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Despite modern chemistry's success in providing affordable fertilizers for feeding the population and supporting the ammonia industry, ineffective nitrogen management has led to pollution of water resources and air, contributing to climate change. Here, we report a multifunctional copper single-atom electrocatalyst-based aerogel (Cu SAA) that integrates the multiscale structure of coordinated single-atomic sites and 3D channel frameworks. The Cu SAA demonstrates an impressive faradaic efficiency of 87% for NH3 synthesis, as well as remarkable sensing performance with detection limits of 0.15 ppm for NO3- and 1.19 ppm for NH4+. These multifunctional features enable precise control and conversion of nitrate to ammonia in the catalytic process, facilitating accurate regulation of the ammonium and nitrate ratios in fertilizers. We thus designed the Cu SAA into a smart and sustainable fertilizing system (SSFS), a prototype device for on-site automatic recycling of nutrients with precisely controlled nitrate/ammonium concentrations. The SSFS represents a forward step toward sustainable nutrient/waste recycling, thus permitting efficient nitrogen utilization of crops and mitigating pollutant emissions. This contribution exemplifies how electrocatalysis and nanotechnology can be potentially leveraged to enable sustainable agriculture.
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The electrochemical nitrate reduction reaction (NO3RR) holds promise for converting nitrogenous pollutants to valuable ammonia products. However, conventional electrocatalysis faces challenges in effectively driving the complex eight-electron and nine-proton transfer process of the NO3RR while also competing with the hydrogen evolution reaction. In this study, we present the thermally enhanced electrocatalysis of nitrate-to-ammonia conversion over nickel-modified copper oxide single-atom alloy oxide nanowires. The catalyst demonstrates improved ammonia production performance with a Faradaic efficiency of approximately 80% and a yield rate of 9.7 mg h-1 cm-2 at +0.1 V versus a reversible hydrogen electrode at elevated cell temperatures. In addition, this thermally enhanced electrocatalysis system displays impressive stability, interference resistance, and favorable energy consumption and greenhouse gas emissions for the simulated industrial wastewater treatment. Complementary in situ analyses confirm that the significantly superior relay of active hydrogen species formed at Ni sites facilitates the thermal-field-coupled electrocatalysis of Cu surface-adsorbed *NOx hydrogenation. Theoretical calculations further support the thermodynamic and kinetic feasibility of the relay catalysis mechanism for the NO3RR over the Ni1Cu model catalyst. This study introduces a conceptual thermal-electrochemistry approach for the synergistic regulation of complex catalytic processes, highlighting the potential of multifield-coupled catalysis to advance sustainable-energy-powered chemical synthesis technologies.
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Single-atom catalysts (SACs), specifically iron single atoms dispersed on nitrogen-doped carbon (Fe-NC), have shown promising potential in the electrocatalytic reduction of nitrate to ammonia (NitRR), but there is a lack of understanding of their intrinsic activity. The conventional measurements often overlook the intrinsic performance of SACs, leading to significant underestimation. This study presents an in situ electrochemical probing protocol, using two poisoning molecules (SCN- and NO2-), to characterize the reactivity of Fe sites in Fe-NC SACs for NitRR. The technique aids in quantifying the yield rate of ammonia on Fe sites and the active site number. The findings reveal the intrinsic turnover frequency (TOF) based on the number and ammonia yield rate of Fe sites, challenging the current understanding of SACs' inherent performances. This unique approach holds considerable potential for determining the intrinsic activity of other SACs in complex reactions, opening new avenues for the exploration of electrocatalytic processes.
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Cell-surface death receptors such as DR4 and DR5 trigger apoptosis through a death-inducing signaling complex (DISC) that recruits the apical protease caspase-8. Apoptosis commitment requires efficient activation and autocatalytic release of caspase-8 into the cytoplasm to engage executioner caspases. While DISC recruitment initiates caspase-8 stimulation, full activation of the protease depends on further molecular aggregation events that are not fully understood. Here, we show that death receptor ligation induces polyubiquitination of caspase-8, through a previously unknown interaction of the DISC with a cullin3 (CUL3)-based E3 ligase. CUL3-mediated caspase-8 polyubiquitination required the RING box protein RBX1, whereas the deubiquitinase A20 reversed this modification. The ubiquitin-binding protein p62/sequestosome-1 promoted aggregation of CUL3-modified caspase-8 within p62-dependent foci, leading to full activation and processing of the enzyme and driving commitment to cell death. These results identify a mechanism that positively controls apoptosis signaling by polyubiquitination and aggregation of a key initiator caspase.
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Proteínas Adaptadoras Transductoras de Señales/metabolismo , Caspasa 8/metabolismo , Proteínas Cullin/metabolismo , Apoptosis , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/metabolismo , Técnicas de Silenciamiento del Gen , Humanos , Transporte de Proteínas , Proteína Sequestosoma-1 , Ubiquitina/metabolismo , UbiquitinaciónRESUMEN
Hydrogen energy with its advantages of high calorific value, renewable nature, and zero carbon emissions is considered an ideal candidate for clean energy in the future. The electrochemical decomposition of water, powered by renewable and clean energy sources, presents a sustainable and environmentally friendly approach to hydrogen production. However, the traditional electrochemical overall water-splitting reaction (OWSR) is limited by the anodic oxygen evolution reaction (OER) with sluggish kinetics. Although important advances have been made in efficient OER catalysts, the theoretical thermodynamic difficulty predetermines the inevitable large potential (1.23 V vs. RHE for the OER) and high energy consumption for the conventional water electrolysis to obtain H2. Besides, the generation of reactive oxygen species at high oxidation potentials can lead to equipment degradation and increase maintenance costs. Therefore, to address these challenges, thermodynamically favorable anodic oxidation reactions with lower oxidation potentials than the OER are used to couple with the cathodic hydrogen evolution reaction (HER) to construct new coupling hydrogen production systems. Meanwhile, a series of robust catalysts applied in these new coupled systems are exploited to improve the energy conversion efficiency of hydrogen production. Besides, the electrochemical neutralization energy (ENE) of the asymmetric electrolytes with a pH gradient can further promote the decrease in application voltage and energy consumption for hydrogen production. In this review, we aim to provide an overview of the advancements in electrochemical hydrogen production strategies with low energy consumption, including (1) the traditional electrochemical overall water splitting reaction (OWSR, HER-OER); (2) the small molecule sacrificial agent oxidation reaction (SAOR) and (3) the electrochemical oxidation synthesis reaction (EOSR) coupling with the HER (HER-SAOR, HER-EOSR), respectively; (4) regulating the pH gradient of the cathodic and anodic electrolytes. The operating principle, advantages, and the latest progress of these hydrogen production systems are analyzed in detail. In particular, the recent progress in the catalytic materials applied to these coupled systems and the corresponding catalytic mechanism are further discussed. Furthermore, we also provide a perspective on the potential challenges and future directions to foster advancements in electrocatalytic green sustainable hydrogen production.
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Electroreduction of nitrate to ammonia offers a promising pathway for nutrient recycling and recovery from wastewater with energy and environmental sustainability. There have been considerable efforts on the regulation of reaction pathways to facilitate nitrate-to-ammonia conversion over the competing hydrogen evolution reaction but only with limited success. Here, we report a Cu single-atom gel (Cu SAG) electrocatalyst that produces NH3 from both nitrate and nitrite under neutral conditions. Given the unique mechanism of NO2- activation on Cu SAGs with spatial confinement and strengthened kinetics, a pulse electrolysis strategy is presented to cascade the accumulation and conversion of NO2- intermediates during NO3- reduction with the prohibited competition from the hydrogen evolution reaction, thus substantially enhancing the Faradaic efficiency and the yield rate for ammonia production compared with constant potential electrolysis. This work underlines the cooperative approach of the pulse electrolysis and SAGs with three-dimensional (3D) framework structures for highly efficient nitrate-to-ammonia conversion enabled by tandem catalysis of unfavorable intermediates.
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Harvesting recyclable ammonia (NH3) from the electrocatalytic reduction of nitrate (NO3RR) offers a sustainable strategy to close the ecological nitrogen cycle from nitration contamination in an energy-efficient and environmentally friendly manner. The emerging intermetallic single-atom alloys (ISAAs) are recognized to achieve the highest site density of single atoms by isolating contiguous metal atoms into single sites stabilized by another metal within the intermetallic structure, which holds promise to couple the catalytic benefits from intermetallic nanocrystals and single-atom catalysts for promoting NO3RR. Herein, ISAA In-Pd bimetallene, in which the Pd single atoms are isolated by surrounding In atoms, is reported to boost neutral NO3RR with a NH3 Faradaic efficiency (FE) of 87.2%, a yield rate of 28.06 mg h-1 mgPd-1, and an exceptional electrocatalytic stability with increased activity/selectivity over 100 h and 20 cycles. The ISAA structure induces substantially diminished overlap of Pd d-orbitals and narrowed p-d hybridization of In-p and Pd-d states around the Fermi level, resulting in a stronger NO3- adsorption and a depressed energy barrier of the potential-determining step for NO3RR. Further integrating the NO3RR catalyst into a Zn-NO3- flow battery as the cathode delivers a power density of 12.64 mW cm-2 and a FE of 93.4% for NH3 production.
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The real-time measurement of the individual or local electrocatalytic reactivity of catalyst particles instead of ensemble behavior is considerably challenging but very critical to uncover fundamental insights into catalytic mechanisms. Recent remarkable efforts have been made to the development of high-spatiotemporal-resolution electrochemical techniques, which allow the imaging of the topography and reactivity of fast electron-transfer processes at the nanoscale. This Perspective summarizes emerging powerful electrochemical measurement techniques for studying various electrocatalytic reactions on different types of catalysts. Principles of scanning electrochemical microscopy, scanning electrochemical cell microscopy, single-entity measurement, and molecular probing technique have been discussed for the purpose of measuring important parameters in electrocatalysis. We further demonstrate recent advances in these techniques that reveal quantitative information about the thermodynamic and kinetic properties of catalysts for various electrocatalytic reactions associated with our perspectives. Future research on the next-generation electrochemical techniques is anticipated to be focused on the development of instrumentation, correlative multimodal techniques, and new applications, thus enabling new opportunities for elucidating structure-reactivity relationships and dynamic information at the single active-site level.
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Anthropogenic nitrate pollution has an adverse impact on the environment and human health. As part of a sustainable nitrate management strategy, electrochemical denitrification is studied as an innovative strategy for nutrients recycling and recovering. It is, however, challenging to selectively electro-reduce nitrate with low-concentration for ammonia. Herein, the photo-deposition of size-defined Ru nanoclusters (NCs, average size: ≈1.66 nm) on TiO2 nanotubes (NTs) is demonstrated, which show improved performance for nitrate-to-ammonia electroreduction with a maximum yield rate of ≈600 µg h-1 cm-2 and a faradic efficiency (FE) of > 90.0% across a broad range of potentials in comparison with electrodeposited Ru nanoparticles (NPs, average size: ≈23.78 nm) on TiO2 NTs. Experimental and theoretical evidence further suggests the small-size Ru NCs with the intrinsically enhanced selectivity and activity because of the strong metal/substrate interaction and unsaturated coordination state. The findings highlight the size effect on Ru-based catalyst supported on metal oxides, a versatile catalytic model, which allows the regulation of hydrogen adsorption to favor ammonia production over the competing hydrogen evolution reaction.
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Single-atom catalysts (SACs) have aroused tremendous interest over the past decade, particularly in the community of energy and environment-related electrocatalysis. A rapidly growing number of recent publications have recognized it as a promising candidate with maximum atomic utilization, distinct activity, and selectivity in comparison to bulk catalysts and nanocatalysts. However, the complexity of localized coordination environments and the dispersion of isolated sites lead to significant difficulties when it comes to gaining insight into the intrinsic behavior of electrocatalytic reactions. Furthermore, the low metal loadings of most SACs make conventional ensemble measurements less likely to be accurate on the subnanoscale. Thus, it remains challenging to probe the activity and properties of individual atomic sites by available commercial instruments and analytical methods. In spite of this, continuing efforts have lately focused on the development of advanced measurement methodologies, which are very useful to the fundamental understanding of SACs. There have recently been a number of in situ/operando techniques applied to SACs, such as electron microscopy, spectroscopy, and other analysis methods, which support relevant functions to identify the active sites and reaction intermediates and to investigate the dynamic behavior of localized structures of the catalytic sites.This Account aims to present recent electrochemical probing techniques which can be used to identify single-atomic catalytic sites within solid supports. First, we describe the basic principles of molecular probe methods for the study and analysis of electrocatalytic site behavior. In particular, the in situ probing technique enabled by surface interrogation scanning electrochemical microscopy (SI-SECM) can measure the active site density and kinetic rate with high resolution. An alternative electrochemical probing technique is further demonstrated on the basis of single-entity electrochemistry, which allows the unique electrochemical imaging of the size and catalytic rate of single atoms, molecules, and clusters. The merits and limitations of different electrochemical techniques are then discussed, along with perspectives for future prospects. Apart from this, we further showcase the powerful capability of emerging electrochemical probing techniques for determining significant effects and properties of SACs for various electrocatalytic reactions, including oxygen reduction and evolution, hydrogen evolution, and nitrate reduction. Overall, electrochemical techniques with atomic resolution have greatly increased opportunities for observing, measuring, and understanding the surface and interface chemistry during energy conversion. In the future, it is anticipated that the development of electrochemical probing techniques will be advanced with innovative perspectives on the behavior and features of SACs. We hope that this Account can contribute in several ways to promoting the fundamental knowledge and technical progress of emerging electrochemical measurements for studying SACs.
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Técnicas Electroquímicas , Hidrógeno , Catálisis , Técnicas Electroquímicas/métodos , Cinética , Metales/químicaRESUMEN
We report an electrodeposition protocol for preparing isolated cobalt oxide single molecules (Co1Ox) and clusters (Co n Oy) on a carbon fiber nanoelectrode. The as-prepared deposits are able to produce well-defined steady-state voltammograms for the oxygen evolution reaction (OER) in alkaline media, where the equivalent radius (rd) is estimated by the limiting current of hydroxide oxidation in accordance with the electrocatalytic amplification model. The size of isolated clusters obtained from the femtomolar Co2+ solution through an atom-by-atom technique can reach as small as 0.21 nm (rd) which is approximately the length of Co-O bond in cobalt oxide. Therefore, the deposit was close to that of a Co1Ox single molecule with only one cobalt ion, the minimum unit of the cobalt-based oxygen-evolving catalyst. Additionally, the size-dependent catalysis of the OER on Co n Oy deposits shows a faster relative rate on the smaller cluster in terms of the potential at a given current density, implying the single molecular catalyst shows a superior OER activity.
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OBJECTIVE: B7-H3 is a member of the B7 family of immune checkpoint molecule. Although B7-H3 has been shown to regulate T cell-mediated peripheral immune response, whether it also correlated with NK cell exhaustion in ovarian cancer remains unclear. The purpose of this study was to explore the mechanism of B7-H3 regulating NK-cell proliferation and function. MATERIAL AND METHODS: To investigate the relationship between B7-H3 expression and the NK-cell function in ovarian cancer, human ovarian tumor tissues and cell lines were first examined the protein and mRNA expression of B7-H3 by quantitative real-time PCR (qRT-PCR), Immunohistochemistry and Western-blot assays. Then we established B7-H3 knockout cell lines and measured the cytotoxicity of NK cells on these cells by LDH release assay and Flow Cytometry. In addition, we analyzed B7-H3 in the regulation of glycolysis and glycolysis-related proteins by Glycolysis Stress Test, Glucose Consumption Assay and Western-blot. Moreover, luciferase reporter assay was used to confirm the directly regulation of miR-29c to B7-H3. Finally, we carried out in vivo experiments. RESULTS: We observed that tumor-expressed B7-H3 inhibits NK-cell function in vitro and in vivo, and is associated with glycolysis of ovarian cancer cell. Therapeutically, B7-H3 blockade prolonged the survival of SKOV3 tumor-bearing mice. In addition, miR-29c improved the anti-tumor efficacy of NK-cell by directly targeting B7-H3 in vitro were observed, but not in vivo. CONCLUSION: Our results demonstrate that miR-29c downregulates B7-H3 to inhibit NK-cell exhaustion and associated with glycolysis, which suggest that NK cells may be a new target of anti-B7-H3 therapy in ovarian cancer patients.
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Antígenos B7/inmunología , Carcinoma Epitelial de Ovario/inmunología , Células Asesinas Naturales/inmunología , Neoplasias Ováricas/inmunología , Animales , Antígenos B7/biosíntesis , Antígenos B7/genética , Carcinoma Epitelial de Ovario/genética , Línea Celular Tumoral , Regulación hacia Abajo , Femenino , Xenoinjertos , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos NOD , Ratones SCID , MicroARNs/genética , MicroARNs/inmunología , Persona de Mediana Edad , Neoplasias Ováricas/genéticaRESUMEN
Surface interrogation scanning electrochemical microscopy (SI-SECM) of two electrodeposited manganese-based electrocatalysts, amorphous MnOx and perovskite CaMnO3 , was used to investigate the manganese oxidation state relating to the oxygen evolution reaction (OER) under neutral conditions. The results indicate the amounts of MnIII and MnIV species in MnOx and CaMnO3 depend on potential. A MnV species was identified in both structures during the OER. Time-delay titration of MnV further revealed that MnOx produced two types of active sites with different OER reaction rates: k'fast (MnOx )=1.21â s-1 and k'slow (MnOx )=0.24â s-1 . In contrast, CaMnO3 perovskites in which the MnV species formed at a less positive potential than that in MnOx , displayed only one kinetic behavior with a faster reaction rate of 1.72â s-1 .
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A surface-strained and geometry-optimized TiO2 nanoreactor enhances the performance of electrocatalytic nitrogen fixation. The nanotubular confinement allows spatial regulation of the mass transport of nitrogen during the NRR process and offers an enlarged surface area, thus boosting the ammonia production with high selectivity. Both experimental and theoretical evidence support strained Ti3+ sites, demonstrating a more favorable pathway for the N2 activation and selective NH3 production with a faster kinetic rate than the pristine TiO2 . The TiO2 -based nanoreactor with surface and bulk structure tailoring delivered an NH3 yield rate up to 5.50â µg h-1 cm-2 (16.67â µg h-1 mgcat -1 ) and high faradaic efficiency of 26 % under ambient aqueous conditions. Our findings highlight the concept of lattice strain and geometry modified nanoreactors, which will have broad implications in the renewable energy catalysis and electrosynthesis of valuable products.
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Preceding antibody constant regions are switch (S) regions varying in length and repeat density that are targets of activation-induced cytidine deaminase. We asked how participating S regions influence each other to orchestrate rearrangements at the IgH locus by engineering mice in which the weakest S region, Sε, is replaced with prominent recombination hotspot Sµ. These mice produce copious polyclonal IgE upon challenge, providing a platform to study IgE biology and therapeutic interventions. The insertion enhances ε germ-line transcript levels, shows a preference for direct vs. sequential switching, and reduces intraswitch recombination events at native Sµ. These results suggest that the sufficiency of Sµ to mediate IgH rearrangements may be influenced by context-dependent cues.
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Cambio de Clase de Inmunoglobulina/genética , Inmunoglobulina E/metabolismo , Recombinación Genética , Alelos , Animales , Linfocitos B/metabolismo , Técnicas de Sustitución del Gen , Marcación de Gen , Sitios Genéticos/genética , Células Germinativas/metabolismo , Hibridomas , Cadenas epsilon de Inmunoglobulina/genética , Cadenas mu de Inmunoglobulina/genética , Activación de Linfocitos/genética , Ratones , Modelos Animales , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
Cells expressing oncogenic c-Myc are sensitized to TNF superfamily proteins. c-Myc also is an important factor in determining whether a cell is sensitive to TRAIL-induced apoptosis, and it is well established that the mitochondrial pathway is essential for apoptosis induced by c-Myc. We investigated whether c-Myc action on the mitochondria is required for TRAIL sensitivity and found that Myc sensitized cells with defective intrinsic signaling to TRAIL. TRAIL induced expression of antiapoptotic Mcl-1 and cIAP2 through activation of NF-kappaB. Both Myc and the multikinase inhibitor sorafenib block NF-kappaB. Combining sorafenib with TRAIL in vivo showed dramatic efficacy in TRAIL-resistant tumor xenografts. We propose the combination of TRAIL with sorafenib holds promise for further development.
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Antineoplásicos/farmacología , Apoptosis/fisiología , Bencenosulfonatos/farmacología , Proteínas Inhibidoras de la Apoptosis/fisiología , Proteínas de Neoplasias/fisiología , Proteínas Proto-Oncogénicas c-bcl-2/fisiología , Proteínas Proto-Oncogénicas c-myc/fisiología , Piridinas/farmacología , Ligando Inductor de Apoptosis Relacionado con TNF/fisiología , Animales , Apoptosis/efectos de los fármacos , Proteína 3 que Contiene Repeticiones IAP de Baculovirus , Línea Celular Tumoral , Femenino , Humanos , Proteínas Inhibidoras de la Apoptosis/genética , Ratones , Ratones Desnudos , Proteína 1 de la Secuencia de Leucemia de Células Mieloides , Proteínas de Neoplasias/genética , Niacinamida/análogos & derivados , Compuestos de Fenilurea , Proteínas Proto-Oncogénicas c-bcl-2/genética , Sorafenib , Transcripción Genética/fisiología , Ubiquitina-Proteína LigasasRESUMEN
PURPOSE: The influence of mechanical stimulation on the formation of torus mandibularis (TM) is still poorly understood. We sought to understand the etiology of TMs by investigating the role of parafunctional activity and mandibular morphology on the formation of TMs. MATERIALS AND METHODS: We designed a case-control study for patients attending the dental clinic of the present study (University of São Paulo School of Dentistry, São Paulo, SP, Brazil). Patients presenting with TMs were defined as cases, and those without TMs were defined as controls. Finite element analysis (FEA) was used in 3-dimensional mandibular models to examine the stress distribution in the mandibles with and without TMs. In addition, the associations of mandibular arch shape, mandibular cortical index, and parafunctional activity with the presence of T were assessed using odds ratio analysis. RESULTS: A total of 10 patients with TMs and 37 without TMs were selected (22 men and 25 women, mean age 54.3 ± 8.4 years). FEA showed a stress concentration in the region in which TMs form during simulation of parafunctional activity. The radiographic assessment showed that those with TMs were more likely to have a square-shaped mandible with sharp angles (P = .001) and a normal mandibular cortex (P = .03). The subjects without TMs had a round-shaped mandible with obtuse angles and an eroded mandibular cortex. CONCLUSIONS: Parafunctional activity could be causing the formation of TMs by concentrating mechanical stress in the region in which TMs usually form. Thus, mandibular geometries that favor stress concentration, such as square-shaped mandibles, will be associated with a greater prevalence of TMs.
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Exostosis/fisiopatología , Mandíbula/anomalías , Mandíbula/patología , Paladar Duro/anomalías , Estrés Mecánico , Estudios de Casos y Controles , Exostosis/diagnóstico por imagen , Exostosis/patología , Femenino , Análisis de Elementos Finitos , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Mandíbula/fisiopatología , Paladar Duro/diagnóstico por imagen , Paladar Duro/patología , Paladar Duro/fisiopatología , Radiografía PanorámicaRESUMEN
The selective two-electron electrochemical oxygen reduction reaction (ORR) for hydrogen peroxide (H2O2) production is a promising and green alternative method to the current energy-intensive anthraquinone process used in industry. In this study, we develop a single-atom catalyst (CNT-D-O-Fe) by anchoring defect-stabilized and oxygen-coordinated iron atomic sites (Fe-O4) onto porous carbon nanotubes using a local etching strategy. Compared to O-doped CNTs with vacancy defects (CNT-D-O) and oxygen-coordinated Fe single-atom site modifying CNTs without a porous structure (CNT-O-Fe), CNT-D-O-Fe exhibits the highest H2O2 selectivity of 94.4% with a kinetic current density of 13.4 mA cm-2. Fe-O4 single-atom sites in the catalyst probably contribute to the intrinsic reactivity for the two-electron transfer process while vacancy defects greatly enhance the electrocatalytic stability. Theoretical calculations further support that the coordinated environment and defective moiety in CNT-D-O-Fe could efficiently optimize the adsorption strength of the *OOH intermediate over the Fe single atomic active sites. This contribution sheds light on the potential of defect-stabilized and oxygen-coordinated single-atom metal sites as a promising avenue for the rational design of highly efficient and selective catalysts towards various electrocatalytic reactions.
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We report a wire-shaped bifunctional oxygen photoelectrode by integrating Li-doped TiO2 nanotubes and Pt nanoclusters. Conductive nanoshells have been identified at the lithiated interface of Pt/TiO2, which facilitates the performance of oxygen catalysis. Thus, the assembled Zn-air micro-battery with solar-assisted charging greatly improves the voltage efficiency compared with the conventional state-of-the-art catalyst as the air electrode.
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As an emerging class of materials with distinctive physicochemical properties, metallenes are deemed as efficient catalysts for energy-related electrocatalytic reactions. Engineering the lattice strain, electronic structure, crystallinity, and even surface porosity of metallene provides a great opportunity to further enhance its catalytic performance. Herein, we rationally developed a reconstruction strategy of Pd metallenes at atomic scale to generate a series of nonmetallic atom-intercalated Pd metallenes (M-Pdene, M = H, N, C) with lattice expansion and S-doped Pd metallene (S-Pdene) with an amorphous structure. Catalytic performance evaluation demonstrated that N-Pdene exhibited the highest mass activities of 7.96 A mg-1, which was 10.6 and 8.5 time greater than those of commercial Pd/C and Pt/C, respectively, for methanol oxidation reaction (MOR). Density functional theory calculations suggested that the well-controlled lattice tensile strain as well as the strong p-d hybridization interaction between N and Pd resulted in enhanced OH adsorption and weakened CO adsorption for efficient MOR catalysis on N-Pdene. When tested as hydrogen evolution reaction (HER) catalysts, the amorphous S-Pdene delivered superior activity and durability relative to the crystalline counterparts because of the disordered Pd surface with a further elongated bond length and a downshifted d-band center. This work provides an effective strategy for atomic engineering of metallene nanomaterials with high performance as electrocatalysts.