Difference In Reduction Potential Research Articles

Stabilization of Lattice Oxygen Evolution Reactions in Oxophilic Ce-Mediated Bi/BiCeO1.8H Electrocatalysts for Efficient Anion Exchange Membrane Water Electrolyzers.

The lattice oxygen mechanism (LOM) offers an efficient reaction pathway for oxygen evolution reactions (OERs) in energy storage and conversion systems. Owing to the involvement of active lattice oxygen enhancing electrochemical activity, addressing the structural and electrochemical stabilities of LOM materials is crucial. Herein, a heterostructure (Bi/BiCeO1.8H) containing abundant under-coordinated oxygen atoms having oxygen nonbonding states is synthesized by a simple electrochemical deposition method. Given the difference in reduction potentials between Bi and Ce, partially reduced Bi nanoparticles and surrounding under-coordinated oxygen atoms are generated in BiCeO1.8H. It is found that the lattice oxygen can be activated as a reactant of the OER when the valence state of Bi increases to Bi5+, leading to increased metal-oxygen covalency and that the oxophilic Ce3+/4+ redox couple can maintain the Bi nanoparticles and surrounding under-coordinated oxygen atoms by preventing over-oxidation of Bi. The anion exchange membrane water electrolyzer with Bi/BiCeO1.8H exhibits a low cell voltage of 1.79 V even at a high practical current density of 1.0 A cm-2. Furthermore, the cell performance remains significantly stable over 100 h with only a 2.2% increase in the initial cell voltage, demonstrating sustainable lattice oxygen redox.

Atomic Ordering Engineering of Precious Metal Alloys in Liquid Phase Synthesis.

Atomic ordering of noble metal alloys is an effective strategy for improving catalytic performance, yet the low-temperature synthesis of ordered alloys still faces significant challenges. The low-temperature liquid phase method has enormous potential for the synthesis of alloys; however, the atomic ordering mechanism of this process has not been thoroughly studied. Herein, we investigate the mechanism of the influence of metal precursors, reducing agents, solvents, and mixing modes of reactant regulating strategies on precious metal alloy ordering using this method. These regulating strategies are designed to change the coordination structure of metal complexes, affect the reduction potential of metals, and thus change the reduction order of metals and their arrangement in the alloy products. Notably, the reduction potential differences between metal complexes can be used to predict the ordering of the synthetic products (Pd-Cu, Pd-Cd, Pd-Sn, Pd-Pb, and Pt-Sn). This work provides an excellent platform for investigating atomic arrangement engineering.

Galvanic replacement-induced preparation of bloom-like Pt23Ni77 for methanol coupled efficient hydrogen production.

Galvanic replacement reaction (GRR) leverages the difference in metal reduction potentials to regulate the structure of nanomaterials. The crucial aspect of constructing highly active catalysts lies in the precise manipulation of both the oxidative dissolution of sacrificial template metals and reductive deposition of alternate metals. Herein, we investigated the morphological transformation of metal Ni as a sacrificial template in the presence of different amounts of H2PtCl6 solution and the Pt4+ substitution of Ni to achieve the redistribution of elements on the catalyst surface, which provides superior performance in both the methanol oxidation reaction (MOR) and hydrogen evolution reaction (HER). The uniform distribution of Pt on a three-dimensional transition metal Ni substrate allows for the complete exposure of the noble metal to the catalyst surface. This distribution increases the reaction area, facilitating easy access for reactants and promoting electron transfer. Meanwhile, Pt (1.39 Å) has a larger atomic radius compared to Ni (1.24 Å), and the substitution reaction in the transition metal phase induces strong compressive strain, which effectively regulates the electronic structure of Ni.

Trash to Treasure: Recovery of Trace Platinum from Industrial Process Solutions

Concerns about metal scarcity are becoming more prevalent due to the depletion of the world’s natural resources and increased demand of metal productions. Therefore, more efficient and innovative methods for metal recovery are required. Among the traditional hydrometallurgical methods [1], the electrochemical recovery of metals - like electrowinning - provide a state-of-the-art basis for sustainable metals recovery through the use of renewable electricity. In electrowinning, the metals are recovered by electrodeposition from concentrated and purified leaching solutions. Nevertheless, the process solutions in the final stages of hydrometallurgical or pyro-hydrometallurgical operations still contain precious metals Ag, Au, and platinum group metals at very low concentrations (< mg L-1 or < μg L-1). For example, platinum - a critical element in photocatalysts for the hydrogen economy, electronics and medical applications – can also be recovered from such trace concentrations to prevent both material loss and to provide additional value. Recently, electrodeposition and redox replacement (EDRR) - method has been applied for selective precious metal recovery from lower-grade raw materials-hydrometallurgical process solutions [2]. During EDRR, a sacrificial metal with less nobility is first deposited through electrodeposition, then the precious metal is recovered onto the electrode surface through RR reaction, driven by the difference in reduction potentials between the two metals. EDRR can be tailored through operational parameter selection, thereby allowing an optimized purity of recovered metals and even controllable preparation of metal coatings, nanoparticles, high-value-added functional surfaces (photocatalyst, corrosion resistant) directly from industrial process solutions [2].In the course of previous studies, it has been observed that metal reduction may also occur via aqueous reduction close to the electrode surface [3]. If actual electrodeposition of sacrificial species into metallic form is not indispensable before the metal recovery in the RR step, process with lower energy consumption and higher purity end-product may be realized via aqueous reduction (EAR). In the current study, multivalent iron was selected as reductive species during EAR-process to recover dissolved platinum. Specifically, dissolved Fe(III) in chloride-based media is first electrochemically reduced to a lower oxidation state Fe(II), then in the RR step, the produced aqueous Fe(II) species serve as reductant to trigger the consequent deposition of Pt on the electrode. As a result, the EAR method succeeded in recovering platinum on the electrode. Chloride concentration was shown to have a substantial impact on the platinum recovery, in terms of both recovery efficiency and structure of deposits, which is suggested to be derived from the Fe and Pt complexation in chloride-based media. The recovery of Pt based on EAR also varies with EAR process parameters, e.g., the applied potential and time to reduce Fe(III), or RR time. The influence of other species (concentrations) and the pH in solution were systematically studied as well, further paving the way to apply EAR method in other metal recovery system. Acknowledgements This work was supported by the Academy of Finland project EARMetal (LC, KY, ML: 339979 and LC, KY, JV: 342080). The RawMatTERS Finland Infrastructure (RAMI) funded by the Academy of Finland and based at Aalto University is also acknowledged. Reference [1] M.E. Wadsworth, J.D. Miller, Hydrometallurgical Processes. In: H.Y. Sohn, M.E. Wadsworth (Eds), Rate Processes of Extractive Metallurgy, Springer, Boston, 1979. https://doi.org/10.1007/978-1-4684-9117-3_4[2] L. Cui, K. Yliniemi, J. Vapaavuori, M. Lundström,Recent developments of electrodeposition-redox replacement in metal recovery and functional materials: A review, Chem Eng J. (2023). https://doi.org/10.1016/j.cej.2023.142737 [3] I. Korolev, S. Spathariotis, K. Yliniemi, B.P. Wilson, A.P. Abbott, M. Lundström, Mechanism of selective gold extraction from multi-metal chloride solutions by electrodeposition-redox replacement, Green Chem. 22 (2020) 3615–3625. https://doi.org/10.1039/D0GC00985G

Spatial differentiation of carbon emissions reduction potential for construction and demolition waste recycling.

Identifying the regional differences and drivers for carbon reduction of construction and demolition waste (C&DW) recycling is essential to combat climate change. This study aims to calculate the carbon reduction potential for C&DW recycling from 2006 to 2021 in China and investigates the spatial differences and driving factors of carbon reduction potential for C&DW waste by combining the Theil index, Gini coefficient, and geographic detector methods. The carbon reduction potential for C&DW recycling in China was "high in the east and low in the west" overall level, with an average annual growth rate of 6.27%. The overall differences in carbon reduction potential for C&DW recycling are decreasing, mainly due to intraregional differences and inter-provincial differences in Northeast China. The population size, urbanization rate, and technological effect are the key factors influencing carbon reduction potential for C&DW recycling. There are two types of interactions between influencing factor pairs: nonlinear enhancement and two-factor enhancement. This study's results can guide policymakers to devise relevant, regionally specific policies.

Flexible and Printable Composite Ink for Thermal Management of Soft Electronics

AbstractSince heat generation in electronic devices causes thermal failure, heat dissipation is of critical importance. Furthermore, deformable devices are subjected to mechanical stress, therefore, mechanically stable thermal management material should be considered. Herein, a strategy for printable, thermally conductive, and mechanically stable composite ink for thermal management is introduced. Based on the galvanic replacement between eutectic gallium indium (EGaIn) nanoparticles and silver (Ag) flakes, decoration of the EGaIn nanoparticles on Ag flakes is resulted from the difference in standard reduction potential between Ag, Ga, and In. The resultant alloy formation(Ag–Ga or Ag–In) serves as the thermal transport junction between Ag flakes, leading to high thermal and electrical conductivity (≈140 W mK−1 and ≈106 S m−1, respectively). In addition, owing to the polymer binder, the printed ink is mechanically stable on a substrate exhibiting stable thermal conductivity and sheet resistance under the cyclic bending test. Notably, the heat dissipation of the light‐emitting diode (LED) showed better performance when applied with the developed composite ink compared to commercial Ag paste and thermal paste. The junction temperature of the LED is reduced effectively, resulting in a longer lifetime of the LED. The thermal management solution can be utilized in next‐generation soft electronics.

Galvanically Replaced Au/Ag Nanostructures as a SERS‐Active Substrate with Progressive Interior Hotspots

AbstractInterior hotspots in surface‐enhanced Raman spectroscopy (SERS) platforms have attracted intensive attention because they enable facile methodologies and exhibit excellent sensing behavior. Molecules surrounded by plasmonic materials exhibit dual functions as field‐confined regions and analytes, and their domain consistency eventually triggers the amplification of SERS signals. In this study, to conveniently realize interior hotspots, hollow regions such as voids and interstitials are strategically introduced via a galvanic reaction (GR) as a result of the difference in reduction potential between Au and Ag. The imbalanced stoichiometric ratio and diffusion fluxes induce the Kirkendall effect in conjunction with the GR between Au and Ag. SERS platforms with narrow and densified interior hotspots are optimized by controlling the reaction time. The activation of interior hotspots is confirmed using the finite‐difference time‐domain method, which indicates a theoretical enhancement factor of 1.07 × 107 based on a fourth‐power approximation. The spontaneous GR reaction enables sensing operation with high reproducibility (relative standard deviation of &lt;10%). The proposed bimetallic platforms are used to trace methylene blue and rhodamine 6G dyes until their concentrations reach 50 nm. Therefore, the GR methodology for interior hotspot engineering demonstrates the potential for enabling the fabrication of SERS platforms with practical applications.

Formicary-like PtBi1.5Ni0.2Co0.2Cu0.2 high-entropy alloy aerogels as an efficient and stable electrocatalyst for methanol oxidation reaction

High-entropy alloy aerogels (HEAAs) have become promising electrochemical catalysts because of the advantageous combination of high-entropy alloys and aerogel structure. However, how to fabricate 3D porous high-entropy alloys accurately is still a great challenge due to their inherent thermodynamic instability and differences in reduction potentials of metal ions. Herein, PtBi1.5Ni0.2Co0.2Cu0.2 HEAAs have been synthesized by combining co-reduction method and freeze-drying technology. The resulting PtBi1.5Ni0.2Co0.2Cu0.2 HEAAs have the structural and morphological benefits of both high-entropy alloys and aerogels. Both XPS and DFT results confirm that the d-band center of PtBi1.5Ni0.2Co0.2Cu0.2 HEAAs shifts to lower binding energy compared to Pt/C, indicating the effective regulation of electronic structure on the surface of PtBi1.5Ni0.2Co0.2Cu0.2 HEAAs. As a demonstration in the methanol oxidation reaction (MOR), a mass activity of 4.19 A mgPt−1 and long-term stability (>0.33 A mgPt−1 after 10 cycles of 3600 s stability test) can be obtained on the PtBi1.5Ni0.2Co0.2Cu0.2 HEAAs, outperforming binary Pt-based alloys and commercial Pt/C. The CO adsorption strength of PtBi1.5Ni0.2Co0.2Cu0.2 HEAAs is more weaker than that of PtBi1.5 alloys and Pt/C, which proves the enhanced CO tolerance. The results pave the way for fabricating the hybrids of high-entropy alloys and aerogels with superior activity and stability.

Copper-Catalyzed Enantioselective Difluoromethylation-Alkynylation of Olefins by Solving the Dilemma between Acidities and Reduction Potentials of Difluoromethylating Agents.

Molecules containing a difluoromethyl group or a propargylic stereocenter are widely used in pharmaceuticals and agrochemicals, and 1,2-functionalization of olefins is an important method for introducing the two groups into molecules simultaneously. The construction of the propargylic stereocenter with terminal alkynes usually requires bases. However, difluoromethylating agents with high reduction potentials often decompose in the presence of bases because of their acidities, and those with low reduction potentials are stable but difficult to undergo the desired single electron transfer (SET) reduction. Using the linear relationship between reduction potential differences (ΔE) and Hammett substituent constants (σ) of difluoromethyl aryl sulfones, we solved the dilemma between acidities and reduction potentials of difluoromethylating agents. Herein, we report the first enantioselective difluoromethylation-alkynylation of olefins with difluoromethyl 4-chlorophenyl sulfone with high enantioselectivity (>90 % ee). We also extended this asymmetric fluoroalkylation-alkynylation reaction with other fluoroalkyl sulfones, which enabled efficient installation of trifluoromethyl, difluoroalkyl, difluorobenzyl, (benzenesulfonyl)-difluoromethyl and monofluoromethyl groups into products.

Copper‐Catalyzed Enantioselective Difluoromethylation‐Alkynylation of Olefins by Solving the Dilemma between Acidities and Reduction Potentials of Difluoromethylating Agents

AbstractMolecules containing a difluoromethyl group or a propargylic stereocenter are widely used in pharmaceuticals and agrochemicals, and 1,2‐functionalization of olefins is an important method for introducing the two groups into molecules simultaneously. The construction of the propargylic stereocenter with terminal alkynes usually requires bases. However, difluoromethylating agents with high reduction potentials often decompose in the presence of bases because of their acidities, and those with low reduction potentials are stable but difficult to undergo the desired single electron transfer (SET) reduction. Using the linear relationship between reduction potential differences (ΔE) and Hammett substituent constants (σ) of difluoromethyl aryl sulfones, we solved the dilemma between acidities and reduction potentials of difluoromethylating agents. Herein, we report the first enantioselective difluoromethylation‐alkynylation of olefins with difluoromethyl 4‐chlorophenyl sulfone with high enantioselectivity (&gt;90 % ee). We also extended this asymmetric fluoroalkylation‐alkynylation reaction with other fluoroalkyl sulfones, which enabled efficient installation of trifluoromethyl, difluoroalkyl, difluorobenzyl, (benzenesulfonyl)‐difluoromethyl and monofluoromethyl groups into products.

Compositional modulation through galvanic displacement in electrochemically deposited FeCoNiCuZn high entropy alloy thin films

After completing the aqueous electrodeposition of FeCoNiCuZn nanocrystalline high entropy (HEA) alloy system consisting of elements with significant differences in melting points and reduction potentials, unwanted galvanic displacement reactions (GDR) were observed on the alloy system when the film was held back in the electrolyte. This phenomenon, observed in alloys electroplated from aqueous baths containing a noble metal (currently Cu), leads to preferential deposition of the noble elements and changes the composition progressively at open circuit potential. A change in composition occurs in the electrodeposited alloy where Cu (from ∼13 to 58 at. %) was deposited on the alloy due to its nobler reduction potential causing displacement of Zn > Fe ∼ Co > Ni (order of displacement) from the deposited alloy with the Cu2+ ions present in the electrolyte. This work is the first observational report of galvanic displacement in HEAs composed of five elements. We categorically state that this GDR is crucial when designing/synthesizing HEAs alloys through electrodeposition.

Retrospective carbon reduction potential of residential buildings in China based on equity and efficiency coupling

Carbon dioxide (CO2) mitigation in the residential building sector has become critical for China in achieving its carbon peak and neutrality goals. This study is the first to retrospect the historical carbon reduction potential in China's 30 provinces by establishing an equity and efficiency coupling model and comparing the differences in carbon reduction potential under three scenarios: equity priority, efficiency priority scenario, and balance equity with efficiency. The core findings of this study reveal that: (1) China's total CO2 emissions in residential buildings increased from 975.67 Mt to 1328.47 Mt during 2010–2020, where the provinces with the highest CO2 emissions are Shandong, Hebei, and Henan; energy intensity and energy carbon emission coefficient are the most critical driving factors affecting the CO2 emission, followed by floor area per capita and population size. (2) The carbon reduction potential index of residential buildings in eastern provinces is generally higher than that in western provinces; the growth rate of carbon reduction potential is the fastest under the equity priority scenario, and Beijing, Shanghai, and Inner Mongolia have the highest carbon reduction potential. (3) The provinces gradually enter a strong coupling status associated with the climate zones of residential buildings, while the coupling status of the urban area is higher than that of the rural area. Overall, this study adopts a new coupling perspective of equity and efficiency, where the proposed assessment model serves as a reference for measuring the retrospective CO2 mitigation effect in residential buildings in other countries.

How energy transition promotes pollution abatement in China’s industrial sector

Without a market for pollution permits, such byproducts as carbon dioxide bear no market price, resulting in a higher environmental degradation than the socially optimal level. The contribution of this paper lies in that we model production process by resorting to a relatively novel by-production approach resembles a multi-stage process and ensure that the economic and environmental sub-technologies are properly linked. The by-production Data Envelopment Analysis model is adjusted so that positive shadow prices are obtained. Then, we derive the shadow prices of carbon dioxide emission, which can be interpreted as its marginal abatement costs, for province-level industrial sector data in China for the period 1997–2019. We demonstrate that the shadow price of carbon has increased between 1997 and 2019, suggesting the policymakers’ efforts to curb carbon dioxide emission levels in manufacturing have borne fruit. We observe a significant variation in shadow prices across the different provinces and attempt to explain it using exogenous factors such as carbon productivity, non-fossil energy consumption, and urbanization rate. The findings reveal that improving energy efficiency and carbon productivity, fully taking into account the emission reduction potential and cost differences of areas, and transitioning to non-fossil energy will be helpful for China to reduce the carbon emissions of the manufacturing industry in the future.

General and scalable strategy for synthesis of Pt-rare earth alloys as highly durable oxygen reduction electrocatalysts

Platinum-rare earth (Pt-RE) alloys are effective oxygen reduction reaction (ORR) catalysts, which are promising to show robust durability in proton-exchange membrane fuel cells (PEMFCs). Whereas, the large difference in reduction potentials between the two kinds of metals and the very oxophilicity of RE elements bring big challenges in the controllable synthesis of Pt-RE alloys. Herein we propose a general and scalable strategy to synthesize Pt-RE catalysts with tunable compositions and microstructures. The as-obtained catalysts possess a lamellar structure with hierarchical pore sizes ranging from 4 to 8 nm and a typical face-centered cubic (FCC) crystalline structure, and the Pt and RE are homogeneously distributed in the alloys. The electronic structures of Pt are well modulated by incorporating RE atoms, resulting in the adjusted d band center for these Pt-RE alloys compare with Pt, which facilitates OH* adsorption behavior and accelerate the ORR kinetics. Furthermore, the energy barrier for Pt demetallation is enhanced by incorporating of RE into the Pt lattice, which significantly enhances ORR durability. Notably, the optimal Pt3Y catalyst exhibits a greatly improved catalytic activity, including a large half-wave potential (0.89 V, at an ultralow Pt loading of 7.8 μg cm−2), high mass activity (0.53 A mg−1 at 0.9 ViR-free) and robust stability (0.01 V decay after 60,000 cycles) exceeding the commercial Pt/C (0.06 V decay after 30,000 cycles). This study provides a new facile strategy for the controllable preparation of Pt-RE alloys, which might pave the way for the large-scale applications of PEMFCs.

Mechanistic Insight into Electron Transfer from Fe(II)-Bearing Clay Minerals to Fe (Hydr)oxides.

Electron transfer (ET) is the essence of most biogeochemical processes related to element cycling and contaminant attenuation, whereas ET between different minerals and the controlling mechanism remain elusive. Here, we used surface-associated Fe(II) as a proxy to explore ET between reduced nontronite NAu-2 (rNAu-2) and Fe (hydr)oxides in their coexisting systems. Results showed that ET could occur from rNAu-2 to ferrihydrite but not to goethite, and the ET amount was determined by the number of reactive sites and the reduction potential difference between rNAu-2 and ferrihydrite. ET proceeded mainly through the mineral-mineral interface, with a negligible contribution of dissolved Fe2+/Fe3+. Control experiments by adding K+ and increasing salinity together with characterizations by X-ray diffraction, scanning electron microscopy/energy-dispersive spectrometry, and atomic force microscopy suggested that ferrihydrite nanoparticles inserted the interlayer space in rNAu-2 where structural Fe(II) in rNAu-2 transferred electrons mainly through the basal plane to ferrihydrite. This study implicates the occurrence of ET between different redox-active minerals through the mineral-mineral interface. As minerals at different reduction potentials often coexist in soils/sediments, the mineral-mineral ET may play an important role in subsurface biogeochemical processes.

Galvanic Replacement Synthesis of Metal Nanostructures: Bridging the Gap between Chemical and Electrochemical Approaches

ConspectusGalvanic replacement synthesis involves oxidation and dissolution of atoms from a substrate while the salt precursor to another material with a higher reduction potential is reduced and deposited on the substrate. The driving force or spontaneity of such a synthesis comes from the difference in reduction potential between the redox pairs involved. Both bulk and micro/nanostructured materials have been explored as substrates for galvanic replacement synthesis. The use of micro/nanostructured materials can significantly increase the surface area, offering immediate advantages over the conventional electrosynthesis. The micro/nanostructured materials can also be intimately mixed with the salt precursor in a solution phase, resembling the setting of a typical chemical synthesis. The reduced material tends to be directly deposited on the surface of the substrate, just like the situation in an electrosynthesis. Different from an electrosynthesis where the two electrodes are spatially separated by an electrolyte solution, the cathodes and anodes are situated on the same surface, albeit at different sites, even for a micro/nanostructured substrate. Since the oxidation and dissolution reactions occur at sites different from those for reduction and deposition reactions, one can control the growth pattern of the newly deposited atoms on the same surface of a substrate to access nanostructured materials with diverse and controllable compositions, shapes, and morphologies in a single step. Galvanic replacement synthesis has been successfully applied to different types of substrates, including those made of crystalline and amorphous materials, as well as metallic and nonmetallic materials. Depending on the substrate involved, the deposited material can take different nucleation and growth patterns, resulting in diverse but well-controlled nanomaterials sought for a variety of studies and applications.In this Account, we recapitulate our efforts over the past two decades in fabricating metal nanostructures for a broad range of applications by leveraging the unique capability of galvanic replacement synthesis. We begin with a brief introduction to the fundamentals of galvanic replacement between metal nanocrystals and salt precursors, followed by a discussion of the roles played by surface capping agents in achieving site-selected carving and deposition for the fabrication of various bimetallic nanostructures. Two examples based on the Ag-Au and Pd-Pt systems are selected to illustrate the concept and mechanism. We then highlight our recent work on the galvanic replacement synthesis involving nonmetallic substrates, with a focus on the protocol, mechanistic understanding, and experimental control for the fabrication of Au- and Pt-based nanostructures with tunable morphologies. Finally, we showcase the unique properties and applications of nanostructured materials derived from galvanic replacement reactions for biomedicine and catalysis. We also offer some perspectives on the challenges and opportunities in this emerging field of research.

Charge redistribution in FeOOH nanoarray by ecological oxygen-reduction deposition for boosting electrocatalytic water oxidation

The exploration for economic and ecological strategies to fulfill macro-synthesis of highly efficient nano-electrocatalysts has always been a key concern for electrocatalytic energy conversion field. Herein, a room-temperature oxygen-reduction deposition method was proposed to achieve the scaled-up preparation of Ni incorporated polycrystalline FeOOH (Ni-FeOOH) nanosheets on Fe metal. Due to the reduction potential difference between Fe metal and O2 in the atmosphere, the O2 reduction would thermodynamically occur in the designed Ni2+ liquid layer covered on Fe metal. Therefore, Ni-FeOOH nanosheets would be in-situ generated on the surface within a short cycle of 20 min. Furthermore, the Ni heteroatom induced the charge redistribution in FeOOH, where the average valence of both Fe and Ni cations was shifted to high states. As a result, the decreased Fermi level and increased electron acceptor significantly reduced the energy barrier of rate-determining step (by ∼1.4 eV). Finally, polycrystalline Ni-FeOOH shows a low overpotential of 239 mV at 10 mA/cm2, a low Tafel slope of 33 mV dec-1, and a dramatically increased TOF value (32.6 times higher than pristine sample), which even surpass some mainstream electrocatalysts consisting of noble-metal composition. This work provides an in-depth insight on Ni-Fe interaction mechanism, as well as a highly economic and ecological strategy to design and synthesize scaled-up FeOOH based electrocatalysts for water oxidation.

A comparative analysis of carbon reduction potential for directly driven permanent magnet and doubly fed asynchronous wind turbines

AbstractWind power generation does not emit greenhouse gases or pollutants, but there are some carbon emissions from the manufacturing, transportation, operation, and waste disposal of wind turbines. Directly driven permanent magnet and doubly fed asynchronous wind turbines currently have the largest market share in China, but few Chinese studies have compared their differences in carbon reduction potential. This paper uses life cycle assessment (LCA) to quantitatively analyze the full life cycle carbon emissions of the two wind turbines to determine which type of wind turbine has greater carbon reduction potential, obtaining the following results. (1) The full life cycle greenhouse gas emissions of 2.5 MW directly driven permanent magnet and doubly fed asynchronous wind turbines are 8.48 and 10.43 g CO2/kWh, respectively. The direct‐driven permanent magnet wind turbine is superior in terms of carbon reduction. (2) The stage with the greatest impact and the greatest difference between the two wind turbines in the full life cycle is the production stage, during which the carbon emissions of the directly driven permanent magnet and doubly fed asynchronous wind turbines are 1.045 × 106 and 1.210 × 106 kg, respectively. (3) According to sensitivity analysis, proper waste disposal and transportation can reduce carbon emissions from wind turbines. These research findings can be used to help achieve carbon peaking and neutrality goals, as well as the technological development of wind power enterprises.

Selective Extraction of Silver and Palladium in Leachate Based on EDTA Complexation: Electrodeposition, Nucleation Mechanism, and Kinetic Analysis

The development of green recycling technology for precious metals such as Ag and Pd from secondary resources can prevent environmental pollution caused by improper disposal, and it can alleviate resource shortage and promote sustainable development. Ag and Pd often coexist in some solid waste. This study proposed the extraction of Ag and Pd stepwise from leachate through the green technology of potential-controlled electrodeposition, and the reduction potential difference of Ag and Pd in solution was increased based on EDTA (ethylenediaminetetraacetic acid) complexation. The electrochemical behavior of Ag+ and Pd2+ in solution was investigated. It was determined that the electrodeposition separation of Ag+ and Pd2+ can be achieved with a pH of 9 and an EDTA molar ratio of 1:1.5 in the solution. With sequential electrodeposition at 0 V and −0.7 V, 99.3% of Ag and 96.15% of Pd were recovered, respectively, and their purity was achieved 100%. Pd electrodeposition conformed to three-dimensional instantaneous nucleation and growth mechanism analyzed with the Scharifker–Hills model. Compared with the EDTA-free environment, the diffusion coefficient of ions reduced, and the activation energy of Ag and Pd reduction reaction increased in the EDTA environment. This study provides an environmentally friendly and efficient method for precious metal recovery from secondary resources.

Spatial-temporal characteristics and decoupling effects of China's transportation CO2 emissions.

Both the realization of the "double carbon" goal and the low-carbon economy development requires a focus on transportation CO2 emissions. Calculating Chinese transportation CO2 emissions and exploring its principles are essential for achieving high-quality development of the transportation industry. Firstly, we use a "top-down" method to assess carbon emissions from transportation operations from 2003 to 2019. Secondly, the study decomposes the influencing factors of transportation CO2 emissions in China using the log-average weight decomposition method. Thirdly, the Tapio decoupling model is applied to study the decoupling effect of transportation CO2 emissions in each province of China. The findings suggest that China's transport carbon emissions are growing at an annual rate of roughly 16%. All GDP per capita, transportation energy intensity, and population size increase the growth of transportation CO2 emissions. Contrastly, energy use per unit of turnover and transportation intensity decrease the growth of transportation CO2 emissions. There is much variation in China's carbon emission decoupling index from year to year. Policy recommendations are proposed in response to the study of the above findings and the differences in carbon reduction potential among provinces.