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1.
Cancer Nurs ; 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38259073

RESUMO

BACKGROUND: Colorectal cancer is one of the most common malignancies worldwide. Oxaliplatin, which is used as adjuvant chemotherapy, affects quality of life by causing oxaliplatin-induced peripheral neuropathy in colorectal cancer patients. OBJECTIVES: This study examined the effects of an application (app)-based physical activity program for alleviating peripheral neuropathy symptoms in colorectal cancer patients undergoing chemotherapy. METHODS: This was a randomized controlled study that included 34 patients undergoing chemotherapy after being diagnosed with colorectal cancer. Outcomes were compared between patients who participated in a 6-week app-based physical activity program (experimental group; n = 17) and who received standard booklet education (control group; n = 17). Data were collected using questionnaires, and exercise time was recorded to evaluate intervention adherence. RESULTS: Significant differences were observed between the groups in peripheral neuropathy symptoms (F = 8.93, P = .002), interference with activities (Z = -2.55, P = .011), and quality of life (F = 7.65, P = .003). The experimental group showed significantly higher average exercise times at 1 to 4 weeks (Z = -2.10, P = .026), 5 to 6 weeks (Z = -4.02, P < .001), and 1 to 6 weeks (Z = -3.40, P = .001) than the control group. CONCLUSIONS: The app-based physical activity program had a positive effect on participants' exercise adherence and reduced peripheral neuropathy symptoms. Thus, we propose the adoption of a mobile health app that can be used at any time or place as an intervention for preventing or alleviating adverse effects during the treatment of cancer patients. IMPLICATIONS FOR PRACTICE: An app-based physical activity program using the mobile health app can be used as a nursing intervention to manage symptoms and increase the health behavior adherence in cancer patients.

2.
Adv Mater ; 36(13): e2313032, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38113897

RESUMO

The catalytic activity and product selectivity of the electrochemical CO2 reduction reaction (eCO2RR) depend strongly on the local microenvironment of mass diffusion at the nanostructured catalyst and electrolyte interface. Achieving a molecular-level understanding of the electrocatalytic reaction requires the development of tunable metal-ligand interfacial structures with atomic precision, which is highly challenging. Here, the synthesis and molecular structure of a 25-atom silver nanocluster interfaced with an organic shell comprising 18 thiolate ligands are presented. The locally induced hydrophobicity by bulky alkyl functionality near the surface of the Ag25 cluster dramatically enhances the eCO2RR activity (CO Faradaic efficiency, FECO: 90.3%) with higher CO partial current density (jCO) in an H-cell compared to Ag25 cluster (FECO: 66.6%) with confined hydrophilicity, which modulates surface interactions with water and CO2. Remarkably, the hydrophobic Ag25 cluster exhibits jCO as high as -240 mA cm-2 with FECO >90% at -3.4 V cell potential in a gas-fed membrane electrode assembly device. Furthermore, this cluster demonstrates stable eCO2RR over 120 h. Operando surface-enhanced infrared absorption spectroscopy and theoretical simulations reveal how the ligands alter the neighboring water structure and *CO intermediates, impacting the intrinsic eCO2RR activity, which provides atomistic mechanistic insights into the crucial role of confined hydrophobicity.

3.
J Am Chem Soc ; 145(50): 27407-27414, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38055351

RESUMO

Unraveling the atomistic synergistic effects of nanoalloys on the electrocatalytic CO2 reduction reaction (eCO2RR), especially in the presence of copper, is of paramount importance. However, this endeavor encounters significant challenges due to the lack of the crystallographically determined atomic-level structure of appropriate monometallic and bimetallic analogues. Herein, we report a one-pot synthesis and structure characterization of a AuCu nanoalloy cluster catalyst, [Au15Cu4(DPPM)6Cl4(C≡CR)1]2+ (denoted as Au15Cu4). Single-crystal X-ray diffraction analysis reveals that Au15Cu4 comprises two interpenetrating incomplete, centered icosahedra (Au9Cu2 and Au8Cu3) and is protected by six DPPM, four halide, and one alkynyl ligand. The Au15Cu4 cluster and its closest monometal structural analogue, [Au18(DPPM)6Br4]2+ (denoted as Au18), as model systems, enable the elucidation of the atomistic synergistic effects of Au and Cu on eCO2RR. The results reveal that Au15Cu4 is an excellent eCO2RR catalyst in a gas diffusion electrode-based membrane electrode assembly (MEA) cell, exhibiting a high CO Faradaic efficiency (FECO) of >90%, and this efficiency is substantially higher than that of the undoped Au18 (FECO: 60% at -3.75 V). Au15Cu4 exhibits an industrial-level CO partial current density of up to -413 mA/cm2 at -3.75 V with the gas CO2-fed MEA, which is 2-fold higher than that of Au18. The density functional theory (DFT) calculations demonstrate that the synergistic effects are induced by Cu doping, where the exposed pair of AuCu dual sites was suggested for launching the eCO2RR process. Besides, DFT simulations reveal that these special dual sites synergistically coordinate a moderate shift in the d-state, thus enhancing its overall catalytic performance.

4.
J Am Chem Soc ; 145(42): 23068-23075, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37807716

RESUMO

Cations in an electrolyte modulate microenvironments near the catalyst surface and affect product distribution from an electrochemical CO2 reduction reaction, and thus, their interaction with intermediate states has been tried to be probed. Herein, we directly observed the cation effect on *CO intermediates on the Cu(OH)2-derived catalyst in real time through operando surface-enhanced Raman spectroscopy at high overpotentials (-1.0 VRHE). Atop *CO peaks are composed of low-frequency binding *CO (*COLFB) and high-frequency binding *CO (*COHFB) because of their adsorption sites. These two *CO intermediates are found to have different sensitivities to the cation-induced field, and each *CO is proposed to be suitably stabilized for efficient C-C coupling. The proportions between *COHFB and *COLFB are dependent on the type of alkali cations, and the increases in the *COHFB ratio have a high correlation with selective C2H4 production under K+ and Cs+, indicating that *COHFB is the dominant and fast active species. In addition, as the hydrated cation size decreases, *COLFB is more sensitively red-shifted than *COHFB, which promotes C-C coupling and suppresses C1 products. Through time-resolved operando measurements, dynamic changes between the two *CO species are observed, showing the rapid initial adsorption of *COHFB and subsequently reaching a steady ratio between *COLFB and *COHFB.

5.
Nat Commun ; 14(1): 4704, 2023 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-37543676

RESUMO

Direct partial oxidation of methane to liquid oxygenates has been regarded as a potential route to valorize methane. However, CH4 activation usually requires a high temperature and pressure, which lowers the feasibility of the reaction. Here, we propose an electro-assisted approach for the partial oxidation of methane, using in-situ cathodically generated reactive oxygen species, at ambient temperature and pressure. Upon using acid-treated carbon as the electrocatalyst, the electro-assisted system enables the partial oxidation of methane in an acidic electrolyte to produce oxygenated liquid products. We also demonstrate a high production rate of oxygenates (18.9 µmol h-1) with selective HCOOH production. Mechanistic analysis reveals that reactive oxygen species such as ∙OH and ∙OOH radicals are produced and activate CH4 and CH3OH. In addition, unstable CH3OOH generated from methane partial oxidation can be additionally reduced to CH3OH on the cathode, and so-produced CH3OH is further oxidized to HCOOH, allowing selective methane partial oxidation.

6.
Opt Lett ; 48(2): 347-350, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36638454

RESUMO

A photoelectrochemical (PEC) cell produces hydrogen energy using solar energy and an electrochemical reaction. In the hydrogen production process with water decomposition, electrons move from the anode to the cathode, and by measuring the current value at this time, the PEC cell can generate hydrogen and function as an image sensor at the same time. Due to the characteristics of the PEC cell that can perform both functions simultaneously, it can be applied as a device that can detect and respond to the surrounding environment without the need for an observation system such as a camera. We present the imaging performance of PEC cells. The effectiveness of the experiment was confirmed by applying the PEC cells to integral imaging, one of the three-dimensional (3D) imaging techniques.


Assuntos
Técnicas Eletroquímicas , Energia Solar , Técnicas Eletroquímicas/métodos , Imageamento Tridimensional , Hidrogênio/química
7.
J Am Chem Soc ; 145(6): 3401-3407, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36541445

RESUMO

While atomically monodisperse nanostructured materials are highly desirable to unravel the size- and structure-catalysis relationships, their controlled synthesis and the atomic-level structure determination pose challenges. Particularly, copper-containing atomically precise alloy nanoclusters are potential catalyst candidates for the electrochemical CO2 reduction reaction (eCO2RR) due to high abundance and tunable catalytic activity of copper. Herein, we report the synthesis and total structure of an alkynyl-protected 21-atom AgCu alloy nanocluster [Ag15Cu6(C≡CR)18(DPPE)2]-, denoted as Ag15Cu6 (HC≡CR: 3,5-bis(trifluoromethyl)phenylacetylene; DPPE: 1,2-bis(diphenylphosphino)ethane). The single-crystal X-ray diffraction reveals that Ag15Cu6 consists of an Ag11Cu4 metal core exhibiting a body-centered cubic (bcc) structure, which is capped by 2 Cu atoms, 2 Ag2DPPE motifs, and 18 alkynyl ligands. Interestingly, the Ag15Cu6 cluster exhibits excellent catalytic activity for eCO2RR with a CO faradaic efficiency (FECO) of 91.3% at -0.81 V (vs the reversible hydrogen electrode, RHE), which is much higher than that (FECO: 48.5% at -0.89 V vs RHE) of Ag9Cu6 with bcc structure. Furthermore, Ag15Cu6 shows superior stability with no significant decay in the current density and FECO during a long-term operation of 145 h. Density functional theory calculations reveal that the de-ligated Ag15Cu6 cluster can expose more space at the pair of AgCu dual metals as the efficient active sites for CO formation.

8.
Environ Res ; 211: 113116, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35304112

RESUMO

Electrochemical conversion of CO2 to fuels and chemicals as a sustainable solution for waste transformation has garnered tremendous interest to combat the fervent issue of the prevailing high atmospheric CO2 concentration while contributing to the generation of sustainable energy. Monometallic palladium (Pd) has been shown promising in electrochemical CO2 reduction, producing formate or CO depending on applied potentials. Recently, bimetallic Pd-based materials strived to fine-tune the binding affinity of key intermediates is a prominent strategy for the desired product formation from CO2 reduction. Herein, the recent emerging trends on bimetallic Pd-based electrocatalysts are reviewed, including fundamentals of CO2 electroreduction and material engineering of bimetallic Pd-electrocatalysts categorized by primary products. Modern analytical techniques on these novel electrocatalysts are also thoroughly studied to get insights into reaction mechanisms. Lastly, we deliberate over the challenges and prospects for Pd-based catalysts for electrochemical CO2 conversion.

9.
Small Methods ; 6(5): e2200074, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35212468

RESUMO

Copper-based catalysts have attracted enormous attention due to their high selectivity for C2+ products during the electrochemical reduction of CO2 (CO2 RR). In particular, grain boundaries on the catalysts contribute to the generation of various Cu coordination environments, which have been found essential for C-C coupling. However, smooth-surfaced Cu2 O nanocrystals generally lack the ability for the surface reorganization to form multiple grain boundaries and desired Cu undercoordination sites. Flow chemistry armed with the unparalleled ability to mix reaction mixture can achieve a very high concentration of unstable reaction intermediates, which in turn are used up rapidly to lead to kinetics-driven nanocrystal growth. Herein, the synthesis of a unique hierarchical structure of Cu2 O with numerous steps (h-Cu2 O ONS) via flow chemistry-assisted modulation of nanocrystal growth kinetics is reported. The surface of h-Cu2 O ONS underwent rapid surface reconstruction under CO2 RR conditions to exhibit multiple heterointerfaces between Cu2 O and Cu phases, setting the preferable condition to facilitate C-C bond formation. Notably, the h-Cu2 O ONS obtained the increased C2 H4 Faradaic efficiency from 31.9% to 43.5% during electrocatalysis concurrent with the morphological reorganization, showing the role of the stepped surface. Also, the h-Cu2 O ONS demonstrated a 3.8-fold higher ethylene production rate as compared to the Cu2 O nanocube.

10.
Antioxidants (Basel) ; 10(8)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34439449

RESUMO

The purpose of this study is to identify amino acid derivatives with potent anti-eumelanogenic activity. First, we compared the effects of twenty different amidated amino acids on tyrosinase (TYR)-mediated dopachrome formation in vitro and melanin content in dark-pigmented human melanoma MNT-1 cells. The results showed that only L-cysteinamide inhibited TYR-mediated dopachrome formation in vitro and reduced the melanin content of cells. Next, the antimelanogenic effect of L-cysteinamide was compared to those of other thiol compounds (L-cysteine, N-acetyl L-cysteine, glutathione, L-cysteine ethyl ester, N-acetyl L-cysteinamide, and cysteamine) and positive controls with known antimelanogenic effects (kojic acid and ß-arbutin). The results showed the unique properties of L-cysteinamide, which effectively reduces melanin content without causing cytotoxicity. L-Cysteinamide did not affect the mRNA and protein levels of TYR, tyrosinase-related protein 1, and dopachrome tautomerase in MNT-1 cells. L-Cysteinamide exhibited similar properties in normal human epidermal melanocytes (HEMs). Experiments using mushroom TYR suggest that L-cysteinamide at certain concentrations can inhibit eumelanin synthesis through a dual mechanism by inhibiting TYR-catalyzed dopaquinone synthesis and by diverting the synthesized dopaquinone to the formation of DOPA-cysteinamide conjugates rather than dopachrome. Finally, L-cysteinamide was shown to increase pheomelanin content while decreasing eumelanin and total melanin contents in MNT-1 cells. This study suggests that L-cysteinamide has an optimal structure that can effectively and safely inhibit eumelanin synthesis in MNT-1 cells and HEMs, and will be useful in controlling skin hyperpigmentation.

11.
Nat Commun ; 12(1): 4271, 2021 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-34257287

RESUMO

The voltage reversal of water electrolyzers and fuel cells induces a large positive potential on the hydrogen electrodes, followed by severe system degradation. Applying a reversible multifunctional electrocatalyst to the hydrogen electrode is a practical solution. Ir exhibits excellent catalytic activity for hydrogen evolution reactions (HER), and hydrogen oxidation reactions (HOR), yet irreversibly converts to amorphous IrOx at potentials > 0.8 V/RHE, which is an excellent catalyst for oxygen evolution reactions (OER), yet a poor HER and HOR catalyst. Harnessing the multifunctional catalytic characteristics of Ir, here we design a unique Ir-based electrocatalyst with high crystallinity for OER, HER, and HOR. Under OER operation, the crystalline nanoparticle generates an atomically-thin IrOx layer, which reversibly transforms into a metallic Ir at more cathodic potentials, restoring high activity for HER and HOR. Our analysis reveals that a metallic Ir subsurface under thin IrOx layer can act as a catalytic substrate for the reduction of Ir ions, creating reversibility. Our work not only uncovers fundamental, uniquely reversible catalytic properties of nanoparticle catalysts, but also offers insights into nanocatalyst design.

12.
J Am Chem Soc ; 143(14): 5386-5395, 2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33725440

RESUMO

Pd is one of the most effective catalysts for the electrochemical reduction of CO2 to formate, a valuable liquid product, at low overpotential. However, the intrinsically high CO affinity of Pd makes the surface vulnerable to CO poisoning, resulting in rapid catalyst deactivation during CO2 electroreduction. Herein, we utilize the interaction between metals and metal-organic frameworks to synthesize atomically dispersed Au on tensile-strained Pd nanoparticles showing significantly improved formate production activity, selectivity, and stability with high CO tolerance. We found that the tensile strain stabilizes all reaction intermediates on the Pd surface, whereas the atomically dispersed Au selectively destabilizes CO* without affecting other adsorbates. As a result, the conventional COOH* versus CO* scaling relation is broken, and our catalyst exhibits 26- and 31-fold enhancement in partial current density and mass activity toward electrocatalytic formate production with over 99% faradaic efficiency, compared to Pd/C at -0.25 V versus RHE.

13.
Adv Sci (Weinh) ; 7(23): 2001946, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33304753

RESUMO

Methane is an important fossil fuel and widely available on the earth's crust. It is a greenhouse gas that has more severe warming effect than CO2. Unfortunately, the emission of methane into the atmosphere has long been ignored and considered as a trivial matter. Therefore, emphatic effort must be put into decreasing the concentration of methane in the atmosphere of the earth. At the same time, the conversion of less valuable methane into value-added chemicals is of significant importance in the chemical and pharmaceutical industries. Although, the transformation of methane to valuable chemicals and fuels is considered the "holy grail," the low intrinsic reactivity of its C-H bonds is still a major challenge. This review discusses the advancements in the electrocatalytic and photocatalytic oxidation of methane at low temperatures with products containing oxygen atom(s). Additionally, the future research direction is noted that may be adopted for methane oxidation via electrocatalysis and photocatalysis at low temperatures.

14.
Chem Commun (Camb) ; 56(84): 12687-12697, 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-32985636

RESUMO

Single-atom catalysts (SACs) possess the potential to achieve unique catalytic properties and remarkable catalytic mass activity by utilizing low-coordination and unsaturated active sites. However, smaller particles tend to aggregate into clusters or particles owing to their high surface energy. In addition, support materials that have strong interactions with isolated metal atoms, extremely large surface areas, and electrochemical stability are required. Therefore, sufficient information about these factors is needed to synthesize and utilize SACs. Herein, we review the recent investigations and advances in SACs for the oxygen evolution reaction (OER). We present not only the structural characterization of SACs, but also in situ/operando spectroscopic techniques and computational research for SACs to understand the mechanism and reveal the origin of their excellent OER activity. Furthermore, the OER catalytic activity and stability of SACs are summarized to evaluate the current level of SACs. Currently, research on single-atoms as OER catalysts is in the infant stage for synthesis, characterization and mechanism studies. We discuss some challenges for understanding the fundamentals of SACs and enhancing the catalytic performance of SACs for industrial applications.

15.
Chem Soc Rev ; 49(18): 6632-6665, 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-32780048

RESUMO

The electrochemical reduction of CO2 stores intermittent renewable energy in valuable raw materials, such as chemicals and transportation fuels, while minimizing carbon emissions and promoting carbon-neutral cycles. Recent technoeconomic reports suggested economically feasible target products of CO2 electroreduction and the relative influence of key performance parameters such as faradaic efficiency (FE), current density, and overpotential in the practical industrial-scale applications. Furthermore, fundamental factors, such as available reaction pathways, shared intermediates, competing hydrogen evolution reaction, scaling relations of the intermediate binding energies, and CO2 mass transport limitations, should be considered in relation to the electrochemical CO2 reduction performance. Intensive research efforts have been devoted to designing and developing advanced electrocatalysts and improving mechanistic understanding. More recently, the research focus was extended to the catalyst environment, because the interfacial region can delicately modulate the catalytic activity and provide effective solutions to challenges that were not fully addressed in the material development studies. Herein, we discuss the importance of catalyst-electrolyte interfaces in improving key operational parameters based on kinetic equations. Furthermore, we extensively review previous studies on controlling organic modulators, electrolyte ions, electrode structures, as well as the three-phase boundary at the catalyst-electrolyte interface. The interfacial region modulates the electrocatalytic properties via electronic modification, intermediate stabilization, proton delivery regulation, catalyst structure modification, reactant concentration control, and mass transport regulation. We discuss the current understanding of the catalyst-electrolyte interface and its effect on the CO2 electroreduction activity.

16.
Nanoscale ; 12(27): 14903-14910, 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32638785

RESUMO

Electrochemical oxidation processes can affect the electronic structure and activate the catalytic performance of precious-metal and transition-metal based catalysts for the oxygen evolution reaction (OER). Also there are emerging requirements to develop OER electrocatalysts under various pH conditions in order to couple with different reduction reactions. Herein, we studied the effect of pH on the electroactivation of IrNi alloy nanoparticles supported on carbon (IrNi/C) and evaluated the electrocatalytic activities of the activated IrNiOx/C for water oxidation under neutral conditions. In addition, their electronic structures and atomic arrangement were analyzed by in situ/operando X-ray absorption spectroscopy (XAS) and identical location transmission electron microscopy techniques, showing the reconstruction of the metal elements during electroactivation due to their different stabilities depending on the electrolyte pH. IrNiOx/C activated under neutral pH conditions showed a mildly oxidized thin IrOx shell. Meanwhile, IrNiOx/C activated in acidic and alkaline electrolytes showed Ni-leached IrOx and Ni-rich IrNiOx surfaces, respectively. Particularly, the surface of IrNiOx/C activated under alkaline conditions shows IrOx with a high d-band hole and NiOx with a high oxidation state leading to excellent OER catalytic activity in neutral media (η = 384 mV at 10 mA cm-2) whereas much lower OER activity was reported under alkaline or acid conditions. Our results, which showed that electrochemically activated catalysts under different pH conditions exhibit a unique electronic structure by modifying the initial alloy catalyst, can be applied for the design of catalysts suitable for various electrochemical reactions.

17.
Int J Mol Sci ; 21(13)2020 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32605171

RESUMO

The aim of this study was to identify novel antimelanogenic drugs from an epigenetic screening library containing various modulators targeting DNA methyltransferases, histone deacetylases, and other related enzymes/proteins. Of 141 drugs tested, K8 (4-((hydroxyamino)carbonyl)-N-(2-hydroxyethyl)-N-phenyl-benzeneacetamide; HPOB) was found to effectively inhibit the α-melanocyte-stimulating hormone (α-MSH)-induced melanin synthesis in B16-F10 murine melanoma cells without accompanying cytotoxicity. Additional experiments showed that K8 did not significantly reduce the mRNA and protein level of tyrosinase (TYR) or microphthalmia-associated transcription factor (MITF) in cells, but it potently inhibited the catalytic activity TYR in vitro (IC50, 1.1-1.5 µM) as compared to ß-arbutin (IC50, 500-700 µM) or kojic acid (IC50, 63 µM). K8 showed copper chelating activity similar to kojic acid. Therefore, these data suggest that K8 inhibits cellular melanin synthesis not by downregulation of TYR protein expression through an epigenetic mechanism, but by direct inhibition of TYR catalytic activity through copper chelation. Metal chelating activity of K8 is not surprising because it is known to inhibit histone deacetylase (HDAC) 6 through zinc chelation. This study identified K8 as a potent inhibitor of cellular melanin synthesis, which may be useful for the treatment of hyperpigmentation disorders.


Assuntos
Antineoplásicos/farmacologia , Benzenoacetamidas/química , Epigênese Genética , Melaninas/metabolismo , Melanoma Experimental/tratamento farmacológico , Monofenol Mono-Oxigenase/antagonistas & inibidores , Preparações Farmacêuticas/administração & dosagem , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Preparações Farmacêuticas/isolamento & purificação , Células Tumorais Cultivadas
18.
Adv Mater ; 32(17): e1908398, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32134526

RESUMO

Electrochemical reduction of carbon dioxide (CO2 RR) product distribution has been identified to be dependent on various surface factors, including the Cu facet, morphology, chemical states, doping, etc., which can alter the binding strength of key intermediates such as *CO and *OCCO during reduction. Therefore, in-depth knowledge of the Cu catalyst surface and identification of the active species under reaction conditions aid in designing efficient Cu-based electrocatalysts. This progress report categorizes various Cu-based electrocatalysts into four main groups, namely metallic Cu, Cu alloys, Cu compounds (Cu + non-metal), and supported Cu-based catalysts (Cu supported by carbon, metal oxides, or polymers). The detailed mechanisms for the selective CO2 RR are presented, followed by recent relevant developments on the synthetic procedures for preparing Cu and Cu-based nanoparticles. Herein, the potential link between the Cu surface and CO2 RR performance is highlighted, especially in terms of the chemical states, but other significant factors such as defective sites and roughened morphology of catalysts are equally considered during the discussion of current studies of CO2 RR with Cu-based electrocatalysts to fully understand the origin of the significant enhancement toward C2 formation. This report concludes by providing suggestions for future designs of highly selective and stable Cu-based electrocatalysts for CO2 RR.

19.
Nat Commun ; 10(1): 5193, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31729357

RESUMO

Electrochemical processes coupling carbon dioxide reduction reactions with organic oxidation reactions are promising techniques for producing clean chemicals and utilizing renewable energy. However, assessments of the economics of the coupling technology remain questionable due to diverse product combinations and significant process design variability. Here, we report a technoeconomic analysis of electrochemical carbon dioxide reduction reaction-organic oxidation reaction coproduction via conceptual process design and thereby propose potential economic combinations. We first develop a fully automated process synthesis framework to guide process simulations, which are then employed to predict the levelized costs of chemicals. We then identify the global sensitivity of current density, Faraday efficiency, and overpotential across 295 electrochemical coproduction processes to both understand and predict the levelized costs of chemicals at various technology levels. The analysis highlights the promise that coupling the carbon dioxide reduction reaction with the value-added organic oxidation reaction can secure significant economic feasibility.

20.
Nat Commun ; 10(1): 3919, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477719

RESUMO

Pd metal and Pd-based alloys are ideal catalysts that allow for the electrochemical conversion of CO2 to HCOO- at almost zero-overpotential with high selectivity, but catalyst degradation caused by concurrent CO poisoning limits their practical implementation. Here, we demonstrate that cyclic two-step electrolysis, by applying the reduction and oxidation potentials alternately, achieves 100% current density stability and 97.8% selectivity toward HCOO- production for at least 45 h. The key idea for achieving the reliability is based on the selective removal of CO by controlling the parameters during the oxidation step, which utilizes the different reversibility of HCOO- and CO production reactions. Furthermore, it is found that potentiostatic electrolysis causes CO adsorption and subsequent dehydridation, which in turn lowers HCOO- selectivity. Our work provides a system-level strategy for solving the poisoning issue that is inevitable in many electrocatalytic reactions.

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