Globosa, a Chilean regional flora, were analyzed and evaluated as a natural dye for the assembly of DSSC. The behavior toward the photoexcitation and electron injection steps was analyzed using time dependent functional theory (TD-DFT) and periodic (Periodic-DFT) calculations using a dye@(TiO2)48 model. The molecules analyzed present in the leaves were verbascoside, luteolin 7-O-glucoside, apigenin 7-O-glucoside, luteolin and gallic acid. The photoexcitation is driven by a π−π* transition localized in the frontier orbitals. These exhibit a ΔEHOMO−LUMO of approximately 4.0 eV which is very broad to facilitate an efficient photoexcitation process even though the LUMO density is localized in the acceptors group. In the adsorption and electron injection was found that the gallic acid and verbascoside facilitate a greater electron transport toward the metallic surface than the other dyes (ΔGinj = -1.52 and -1.03 eV, respectively). This was explained due to a low electron and hole reorganization energy in the gallic acid and verbacoside, respectively. Therefore, the greatest electron injection is originated due to a fast electron-hole transfer. Experimentally, a low overall conversion efficiency (η) was found. Thus, based in the computational discussion, this low efficiency is governed by the behaviour of the photoexcitation and not by the electron injection response.

Preparation activated tailings by pH swing process: Towards yielding cemented tailings backfill and in-situ CO2 mineralization

In-situ CO2 mineralization of tailings has shown great potential for large-scale CO2 sequestration, but its development is seriously limited by the low CO2 conversion rate. This study proposed an innovative pH swing process to produce activated tailings through magnesium extraction from raw tailings and subsequent leachate precipitation. By the combination of activated tailings and high-belite calcium sulfoaluminate cement, a new type of cemented activated tailings backfill (CATB) was developed. The results demonstrate that 82.33% of magnesium is extracted from raw tailings and precipitates in the form of Mg(OH)2 serving as the dominating carbonation active phase during the pH swing process. Besides the aragonite forms in the carbonated cemented raw tailings backfill (CRTB), carbonated CATB also contains calcite, nesquehonite, and hydromagnesite. Substituting activated tailings for raw tailings led to the higher CO2 absorption capability (ranging from 8.88% to 14.17% with various binder-to-tailings ratios). These indicate that the activated tailings have a promising application scenario in large scale in-situ CO2 mineralization.

TME-Activated MnO2/Pt Nanoplatform of Hydroxyl Radical and Oxygen Generation to Synergistically Promote Radiotherapy and MR Imaging of Glioblastoma.

Radiotherapy (RT) is currently recognized as an important treatment for glioblastoma (GBM), however, it is associated with several challenges. One of these challenges is the radioresistance caused by hypoxia, whereas the other is the low conversion efficiency of the strongly oxidized hydroxyl radical (•OH), which is produced by the decomposition of water due to high-energy X-ray radiation. These factors significantly limit the clinical effectiveness of radiotherapy. To address these limitations, we developed a highly stable and efficient nanoplatform (MnO2/Pt@BSA). Compared to MnO2@BSA, this platform demonstrates high stability, a high yield of oxygen (O2), enhanced production of •OH, and reduced clearance of •OH. The system exhibited increased O2 production in vitro and significantly improved oxygen production efficiency within 100 s at the Pt loading of 38.7%. Furthermore, compared with MnO2, the expression rate of hypoxia-inducible factor (HIF-1α) in glioma cells treated with MnO2/Pt decreased by half. Additionally, the system promotes •OH generation and consumes glutathione (GSH), thereby inhibiting the clearance of •OH and enhancing its therapeutic effect. Moreover, the degradation of the nanoplatform produces Mn2+, which serves as a magnetic resonance imaging (MRI) contrast agent with a T1-weighted enhancement effect at the tumor site. The nanoplatform exhibited excellent biocompatibility and performed multiple functions related to radiotherapy, with simpler components. In U87 tumor bearing mice model, we utilized MnO2/Pt nanocatalysis to enhance the therapeutic effect of radiotherapy on GBM. This approach represents a novel and effective strategy for enhancing radiotherapy in gliomas, thereby advancing the field of catalytic radiotherapy and glioma treatment.

Erbium chloride‐mediated nucleation/crystallization control for high‐performance tin‐based perovskite solar cells

AbstractTin‐halide perovskite solar cells (THPSCs), while offering low toxicity and high theoretical power conversion efficiency, suffer from inferior device performance compared to lead‐based counterparts. The primary limitations arise from challenges in fabricating high‐quality perovskite films and mitigating the oxidation of Sn2+ ions, which leads to severe non‐radiative voltage losses. To address these issues, we incorporate the rare‐earth element erbium chloride (ErCl3) into PEA0.15FA0.70EA0.15SnI2.70Br0.30 perovskite to effectively control the nucleation and crystal growth, significantly influencing the morphology of the perovskite films. As a result, the ErCl3‐processed THPSC exhibits an impressive open‐circuit voltage (VOC) of 0.83 V and power conversion efficiency (PCE) of 14.0% with the superior light and air stability, compared to the control device (VOC = 0.77 V and PCE = 12.8%). This ErCl3‐strategy provides a feasible solution for high‐performance THPSCs by regulating nucleation/crystallization kinetics and mitigating excessive crystal defects during the preparation process of lead‐free perovskites.image

Enhancing Enzymatic Hydrolysis of Rice Straw by Acid-Assisted Mechanocatalytic Depolymerization Pretreatment

The inherent complexity of cellulose, hemicellulose, and lignin contributes to the recalcitrance of lignocellulosic biomass, resulting in a low conversion efficiency and high cost of bioethanol conversion. Pretreatment methods that disrupt the plant cell structure of lignocellulose, such as straw, can significantly enhance the conversion efficiency. In this study, we utilized an acid-assisted mechanocatalytic depolymerization technique to pretreat rice straw, and the results demonstrated a significant disruption of the cellulose structure of the straw. Compared to the untreated straw, the particle size of pretreated straw reduced from 279 μm to 11.8 μm, the crystallinity of cellulose decreased from 43.05% to 22.71%, the specific surface area increased by 177%, and the surface oxygen-to-carbon ratio (O/C) ratio was enhanced by 75%. The changes in microstructure enabled the pretreated straw to achieve a total sugar yield of over 95% within 12 h of enzymatic hydrolysis, significantly superior to the 36.24% yield from untreated straw, the 45.20% yield from acid impregnated straw, and the 73.25% yield from ball milled straw. Consequently, acid-assisted mechanocatalytic depolymerization emerges as a highly effective pretreatment strategy to enhance both the enzymatic hydrolysis and the overall conversion efficiency of rice straw.

Flexible Narrow Bandgap Sn-Pb Perovskite Solar Cells with 21% Efficiency Using N,N'-Carbonyldiimidazole Treatments.

Flexible tin-lead (Sn-Pb) mixed perovskite solar cells (PSCs) are among the promising flexible photovoltaics, owing to the narrow bandgap (NBG) of Sn-Pb perovskites, flexible and wearable features, and their role as a critical component in all-perovskite tandem photovoltaics. However, the flexible Sn-Pb PSCs suffer from a low power conversion efficiency, no higher than 18.5%, along with limited stability. Herein, we reported an efficient and stable flexible NBG Sn-Pb PSC via an N,N'-carbonyldiimidazole (CDI) passivation strategy. CDI, with strong adsorption energy, preferentially binds to Sn2+ compared with oxygen (O2), thus effectively inhibiting the adsorption of O2 on perovskite surfaces. The transfer of electron density around Sn2+ dramatically decreased, thus suppressing Sn2+ oxidation. The CDI treatments endowed the Sn-Pb mixed films with fewer defects, improved crystallinity, better morphology, and matched energy-level alignment. The flexible Sn-Pb devices exhibited a high PCE of 21.02%. Besides, the devices showed enhanced stability and promoted flexibility. This work provides a pathway to visibly increase the efficiency and stability of the flexible Sn-Pb mixed photovoltaic cells.

Enhancing Thermoelectric Performance of Mg3Sb2 Through Substitutional Doping: Sustainable Energy Solutions via First-Principles Calculations

Mg3Sb2-based materials, part of the Zintl compound family, are known for their low thermal conductivity but face challenges in thermoelectric applications due to their low energy conversion efficiency. This study addressed these limitations through first-principles calculations using the CASTEP module in Materials Studio 8.0, aiming to enhance the thermoelectric performance of Mg3Sb2 via strategic doping. Density functional theory (DFT) calculations were performed to analyze electronic properties, including band structure and density of states (D.O.S.), providing insights into the influence of various dopants. The semiclassical Boltzmann transport theory, implemented in BoltzTrap (version 1.2.5), was used to evaluate key thermoelectric properties such as the Seebeck coefficient, electrical conductivity, electronic thermal conductivity, and electronic figure of merit (eZT). The results indicate that doping significantly improved the thermoelectric properties of Mg3Sb2, facilitating a transition from p-type to n-type behavior. Bi doping reduced the band gap from 0.401 eV to 0.144 eV, increasing carrier concentration and mobility, resulting in an electrical conductivity of 1.66 × 106 S/m and an eZT of 0.757. Ge doping increased the Seebeck coefficient to −392.1 μV/K at 300 K and reduced the band gap to 0.09 eV, achieving an electronic ZT of 0.859 with low thermal conductivity (11 W/mK). Si doping enhanced stability and achieved an electrical conductivity of 1.627 × 106 S/m with an electronic thermal conductivity of 11.3 W/mK, improving thermoelectric performance. These findings established the potential of doped Mg3Sb2 as a highly efficient thermoelectric material, paving the way for future research and applications in sustainable energy solutions.

Flecainide acetate inhalation solution for cardioversion of recent-onset, symptomatic atrial fibrillation: results of the phase 3 RESTORE-1 trial

Abstract Introduction Safe, rapid, and efficacious drugs for acute cardioversion of paroxysmal AF (PAF) are needed. In an open-label, Phase 2 study (INSTANT), orally inhaled flecainide was safe and efficacious for acute conversion of PAF to sinus rhythm (SR).[1, 2] Purpose Evaluate the efficacy and safety of flecainide acetate inhalation solution (FlecIH-103) compared to placebo in patients with short-duration, symptomatic, newly diagnosed, or recurrent PAF. Methods RESTORE-1 was a multicentre, randomized, double-blind, placebo-controlled trial in patients with symptomatic PAF (≤48 hours). Patients received FlecIH-103 at an estimated total lung dose of 120 mg or placebo (3:1) over 8 minutes using a breath-actuated nebulizer and were continuously monitored for 90 minutes (observation period), using a single-lead patch ECG electrode. Results The study was stopped prematurely after 55 of the expected 400 patients had been enrolled due to lower-than-expected flecainide peak plasma levels (197.8 ng/mL; 1.85-fold lower than those observed with the same target dose in INSTANT) and modest efficacy. The Data Monitoring Committee confirmed that there were no safety risks. Fifty-four of the enrolled patients (42 active; 12 placebo) were in AF at the start of inhalation. Baseline characteristics were well-balanced between treatment groups; overall mean age was 59.6 years (SD: 13.5) and 31.5% of patients were female. Cardioversion rates during the observation period in the efficacy population (n=51; 39 active, 12 placebo) were 30.8% (95% CI: 18.5-46.5%) in the active group and 0% (95% CI: 0.0-28.2%) in the placebo group (p=0.04; figure 1). In the active group, the median time to conversion from start of inhalation was 12.8 minutes (IQR: 7.8-25.0 minutes), which includes an 8-minute inhalation period. Among the 12 patients whose AF converted to SR, only 1 (8.3%) still had AF-related symptoms compared to 71.8% of patients whose AF did not convert to SR (p<0.001). Time to discharge-eligible status was 1.6h for patients whose AF cardioverted and 3.3h for those whose AF did not (p=0.002; figure 2). The most common adverse events (AEs; ≥8%) occurring more frequently in the active than the placebo group were the following: dyspnoea (14.3%), dysgeusia (14.3%) and cough (11.9%). No serious AEs or cardiovascular events of special interest (hypotension, ventricular tachycardia, bradycardia, sinus pause, atrial flutter 1:1, other arrhythmias) were reported. Conclusions Orally inhaled flecainide, at approximately half of the targeted dose, was modestly effective and safe. The 1.5-fold lower conversion rate observed in this study, compared to the same dose in the INSTANT trial, is consistent with the lower plasma levels of flecainide achieved. Future studies will be designed to improve drug delivery to yield peak plasma levels of flecainide associated with higher conversion rates.

Effect of copepod Apocyclops dengizicus addition on growth, survival, and proximate composition of Macrobrachium rosenbergii postlarvae cultured in brackish‐water biofloc system

AbstractObjectiveThe effects of periodically adding the cyclopoid copepod Apocyclops dengizicus (every 4 days at a rate of 4 individuals/mL) with biofloc technology (BFT‐C) was compared with conventional biofloc technology (BFT; without copepod) or a clear‐water control for Macrobrachium rosenbergii postlarvae nursery culture.MethodsSurvival, growth, proximate composition, and economics of SMacrobrachium rosenbergii postlarvae was calculated. Water quality and biofloc proximate composition were also measured among treatments. For the BFT, maize starch was applied to achieve a C:N ratio of 20:1. Triplicate 125‐L polyethylene tanks containing 500 postlarvae each (9.40 ± 1.88 mg) were evaluated.ResultSpecific growth rate was significantly greater in the BFT‐C group (8.40 ± 0.24% per day) than BFT (7.23 ± 0.21% per day) and control (7.12 ± 0.42% per day) groups. Postlarvae survival was significantly increased with the BFT‐C (94.46%) treatment compared with the BFT (87.33%) and control (82.60%). A significantly lower food conversion ratio (1.08) was obtained in BFT‐C than both the BFT (1.73) and control (1.90), possibly due to significantly higher biofloc crude protein and lipid contents in the BFT‐C than BFT. Postlarvae whole‐body protein and lipid contents were significantly elevated in BFT‐C compared to the BFT and control treatments. Economics of gross return, net return, and cost‐benefit ratio were significantly better at BFT‐C than in either the BFT or control groups.ConclusionThis study indicates that copepod additions with BFT enhanced prawn postlarvae survival, growth, and whole body protein and lipid, as well as economics, which could augment productivity and sustainability in this industry.

Techno-economic assessment of modified Fischer-Tropsch synthesis process for direct CO2 conversion into jet fuel

Direct use of CO2 through modified Fischer-Tropsch synthesis (FTS) process presents a viable approach for the production of carbon–neutral jet fuel. However, achieving high performance for the CO2-FTS process remains a significant challenge. Current technology can only achieve low CO2 conversion and low jet fuel yield using tailored catalysts, which hinders the commercial deployment of direct CO2-FTS process. This paper presents a techno-economic assessment (TEA) of jet fuel production via CO2-FTS process at commercial-scale. Two ex-situ water removal configurations: (a) multi-stage CO2-FTS process and (b) CO2-FTS with tail gas recycle process were conducted to assess their potential for performance improvement. Process performance was evaluated using a model developed in Aspen Plus® linking with Aspen Custom Modeller® (ACM), while economic evaluation was carried out in Aspen Process Economic Analyzer®. The CO2-FTS model was based on first principles and modified Anderson-Schulz-Flory (ASF) distribution. Results indicated that both ex-situ water removal configurations can significantly improve the process performance. CO2-FTS process with 90% tail gas recycle has the best performance for both technical and economic analysis. The process achieved 85.8% CO2 conversion and 35.6% jet fuel yield with the lowest energy demand of 4.57 MWh per tonne of produced jet fuel. Moreover, it boasts the lowest minimum selling price (MSP) of jet fuel at US$2.6/kg despite incurring the second-highest capital expenditure cost of M$ 451.3. A comparison of the two ex-situ water removal configurations at 61.9% and 76.5% CO2 conversion, suggests that both processes exhibit comparable technical performances, yet the recycling of tail gas holds the potential to reduce economic costs. Consequently, this study will inspire researchers on process improvement and cost reduction of the commercial-scale CO2-FTS jet fuel production.

Suppressing Se Vacancies in Sb2Se3 Photocathode by In Situ Annealing with Moderate Se Vapor Pressure for Efficient Photoelectrochemical Water Splitting.

Sb2Se3 emerges as a promising material for solar energy conversion devices. Unfortunately, the common deep-level defect VSe (selenium vacancy) in Sb2Se3 results in a low solar conversion efficiency. The post selenization process has been widely adopted for suppressing VSe. However, the effect of selenization on suppressing VSe is often compromised and even more VSe are induced due to defect-correlation. Herein, high-quality Sb2Se3 films are prepared using an unconventional selenization process, with precisely regulating in situ annealing Se vapor pressure. It is found that moderate Se vapor pressure annealing can efficiently suppress VSe by overcoming defect-correlation, as well as promotes grain growth and forms a better heterojunction band alignment. Consequently, the Sb2Se3 photocathode shows a high-level photocurrent of 19.5 mA cm-2 at 0 VRHE, an onset potential of 0.40 VRHE and a half-cell solar-to-hydrogen conversion efficiency of 1.9%, owing to the inhibited charge recombination, excellent charge transport and interface charge extraction. This work provides a significant insight to suppress deep-level defect VSe by adjusting Se vapor pressure for efficient Sb2Se3 photocathode.

Optimized spacing of active sites in Ni-Mo catalysts enhances ethanol production in syngas conversion

The direct conversion of syngas to ethanol is highly attractive but remains challenging due to low CO conversion and poor EtOH/ROH. We investigated the conversion of syngas over a KNiMo2C catalyst modified with carbon dots (CDs) derived from Ligustrum lucidum leaves. On the Ni0.54Mo-A catalyst, a CO conversion of 43.4 % was achieved, with oxygenates selectivity and EtOH/ROH，reaching 48.2 % and 63.7 %, the space-time yield of ethanol was 132.5 mg/gcat/h. Comprehensive characterization revealed that CDs regulate the distance between Ni-Mo active sites, preventing excessive proximity and maintaining an optimal separation. This adjustment significantly enhances EtOH/ROH by modulating the probability of carbon chain growth. A potential new reaction pathway for directly converting syngas to ethanol is proposed, The C-C coupling of CHx* with *COOH or *CO2 is identified as a key step in carbon chain growth. This work provides a new catalytic pathway for the syngas to ethanol industry.

Synthesis of concave Au NRs-Pt-CdS plasmonic photocatalyst with efficient hydrogen production rate

Light-driven water photolysis for hydrogen (H2) generation has been proven to be exceptionally efficient in the field of energy transformation. Nevertheless, the practical applications of many single-component semiconductors still suffer from a relatively low energy conversion efficiency. In this work, concave gold nanorods (Au NRs) with three plasmon resonance modes were synthesized using a one-step method in an aqueous solution. Pt nanoparticles and CdS nanocrystals were rational grown onto Au NRs to design the plasmonic photocatalysts with specific morphology and structure characteristic. Photocatalytic test indicated that concave Au NRs-Pt-CdS hetero-nanostructure possess efficient H2 production rate under visible and near-infrared regions. These findings offer a blueprint for creating a novel group of hetero-nanostructures that combine faceted noble metal nanoparticles with semiconductor materials, demonstrating promise for applications across fields such as photocatalysis and energy storage.

Kinetic Characterization of Pt/Al2O3 Catalyst for Hydrogen Production via Methanol Aqueous-Phase Reforming

Compared to steam reforming, methanol aqueous-phase reforming (APR) converts methanol to hydrogen and carbon dioxide at lower temperatures, but also displays lower conversion rates. Herein, methanol APR is studied over the active Pt/Al2O3 catalyst under different operating conditions. Studies were conducted at different temperatures, pressures, methanol mass fractions, and residence times. APR performance was evaluated in terms of methanol conversion, hydrogen production rate, hydrogen selectivity, and by-product formation. The results revealed that an increase in operating pressure and methanol mass fraction had an adverse effect on the APR performance. Conversely, it was found that hydrogen selectivity was unaffected by the operating pressure and residence time for the methanol feed mass fraction of 5%. For the methanol feed mass fraction of 55%, hydrogen selectivity was improved by operating pressure and residence time. The alumina support phase change to boehmite as well as sintering and leaching of the catalytic particles were observed during catalyst stability experiments. Additionally, a comparison between methanol steam reforming (MSR) and APR was also performed.

Microwave-treated layered graphite for highly efficient solar-powered seawater desalination and wastewater treatment

In the midst of the global water crisis, the ‘waste-to-treasure’ strategy, which includes desalination and wastewater recycling, is proving to be a promising approach. However, existing solar evaporators are hampered by challenges such as low photothermal conversion efficiency and significant heat losses. Here, we present an innovative solution that reduces the band gap of the material and improves the efficiency of light recycling. As a result, the microwave-treated graphite achieves a 15 % reduction in reflectivity and a 9 °C increase in surface temperature. In addition, the integration of this graphite with a hydrogel to modulate the interfacial wettability further optimizes the evaporation efficiency. When exposed to sunlight, the developed cone column evaporator achieves an impressive evaporation rate of 2.91 kg m−2 h−1, which is a significant increase of 663 % over the natural evaporation rate of a 3.5 wt% NaCl solution. Remarkably, no salt deposits were observed on the surface of the evaporator during the tests and the material exhibited excellent adsorption and desorption properties for pollutants, highlighting its potential for sustainable applications. These results provide valuable theoretical and practical insights for the design and development of high-efficiency solar evaporators.