Reduction In Activity Research Articles

Annona muricata leaf extract mediated synthesis of pure and Co doped TiO2 nanoparticles: Evaluation of catalytic reduction, antimicrobial and antioxidant activities

Annona muricata leaf extract mediated synthesis of pure and Co doped TiO2 nanoparticles: Evaluation of catalytic reduction, antimicrobial and antioxidant activities

Silicalite-1 Zeolite Enables Graphitic Carbon Nitride High Selectivity toward CO2 Photoreduction

Carbon monoxide (CO) constitutes a pivotal chemical feedstock, extensively applied in diverse industrial processes such as the Fischer–Tropsch synthesis and the water-gas shift reaction, among others, underscoring its significant role in the chemical industry. Photocatalytic CO2 reduction to produce CO provides an appealing route to consume useless greenhouse gases to valuable chemical feedstock. Regarding the poor selectivity of photocatalytic CO2 conversion and the separation complexity for mixed products, integrating zeolite with semiconductor photocatalyst is first presented to achieve highly selective CO2 photoreduction. Herein, silicalite-1 zeolite with high surface area and excellent CO2 affinity is selected to construct a graphitic carbon nitride/silicalite-1 (CN/S-1) composite via a facile thermal polymerization procedure. The introduced S-1 zeolite enables extended visible light response, enhanced CO2 adsorption, promoted separation and transportation of photoexcited charge carriers for the as-synthesized CN/S-1 composite. The resulting CN/S-1 composite shows significantly improved photocatalytic CO2 reduction activity, yielding CO and CH4 of 452.8 and 11.63 μmol·h-1, respectively. The CO selectivity of the CN/S-1 composite achieves 97.5%, which is maximal so far among the CN-based photocatalysts. In-situ Fourier transformed infrared (in-situ FTIR) spectra characterization reveals the composite prefer to dissociate COOH* to CO upon the incorporation of S-1 zeolite rather than protonation into hydrogenation products.

Enhanced Activity and Stability for Electrocatalytic Nitrate Reduction to Ammonia over Low-Coordinated Cobalt.

It is still challenging to develop an effective strategy to simultaneously enhance the activity and stability of electrocatalysts for electrocatalytic nitrate reduction reaction (eNO3RR). Herein, taking metallic cobalt as an example, it is demonstrated that the construction of low-coordinated cobalt nanosheets (L-Co NSs) by H2 plasma etching of electrodeposited cobalt nanosheets (Co NSs) can greatly enhance the activity and stability of metallic cobalt for eNO3RR. Compared with Co NSs, at -0.4V versus RHE, the nitrate removal rate, ammonia partial current density, and ammonia yield are increased by L-Co NSs from 82.14% to 98.57%, from 476 to 683mA cm-2, and from 2.11 to 2.54mmol h-1 cm-2, respectively. In addition, L-Co NSs demonstrate negligible activity decay after 30 cycles of stability test, while the Co NSs show significant activity decline. In situ electrochemical characterizations and theoretical calculations verify that the abundance of Co vacancies in L-Co NSs not only contribute to the optimized electronic structure and enhanced desorption of key intermediate to boost the activity but also facilitate the transformation of Co(OH)2 to Co0 to promote the stability. Furthermore, L-Co NSs exhibit favorable performance in removing nitrate from simulated wastewater and air plasma discharge-electrocatalytic reduction cascade system to produce ammonia.

Transient pulsed discharge preparation of graphene aerogel supports asymmetric Cu cluster catalysts promote CO2 electroreduction

Designing asymmetrical structures is an effective strategy to optimize metallic catalysts for electrochemical carbon dioxide reduction reactions. Herein, we demonstrate a transient pulsed discharge method for instantaneously constructing graphene-aerogel supports asymmetric copper nanocluster catalysts. This process induces the convergence of copper atoms decomposed by copper chloride onto graphene originating from the intense current pulse and high temperature. The catalysts exhibit asymmetrical atomic and electronic structures due to lattice distortion and oxygen doping of copper clusters. In carbon dioxide reduction reaction, the selectivity and activity for ethanol production are enhanced by the asymmetric structure and abundance of active sites on catalysts, achieving a Faradaic efficiency of 75.3% for ethanol and 90.5% for multicarbon products at −1.1 V vs. reversible hydrogen electrode. Moreover, the strong interactions between copper nanoclusters and graphene-aerogel support confer notable long-term stability. We elucidate the key reaction intermediates and mechanisms on Cu4O-Cu/C2O1 moieties through in situ testing and density functional theory calculations. This study provides an innovative approach to balancing activity and stability in asymmetric-structure catalysts for energy conversion.

Lifestyle risk reduction engagement during interconception: a qualitative descriptive study of women’s preferences

BackgroundPrevention and self-management of lifestyle risks can reduce non-communicable disease risks and improve the health of mothers and their children. We explored Australian women’s preferences for lifestyle risk reduction engagement...

Microbes-Assisted Arsenate Reduction Activity in Bangladesh Drinking Water Wells [Letter]

Microbes-Assisted Arsenate Reduction Activity in Bangladesh Drinking Water Wells [Letter]

Ce1-xMnxVO4 with Improved Activity for Low-Temperature Catalytic Reduction of NO with NH3.

Novel Ce1-xMnxVO4 catalysts prepared via modified hydrothermal synthesis were used in selective catalytic reduction of NO using NH3 (NH3-SCR). The Ce1-xMnxVO4 catalysts displayed optimum NO removal efficiency at 250 oC. Physicochemical properties including crystal type, morphology, particle size, elemental composition, BET surface area, chemical bond, and valence state were studied by XRD, TEM, EDS, N2 adsorption-desorption, Raman spectroscopy, and XPS. Specific properties such as reduction property and acid sites were studied by H2-TPR and NH3-TPD. The in-situ DRIFTS results revealed that NH3-SCR over Ce0.5Mn0.5VO4 follows the Eley-Rideal mechanism. The experimental results showed that doped "active manganese" replaces the Ce position in CeVO4. The Mn-O-Ce interaction may increase the contents of defective oxygen and Brønsted acid sites, thus leading to enhanced activity.

Internet-Based Dementia Prevention Intervention (DementiaRisk): Protocol for a Randomized Controlled Trial and Knowledge Translation.

Research has shown that engaging in a range of healthy lifestyles or behavioral factors can help reduce the risk of developing dementia. Improved knowledge of modifiable risk factors for dementia may help engage people to reduce their risk, with beneficial impacts on individual and public health. Moreover, many guidelines emphasize the importance of providing education and web-based resources for dementia prevention. Internet-based interventions may be effective, but few have been studied rigorously or widely disseminated. We created DementiaRisk, an award-winning, web- and email-based education platform for the public focused on modifiable risk factors, featuring multimedia e-learning and email "microlearning" content, to help raise awareness and improve knowledge of actions to reduce dementia risk. This protocol describes a randomized controlled trial to (1) evaluate whether exposure to DementiaRisk changes knowledge of dementia risk factors, intention to engage in risk reduction activities, and health behaviors related to dementia risk reduction and to (2) explore qualitative aspects including participants' engagement and satisfaction with the intervention and barriers and facilitators to use. Using a sequential explanatory mixed methods design, this study conducts a quantitative analysis followed by a qualitative inquiry to evaluate outcomes and feasibility. In total, 485 participants will be recruited on the web and randomly assigned to 2 groups: one accessing DementiaRisk and the other receiving alternative e-learning on mild cognitive impairment. Assessments will be delivered on the web at baseline (T1), at 4 weeks (T2), and at 2 months after the intervention (T3). Knowledge will be assessed using items from the Dementia Knowledge Assessment Scale, intentions to engage in risk reduction activities will be assessed using items in line with current evidence, and health behaviors related to dementia risk reduction will be assessed using items from the Godin-Shephard Leisure Time Physical Activity Questionnaire along with additional questions related to a range of health status domains. Outcomes and feasibility will be assessed using the Information Assessment Method for patients and consumers. A linear mixed effects model will be used to examine the relationship between each outcome score by group and time point. This study was approved by the Hamilton Integrated Research Ethics Board on August 24, 2022 (project ID 14886) and received funding in February 2023. Recruitment took place from March 28, 2023, to April 28, 2023, with the final participants completing the intervention by August 18, 2023. Analyses and interpretation of data are ongoing. DementiaRisk is a readily scalable, technology-enhanced solution for dementia prevention education. It has been designed using evidence-based principles of multimedia learning. It has the potential to scale and spread widely using the open internet, so it may be able to reach a wider audience than traditional in-person educational interventions. ClinicalTrials.gov NCT05383118; https://clinicaltrials.gov/study/NCT05383118. DERR1-10.2196/64718.

Quantifying Asymmetric Coordination to Correlate Oxygen Reduction Activity in Fe‐Based Single‐Atom Catalysts

Quantifying Asymmetric Coordination to Correlate Oxygen Reduction Activity in Fe‐Based Single‐Atom Catalysts

Quantifying Asymmetric Coordination to Correlate Oxygen Reduction Activity in Fe-Based Single-Atom Catalysts.

Precisely manipulating asymmetric coordination configurations and examining electronic effects enable to tuning the intrinsic oxygen reduction reaction (ORR) activity of single-atom catalysts (SACs). However, the shortage of a definite relationship between coordination asymmetry and catalytic activity makes the rational design of SACs ambiguous. Here, we propose a concept of "asymmetry degree" to quantify asymmetric coordination configurations and assess the effectiveness of active moieties in Fe-based SACs. A theoretical framework is established where elucidating the volcanic relationship between asymmetry degree and ORR activity by constructing a series of Fe-based SAC models doped with non-metal atoms (B, P, S, Se, and Te) in the first or second coordination sphere, which aligns with Sabatier principle. The predicted ORR activity of Fe asymmetric active moieties is then experimentally validated using asymmetry degree. The combined computational and experimental results suggest that single-atom moiety with a moderate asymmetry degree exhibits optimal intrinsic ORR activity, because breaking the square-planar symmetry of FeN4 can alter the electronic population of the Fe 3d-orbital, thereby optimizing the adsorption-desorption strength of intermediates and thus enhancing the intrinsic ORR activity. This fundamental understanding of catalytic activity from geometric and electronic aspects offers a rational guidance to design high-performance SACs with asymmetric configurations.

Compact Disc-Derived Nanocarbon-Supported Catalysts with Extreme Catalytic Activity.

Advanced carbon-metal hybrid materials with controllable electronic and optical properties, as well as chemical reactivities, have attracted significant attention for emerging applications, including energy conversion and storage, catalysis and environmental protection. However, the commercialization of these materials is hampered by several vital problems, including energy-intensive synthesis and expensive chemicals, and inefficient control of their structures and properties. Herein, we report the simple and controllable engineering of nanocarbon-metal self-assembled silver nanocatalysts (SSNs) derived from polycarbonate (PC)-based optical discs using microplasmas under ambient conditions. The plasma-engineered catalysts exhibited controlled properties including surface functionalities, hydrophilicities, Ag+/Ag0 metallic states, and Ag loading. The synthesized catalysts leverage localized surface plasmon resonance (LSPR) properties, enabling enhanced catalytic activity for the rapid reduction of carcinogenic 4-nitrophenol (4-NP) to the valuable pharmaceutical intermediate 4-aminophenol (4-AP), achieving a high reaction rate constant of 0.2 ± 0.0 s-1 and completing the reduction in just 30 s. Demonstrating robust performance, the SSNs maintained up to 90% conversion efficiency after ten recycling cycles, underscoring their stability and reusability. This work not only presents an effective approach to upcycling optical disc waste, but also highlights the potential of plasma-engineered nanocatalysts in environmental remediation, offering a low-energy solution for high-efficiency pollutant reduction.

A Versatile Self‐Templating Approach for Constructing Ternary Halide Perovskite Heterojunctions to Achieve Concurrent Enhancement in Photocatalytic CO2 Reduction Activity and Stability

AbstractMetal halide perovskite (MHP)‐based photocatalysts encounter significant stability challenges in water‐containing systems, posing a major obstacle to their application in artificial photosynthesis. Herein, an innovative and universal strategy is present to create MHP‐based ternary heterojunctions based on a self‐templating method. A series of composite catalysts featuring sandwich hollow structures are constructed, with MHPs such as CsPbBr3, Cs3Bi2I9, Cs3Sb2Br9, and Cs2AgBiBr6 serving as the intermediate layers. The unique sandwich structure effectively shields MHPs from direct water contact, allowing MHP‐based photocatalysts to exhibit exceptional stability in water‐containing photocatalytic environments for durations exceeding 200 h. Furthermore, the hollow design ensures complete contact between the reaction substrates with both the oxidation and reduction functional areas. Compared to single perovskite materials, MHP‐based ternary heterojunction photocatalysts exhibit stronger oxidation capability and improved charge separation efficiency, leading to a substantial enhancement in photocatalytic CO2 reduction performance. Notably, the ternary heterojunction with CsPbBr3 as the intermediate layer achieves an electron consumption rate of up to 1824 µmol g−1 h−1 for CO2 reduction, which is far superior to other reported MHP‐based catalysts under similar conditions. This study provides a potent strategy for simultaneously enhancing the stability and activity of MHP‐based photocatalysts, paving the way for their potential applications in artificial photosynthesis.

Enhancing the Electrochemical Oxygen Reduction Activity of PPy-Derived Porous Carbon through a Facile Ternary Doping Approach

Enhancing the Electrochemical Oxygen Reduction Activity of PPy-Derived Porous Carbon through a Facile Ternary Doping Approach

Equity financing for carbon emission reduction supported by platform retailer: bane or boon for supplier encroachment?

This study examines a low-carbon supply chain consisting of a capital-constrained supplier and a platform retailer that links the supplier and consumers directly in addition to reselling products. The retailer facilitates the supplier in raising the green value of products by fully investing in carbon emission reduction activities, while the supplier chooses whether to encroach on the retailer. Using game theory, we examine the relationship between the supplier's encroachment decision and the retailer's investment plan for reducing carbon emissions. Then, we analyze the equilibrium profits of the firms under different carbon emission reduction investment strategies and discover that, in multiple instances, the retailer gains from the supplier encroachment. The advantage stems from the revenue through the direct selling channel in addition to the decrease in the double marginalisation. The retailer's carbon emission reduction investment has a cost-sharing effect, alleviating the intrusion burden on the supplier. The findings suggest that a retailer may not necessarily aim to prevent supplier encroachment through the investment in carbon emission reduction activities. A supplier with limited capital may be induced to encroach on the retailer with such an investment in certain instances. Finally, managerial implications are examined and presented.

Enzyme-Inspired Single Selenium Site for Selective Oxygen Reduction.

Learning from nature has garnered significant attention in the scientific community for its potential to inspire creative solutions in material or catalyst design. The study reports a biomimetic single selenium (Se) site-modified carbon (C) moiety that retains the unique reactivity of selenoenzyme with peroxides, aiming to selectively catalyze the oxygen reduction reaction (ORR). The as-designed Se-C demonstrates nearly 100% 4-electron selectivity, evidenced by 0.039% of H2O2 yield at 0.5 V versus reversible hydrogen electrode, outperforming commercial platinum (Pt) by 65 times. In-situ X-ray absorption spectroscopy and theoretical calculations attribute this exceptional selectivity to the enzyme-like behaviors of the Se site to steal an O atom from peroxide intermediates. The second achievement is the significantly increased consecutive 2+2 electron selectivity. Benefiting from the enzyme-like H2O2 reduction activity with a higher onset potential of 0.915 V compared to Pt at 0.875 V, the Se-C as a secondary catalytic site reduced the H2O2 yields of the Co-N-C, Fe-N-C, and N-C catalysts by 96%, 67%, and 98%, respectively, via a consecutive 2+2 electron pathway. This also leads to more stable catalysts via protecting the active sites from oxidative attacks. This work establishes new pathways for precise tuning of reaction selectivity in ORR and beyond.

Optimizing the electronic synergy of atomically dispersed dual-metal sites for high-efficiency oxygen evolution/reduction reaction.

We reported an exogenous nitrogen-doped method to synthesize a bifunctional electrocatalyst with oxygen reduction and evolution reaction activity. This electrocatalyst displays excellent ORR (E1/2 = 0.9 V vs. RHE) and OER (potential E = 1.57 V at 10 mA cm-2) activity.

Impact of a community-based lifestyle intervention with initial sedentary reduction or physical activity increasing goals on self-reported health-related quality of life.

In previous efforts, health-related quality of life (HRQoL) improved for individuals at high risk of type 2 diabetes and cardiovascular disease after participation in community-based lifestyle interventions (LI) with a moderate-to-vigorous physical activity (MVPA) movement goal. It is unknown whether HRQoL improves with LI when the primary movement goal is to reduce sedentary behavior. HRQoL changes were examined among adults with overweight and prediabetes and/or metabolic syndrome randomized to a 12-month Diabetes Prevention Program-based Group Lifestyle Balance (DPP-GLB) community LI work with goals of weight-loss and either increasing MVPA (DPP-GLB) or reducing sedentary time (GLB-SED). Study participants (N = 269) completed the Euroqol 5 dimension 3 long (EQ5D-3L index and EuroQol Visual Analog Scale (EQVAS)-visual analog scale) at baseline, and 6 and 12 months. Paired t-tests were used to evaluate pre-to-post-intervention changes by arm. Mean EQVAS improvements for the GLB-SED arm at 6 and 12 months were +5.6 (SE = 1.3; P < .0001) and +4.6 (SE = 1.4; P = .0006), respectively. Similar mean EQVAS improvements were reported for the DPP-GLB arm; +5.9 (SE = 1.2; P < .0001) and +4.9 (SE = 1.2; P = .0001) at 6 and 12 months, respectively. Mean EQ5D index improvements were significant in the GLB-SED arm [6 months: +0.03 (SE = 0.01; P = .004); and 12 months: +0.04 (SE = 0.01; P = .006)], but not in the DPP-GLB arm. Participation in community LI with a primary movement goal to reduce sedentary behavior improved HRQoL at least as well as traditional LI focused more on MVPA improvement, supporting an alternate intervention strategy for those who can't or won't engage in MVPA as the primary movement goal.

Plasmon-Enhanced CO2 Reduction to Liquid Fuel via Modified UiO-66 Photocatalysts

Metal–organic frameworks (MOFs) have emerged as versatile materials with remarkably high surface areas and tunable properties, attracting significant attention for various applications. In this work, the modification of a UiO-66 MOF with metal nanoparticles (NPs) is investigated for the purpose of enhancing its photocatalytic activity for CO2 reduction to liquid fuels. Several NPs (Au, Cu, Ag, Pd, Pt, and Ni) were loaded into the UiO-66 framework and employed as photocatalysts. The synergistic effects of plasmonic resonance and MOF characteristics were investigated to improve photocatalytic performance. The synthesized materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), confirming the successful integration of metal NPs onto the UiO-66 framework. Morphological analysis revealed distinct distributions and sizes of NPs on the UiO-66 surface for different metals. Photocatalytic CO2 reduction experiments demonstrated enhanced activity of plasmonic MOFs, yielding methanol and ethanol. The findings revealed by this study provide valuable insights into tailoring MOFs for improved photocatalytic applications through the incorporation of plasmonic metal nanoparticles.

A Two‐in‐One Strategy to Simultaneously Boost the Site Density and Turnover Frequency of Fe−N−C Oxygen Reduction Catalysts

Site density and turnover frequency are the two fundamental kinetic descriptors that determine the oxygen reduction activity of iron‐nitrogen‐carbon (Fe−N−C) catalysts. However, it remains a grand challenge to simultaneously optimize these two parameters in a single Fe−N−C catalyst. Here we show that treating a typical Fe−N−C catalyst with ammonium iodine (NH4I) vapor via a one‐step chemical vapor deposition process not only increases the surface area and porosity of the catalyst (and thus enhanced exposure of active sites) via the etching effect of the in‐situ released NH3, but also regulates the electronic structure of the Fe−N4 moieties by the iodine dopants incorporated into the carbon matrix. As a result, the NH4I‐treated Fe−N−C catalyst possesses both high values in the site density of 2.15×1019 sites g−1 (×2 enhancement compared to the untreated counterpart) and turnover frequency of 3.71 electrons site−1 s−1 (×3 enhancement) that correspond to a high mass activity of 12.78 A g−1, as determined by in‐situ nitrite stripping technique. Moreover, this catalyst exhibits an excellent oxygen reduction activity in base with a half‐wave potential (E1/2) of 0.924 V and acceptable activity in acid with E1/2 = 0.795 V, and superior power density of 249.1 mW cm−2 in zinc‐air batteries.

An Adsorbent for Efficient and Rapid Gold Recovery from Solution: Adsorption Properties and Mechanisms.

Adsorption is an efficient and highly selective method for gold recovery. Introducing rich N/S organic groups to combine with metal-organic frameworks (MOFs) as adsorbents is regarded as a practical and efficient approach to enhance gold recovery. Herein, a MOF (zirconium isothiocyanatobenzenedicarboxylate MOF, UiO-66-NCS) was designed to combine with amidinothiourea (AT) to form UiO-66-AT (zirconium amidothiourea-benzenedicarboxylate MOF) for efficient and rapid adsorption. The prepared UiO-66-AT delivers an improved adsorption capacity (about 903.02 mg/g at 1000 mg·L-1 of the initial Au3+) and an impressive adsorption rate within minutes (about 10 min for 200 mg·L-1 Au3+). Meanwhile, it exhibits sustainable stability after 5 cycles with a retention rate of 99.52% and excellent adsorption selectivity of 98.76% in actual wastewater. According to advanced characterizations and Density Functional Theory (DFT) simulation, the mechanism might be elaborated as electrostatic adsorption, chelating coordination, and chemical reduction. The modified active groups of the MOF provide the adsorption sites for Au(III) and the rapid reduction of Au(0). UiO-66-AT maintains a large adsorption capacity and high surface reduction activity while realizing stable application in multiple cycles, which is of good practical application value.