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The utilization of seawater for hydrogen production via water splitting is increasingly recognized as a promising avenue for the future. The key dilemma for seawater electrolysis is the incompatibility of superior hydrogen- and oxygen-evolving activities at ampere-scale current densities for both cathodic and anodic catalysts, thus leading to large electric power consumption of overall seawater splitting. Here, in situ construction of Fe4N/Co3N/MoO2 heterostructure arrays anchoring on metallic nickel nitride surface with multilevel collaborative catalytic interfaces and abundant multifunctional metal sites is reported, which serves as a robust bifunctional catalyst for alkaline freshwater/seawater splitting at ampere-level current density. Operando Raman and X-ray photoelectron spectroscopic studies combined with density functional theory calculations corroborate that Mo and Co/Fe sites situated on the Fe4N/Co3N/MoO2 multilevel interfaces optimize the reaction pathway and coordination environment to enhance water adsorption/dissociation, hydrogen adsorption, and oxygen-containing intermediate adsorption, thus cooperatively expediting hydrogen/oxygen evolution reactions in base. Inspiringly, this electrocatalyst can substantially ameliorate overall freshwater/seawater splitting at 1000 mA cm-2 with low cell voltages of 1.65/1.69 V, along with superb long-term stability at 500-1500 mA cm-2 for over 200 h, outperforming nearly all the ever-reported non-noble electrocatalysts for freshwater/seawater electrolysis. This work offers a viable approach to design high-performance bifunctional catalysts for seawater splitting.
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OBJECTIVE: While there are various health literacy scales that exist, none of health literacy scale suitable for pregnant women with gestational diabetes mellitus (GDM). To address this gap, this study aimed to develop GDM health literacy scale and evaluate its psychometric properties. METHODS: Based on the Delphi expert consultation, we developed the initial GDM health literacy scale. Item analysis was taken using a sample (n = 299) recruited in China to form formal scale. Additional participants (n = 395) completed survey to assess the internal consistency reliability, test-retest reliability, content validity, construct validity and criterion correlation validity of scale. RESULTS: The scale performed well in terms of internal consistency reliability, content validity, construct validity and criterion correlation validity. Test-retest reliability indicated that the instrument was effective at measuring health literacy of GDM over time. CONCLUSION: The scale is a reliable and valid measure of six domains of health literacy for GDM. PRACTICE IMPLICATIONS: The scale can be used to effectively evaluate the level of health literacy of pregnant women with GDM. The information can provide targeted health support for pregnant women with GDM to improve their health literacy and self-management ability.
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Técnica Delphi , Diabetes Gestacional , Letramento em Saúde , Psicometria , Humanos , Diabetes Gestacional/diagnóstico , Feminino , Gravidez , Reprodutibilidade dos Testes , Adulto , Inquéritos e Questionários/normas , China , Conhecimentos, Atitudes e Prática em Saúde , Gestantes/psicologiaRESUMO
Cobalt-nitrogen-carbon (Co-N-C) catalysts with a CoN4 structure exhibit great potential for oxygen reduction reaction (ORR), but the imperfect adsorption energy toward oxygen species greatly limits their reduction efficiency and practical application potential. Here, F-coordinated Co-N-C catalysts with square-pyramidal CoN4-F1 configuration are successfully synthesized using F atoms to regulate the axial coordination of Co centers via hydrothermal and chemical vapor deposition methods. During the synthesis process, the geometry structure of the Co atom converts from six-coordinated Co-F6 to square-pyramidal CoN4-F1 in the coordinatively unsaturated state, which provides an open binding site for the O2. The introduction of axial F atoms into the CoN4 plane alters the local atomic environment around Co, significantly improving the ORR activity and Zn-air batteries performance. In situ spectroscopy proves that CoN4-F1 sites strongly combine with the OOH* intermediate and facilitate the splitting of O-O bond, making OOH* readily decompose into O* and OH* via a dissociative pathway. Theoretical calculations confirm that the axial F atom effectively reduces the electronic density of the Co centers and facilitates the desorption of the OH* intermediate, efficiently accelerating the overall ORR kinetics. This work advances a feasible synthesis mechanism of axial ligands and provides a route to construct efficient high-coordination catalysts.
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Hydrogen evolution reaction (HER) in neutral or alkaline electrolytes is appealing for sustainable hydrogen production driven by water splitting, but generally suffers from unsatisfied catalytic activities at high current densities owing to extra kinetic energy barriers required to generate protons through water dissociation. In response, here, a competitive Ni3N/Co3N/CoP electrocatalyst with multifunctional interfacial sites and multilevel interfaces, in which Ni3N/CoP performs as active sites to boost initial water dissociation and Co3N/CoP accelerates subsequent hydrogen adsorption process as confirmed by density functional theory calculations and in situ X-ray photoelectron spectroscopy analysis, is reported. This hybrid catalyst possesses extraordinary HER activity in base, featured by extremely low overpotentials of 115 and 142 mV to afford 500 and 1000 mA cm-2, respectively, outperforming most ever-reported metal phosphides-based catalysts. This catalyst presents an ultrahigh current density of 3545 mA cm-2 by a factor of 4.96 relative to noble Pt/C catalysts (715 mA cm-2) at 0.2 V. Assembled with Fe(PO3)2/Ni2P anode, industrial-level current densities of 500/1000 mA cm-2 at ultralow cell voltages of 1.62/1.66 V for overall water electrolysis with outstanding long-term stability are actualized. More interestingly, this hybrid catalyst also performs well in acidic, neutral freshwater, and seawater requiring relatively low overpotentials of 140, 290, and 331 mV to reach 500 mA cm-2. Particularly, this catalyst can withstand electrochemical corrosion without obvious activity decay at the industrial-level current densities for over 100 h in base. This work provides a cornerstone for the construction of advanced catalysts operated in different pH environments.
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Developing efficient metal-free catalysts to directly synthesize hydrogen peroxide (H2O2) through a 2-electron (2e) oxygen reduction reaction (ORR) is crucial for substituting the traditional energy-intensive anthraquinone process. Here, in-plane topological defects enriched graphene with pentagon-S and pyrrolic-N coordination (SNC) is synthesized via the process of hydrothermal and nitridation. In SNC, pentagon-S and pyrrolic-N originating from thiourea precursor are covalently grafted onto the basal plane of the graphene framework, building unsymmetrical dumbbell-like SâCâN motifs, which effectively modulates atomic and electronic structures of graphene. The SNC catalyst delivers ultrahigh H2O2 productivity of 8.1, 7.3, and 3.9 mol gcatalyst -1 h-1 in alkaline, neutral, and acidic electrolytes, respectively, together with long-term operational stability in pH-universal electrolytes, outperforming most reported carbon catalysts. Theoretical calculations further unveil that defective SâCâN motifs efficiently optimize the binding strength to OOH* intermediate and substantially diminish the kinetic barrier for reducing O2 to H2O2, thereby promoting the intrinsic activity of 2e-ORR.
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The key dilemma for green hydrogen production via electrocatalytic water splitting is the high overpotential required for anodic oxygen evolution reaction (OER). Co/Fe-based materials show superior catalytic OER activity to noble metal-based catalysts, but still lag far behind the state-of-the-art Ni/Fe-based catalysts probably due to undesirable side segregation of FeOOH with poor conductivity and unsatisfied structural durability under large current density. Here, a robust and durable OER catalyst affording current densities of 500 and 1000 mA cm-2 at extremely low overpotentials of 290 and 304 mV in base is reported. This catalyst evolves from amorphous bimetallic FeOOH/Co(OH)2 heterostructure microsheet arrays fabricated by a facile mechanical stirring strategy. Especially, in situ X-ray photoelectron spectroscopy (XPS) and Raman analysis decipher the rapid reconstruction of FeOOH/Co(OH)2 into dynamically stable Co1-x Fex OOH active phase through in situ iron incorporation into CoOOH, which perform as the real active sites accelerating the rate-determining step supported by density functional theory calculations. By coupling with MoNi4 /MoO2 cathode, the self-assembled alkaline electrolyzer can deliver 500 mA cm-2 at a low cell voltage of 1.613 V, better than commercial IrO2 (+) ||Pt/C(-) and most of reported transition metal-based electrolyzers. This work provides a feasible strategy for the exploration and design of industrial water-splitting catalysts for large-scale green hydrogen production.
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Wound healing is a dynamic and complex process in which the microenvironment at the wound site plays an important role. As a common material for wound healing, dressings accelerate wound healing and prevent external wound infections. Hydrogels have become a hot topic in wound-dressing research because of their high water content, good biocompatibility, and adjustable physical and chemical properties. Intelligent hydrogel dressings have attracted considerable attention because of their excellent environmental responsiveness. As smart polymer hydrogels, thermosensitive hydrogels can respond to small temperature changes in the environment, and their special properties make them superior to other hydrogels. This review mainly focuses on the research progress in thermosensitive intelligent hydrogel dressings for wound healing. Polymers suitable for hydrogel formation and the appropriate molecular design of the hydrogel network to achieve thermosensitive hydrogel properties are discussed, followed by the application of thermosensitive hydrogels as wound dressings. We also discuss the future perspectives of thermosensitive hydrogels as wound dressings and provide systematic theoretical support for wound healing.
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Developing efficient and robust hydrogen evolution reaction (HER) catalysts for scalable and sustainable hydrogen production through electrochemical water splitting is strategic and challenging. Herein, heterogeneous Mo8 O26 -NbNx Oy supported on N-doped graphene (defined as Mo8 O26 -NbNx Oy /NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O-exposed Mo8 O26 clusters covalently confined on NbNx Oy nanodomains provide a distinctive interface configuration and appropriate electronic structure, where fully exposed multiple active sites give excellent HER performance beyond commercial Pt/C catalyst in pH-universal electrolytes. Theoretical studies reveal that the Mo8 O26 -NbNx Oy interface with electronic reconstruction affords near-optimal hydrogen adsorption energy and enhanced initial H2 O adsorption. Furthermore, the terminal O atoms in Mo8 O26 clusters cooperate with Nb atoms to promote the initial H2 O adsorption, and subsequently reduce the H2 O dissociation energy, accelerating the entire HER kinetics.
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Seawater is the most abundant natural water resource in the world, which is an inexhaustible and low-cost feedstock for hydrogen production by alkaline water electrolysis. It is appearling to develop robust and stable electrocatalysts for alkaline seawater electrolysis. However, the development of seawater electrolysis is seriously impeded by anodic chloride corrosion and chlorine evolution reaction, and few non-noble electrocatalysts show prominent catalytic performance and excellent durability. Here, a heterogeneous electrocatalyst constructed by in situ growing highly dispersed iron-rich bimetallic phosphide nanoparticles on metallic Ni3 N (Fe2-2 x Co2 x P/Ni3 N), which exhibits outstanding bifunctional catalytic activities for alkaline seawater splitting, is reported. The optimal (Fe0.74 Co0.26 )2 P/Ni3 N and Fe2 P/Ni3 N electrocatalysts demand only 113 and 212 mV to afford 100 mA cm-2 for hydrogen and oxygen evolution reactions (HER and OER) in 1 m KOH, respectively, thus substantially expediting overall water/seawater electrolysis at 100 mA cm-2 with 1.592/1.645 V. Particularly, Fe2 P/Ni3 N displays an unprecedented overpotential of 302 mV at 500 mA cm-2 , which represents the best alkaline seawater oxygen evolution activity among the ever-reported non-noble electrocatalysts; and thus substantially expedites overall water/seawater splitting at 500 mA cm-2 with 1.701/1.768 V, surpassing most of the reported non-noble lectrocatalysts. This work provides a new approach for developing high-performance electrocatalysts for seawater splitting.
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Given the abundant reserves of seawater and the scarcity of freshwater, real seawater electrolysis is a more economically appealing technology for hydrogen production relative to orthodox freshwater electrolysis. However, this technology is greatly precluded by the undesirable chlorine oxidation reaction and severe chloride corrosion at the anode, further restricting the catalytic efficiency of overall seawater splitting. Herein, a feasible strategy by engineering multifunctional collaborative catalytic interfaces is reported to develop porous metal nitride/phosphide heterostructure arrays anchoring on conductive Ni2P surfaces with affluent iron sites. Collaborative catalytic interfaces among iron phosphide, bimetallic nitride, and porous Ni2P supports play a positive role in improving water adsorption/dissociation and hydrogen adsorption behaviors of active Fe sites evidenced by theoretical calculations for hydrogen evolution reactions, and enhancing oxygenated species adsorption and nitrate-rich passivating layers resistant to chloride corrosion for oxygen evolution reaction, thus cooperatively propelling high-performance bifunctional seawater splitting. The resultant material Fe2P/Ni1.5Co1.5N/Ni2P performs excellently as a self-standing bifunctional catalyst for alkaline seawater splitting. It requires extremely low cell voltages of 1.624 and 1.742 V to afford current densities of 100 and 500 mA/cm2 in 1 M KOH seawater electrolytes, respectively, along with superior long-term stability, outperforming nearly all the ever-reported non-noble bifunctional electrocatalysts and benchmark Pt/IrO2 coupled electrodes for freshwater/seawater electrolysis. This work presents an effective strategy for greatly enhancing the catalytic efficiency of non-noble catalysts toward green hydrogen production from seawater electrolysis.
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Earth-abundant layered tungsten disulfide (WS2 ) is a well-known electrocatalyst for acidic hydrogen evolution, but it becomes rather sluggish for alkaline hydrogen or oxygen evolution due to the low-density edge sites, poor conductivity, and unfavorable water dissociation behavior. Here, an interfacial engineering strategy to construct an efficient bifunctional electrocatalyst by in situ growing N-doped WS2 nanoparticles on highly conductive cobalt nitride (N-WS2 /Co3 N) for concurrent hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) is demonstrated. Benefiting from the good conductivity of Co3 N, rich well-oriented edge sites and water-dissociation sites at the nanoscale interfaces between N-WS2 and Co3 N, the resultant N-WS2 /Co3 N exhibits remarkable HER activity in 1 m potasium hydroxide (KOH) requiring a small overpotential of 67 mV at 10 mA cm-2 with outstanding long-term durability at 500 mA cm-2 , representing the best alkaline hydrogen-evolving activity among reported WS2 catalysts. In particular, this hybrid catalyst also shows exceptional catalytic activities toward theurea oxidation reaction featured by very low potentials of 1.378 and 1.41 V to deliver 100 and 500 mA cm-2 along with superb large-current stability in 1 m KOH + 0.5 m urea. Moreover, the assembled two-electrode cell delivers the industrially practical current density of 500 mA cm-2 at a low cell voltage of 1.72 V with excellent durability in alkaline urea-containing solutions, outperforming most MoS2 -like bifunctional electrocatalysts for overall water splitting reported hitherto. This work provides a promising avenue for the development of high-performance WS2 -based electrocatalysts for alkaline water splitting.
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Hydrogels are investigated broadly in flexible sensors which have been applied into wearable electronics. However, further application of hydrogels is restricted by the ambiguity of the sensing mechanisms, and the multi-functionalization of flexible sensing systems based on hydrogels in terms of cost, difficulty in integration, and device fabrication remains a challenge, obstructing the specific application scenarios. Herein, cost-effective, structure-specialized and scenario-applicable 3D printing of direct ink writing (DIW) technology fabricated two-dimensional (2D) transition metal carbides (MXenes) bonded hydrogel sensor with excellent strain and temperature sensing performance is developed. Gauge factor (GF) of 5.7 (0 - 191% strain) and high temperature sensitivity (-5.27% °C-1) within wide working range (0 - 80 °C) can be achieved. In particular, the corresponding mechanisms are clarified based on finite element analysis and the first use of in situ temperature-dependent Raman technology for hydrogels, and the printed sensor can realize precise temperature indication of shape memory solar array hinge.
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Alkaline water electrolysis is an advanced technology for scalable H2 production using surplus electricity from intermittent energy sources, but it remains challenging for non-noble electrocatalysts to split water into hydrogen and oxygen efficiently, especially for tungsten disulfide (WS2 )-based catalysts. Density functional theory calculations in combination with experimental study are used to establish a multi-site engineering strategy for developing robust WS2 -based hybrid electrocatalyst on mesoporous bimetallic nitride (Ni3 FeN) nanoarrays for bifunctional water splitting. This ingenious design endows the catalyst with numerous edge sites chemically bonded with the conductive scaffold, which are favorable for water dissociation and hydrogen adsorption. Benefiting from the synergistic advantages, the N-WS2 /Ni3 FeN hybrid exhibits exceptional bifunctional properties for hydrogen and oxygen evolution reactions (HER and OER) in base with excellent large-current durability, requiring 84 mV to afford 10 mA cm-2 for HER, and 240 mV at 100 mA cm-2 for OER, respectively. Assembling the catalytic materials as both the anode and cathode to construct an electrolyzer, it is actualized very good activities for overall water splitting with only 1.5 V to deliver 10 mA cm-2 , outperforming the IrO2 (+) //Pt(-) coupled electrodes and many non-noble bifunctional electrocatalysts thus far. This work provides a promising avenue for designing WS2 -based heterogeneous electrocatalysts for water electrolysis.
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The catalytic hydrogen-evolving activities of transition-metal phosphides are greatly related to the phosphorus content, but the physical origin of performance enhancement remains ambiguous, and tuning the catalytic activity of nickel phosphides (NiP2 /Ni5 P4 ) remains challenging due to unfavorable H* adsorption. Here, a strategy is introduced to integrate P-rich NiP2 and P-poor Ni5 P4 into in-plane heterostructures by anion substitution, in which P atoms at the in-plane interfaces perform as active sites to adsorb H* and thus facilitate the hydrogen evolution reaction (HER) process via modulating the electronic structure between NiP2 and Ni5 P4 . Consequently, the NiP2 /Ni5 P4 hybrid exhibits an outstanding hydrogen-evolving activity, requiring only 30 and 76 mV to afford 10 and 100 mA cm-2 in acid, respectively. It surpasses most of the earth-abundant electrocatalysts thus far, and is comparable to Pt catalysts (30/72 mV at 10/100 mA cm-2 ). Particularly, it can run smoothly at large current density and only requires 247 mV to reach 2000 mA cm-2 . Detailed theoretical calculations reveal that its exceptional activity stems from the moderate overlap of density states between P 2p and H 1s orbitals, thus optimizing the H*-adsorption strength. This work highlights a new avenue toward the fabrication of robust non-noble electrocatalysts by constructing in-plane heterojunctions.
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BACKGROUND: The present study is aimed at evaluating the functional and clinical values of P3H4 in lung adenocarcinoma. Moreover, we also investigated the downstream pathways that P3H4 might participate in. METHODS: The differential expression analysis was used to identify genes differentially expressed in lung adenocarcinoma tissues as compared with normal tissues. Survival analysis was used to test the association between P3H4 and survival time. Gene set enrichment analysis was conducted to explore the downstream pathways. CCK8 and transwell were employed to examine the impact of P3H4 on cell phenotypes. RESULTS: P3H4 was highly upregulated in LUAD tissues at both RNA and protein levels. Moreover, the LUAD patients, who had high expression of P3H4, were also observed to have shorter disease-free survival and overall survival. These results demonstrated that P3H4 could be used as a prognostic biomarker for LUAD. Moreover, we also found that it was the copy number alterations (CNAs), not DNA methylation, that regulated the RNA expression of P3H4, indicating that its upregulation might be partially resulted from the CNAs. Furthermore, functional experiments revealed that the A549 and H1299 cells with siRNA treatment (siP3H4) exhibited significantly decreased cell proliferation after 24 hours, migratory ability, and invasiveness. Functionally, the upregulated proteins in the P3H4 high expression group were mainly enriched in tumor microenvironment-related pathways such as phagosome, focal adhesion, and ECM-receptor interaction and cancer-related pathways such as bladder cancer pathway, proteoglycans in cancer, and hippo signaling pathway. CONCLUSION: The present study systematically evaluated the functional and clinical values of P3H4 in LUAD, and explored the related biological pathways. P3H4 might promote LUAD progression through regulating tumor microenvironment-related pathways.
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Adenocarcinoma de Pulmão/genética , Autoantígenos/genética , Neoplasias Pulmonares/genética , Células A549 , Adenocarcinoma de Pulmão/metabolismo , Adenocarcinoma de Pulmão/mortalidade , Autoantígenos/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Biologia Computacional , Variações do Número de Cópias de DNA , Metilação de DNA , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Inativação Gênica , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/mortalidade , Invasividade Neoplásica/genética , Prognóstico , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , RNA Interferente Pequeno/genética , Transdução de Sinais/genética , Microambiente Tumoral/genética , Regulação para CimaRESUMO
Emerging evidence proves that exosomes contain specific microRNAs(miRNAs) contribute to osteogenic differentiation of bone marrow stem cells (BMSCs). However, the role and mechanism of bone marrow stem cells (BMSCs)-derived exosomes overexpressing miR-424-5p in osteoblasts remains unclear. Firstly, the BMSCs-derived exosomes were isolated, and identified by Western blot with the exosome surface markers CD9, CD81 and CD63. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect the level of miR-424-5p in exosomes, and western blot was implemented to verify the WIF1/Wnt/ß-catenin expression. The binding association between miR-424-5p and WIF1 was determined by the dual-luciferase reporter gene assay. Functional enhancement experiments were adopted to determine the role of exosome-carried miR-424-5p and WIF1/Wnt/ß-catenin in osteogenic differentiation. ALP staining was adopted, and levels of RUNX2, OCN, and OPN were monitored using qRT-PCR to determine osteogenic differentiation. As a result, In vivo experiments showed that RUNX2, OCN and OPN levels decreased and the ALP activity was dampened after miR-424-5p overexpression in exosomes. Besides, exosomes overexpressing miR-424-5p attenuated osteogenic development via WIF1/Wnt/ß-catenin. Our findings may bring evidence for miR-424-5p as a new biomarker for the treatment of osteoporosis.
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Proteínas Adaptadoras de Transdução de Sinal/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Exossomos/metabolismo , MicroRNAs/genética , Osteoblastos/metabolismo , Osteogênese/genética , Células-Tronco/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Humanos , Osteocalcina/genéticaRESUMO
Obesity is not only closely related to insulin resistance but is one of the main factors leading to the formation of Type 2 Diabetes (T2D) too. The c-Jun N-terminal kinase (JNK) family is a member of the mitogen-activated protein kinase (MAPK) superfamily. JNK is also one of the most investigated signal transducers in obesity and insulin resistance. JNK-centric JNK signaling pathway can be activated by growth factors, cytokines, stress responses, and other factors. Many researches have identified that the activated phosphorylation JNK negatively regulates insulin signaling pathway in insulin resistance which can be simultaneously regulated by multiple signaling pathways related to the JNK signaling pathway. In this review, we provide an overview of the composition of the JNK signaling pathway, its regulation of insulin signaling pathway, and the relationship between the JNK signaling pathway and other pathways in insulin resistance.
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Developing efficient non-noble and earth-abundant hydrogen-evolving electrocatalysts is highly desirable for improving the energy efficiency of water splitting in base. Molybdenum disulfide (MoS2 ) is a promising candidate, but its catalytic activity is kinetically retarded in alkaline media due to the unfavorable water adsorption and dissociation feature. A heterogeneous electrocatalyst is reported that is constructed by selenium-doped MoS2 (Se-MoS2 ) particles on 3D interwoven cobalt diselenide (CoSe2 ) nanowire arrays that drives the hydrogen evolution reaction (HER) with fast reaction kinetics in base. The resultant Se-MoS2 /CoSe2 hybrid exhibits an outstanding catalytic HER performance with extremely low overpotentials of 30 and 93 mV at 10 and 100 mA cm-2 in base, respectively, which outperforms most of the inexpensive alkaline HER catalysts, and is among the best alkaline catalytic activity reported so far. Moreover, this hybrid catalyst shows exceptional catalytic performance with very low overpotentials of 84 and 95 mV at 10 mA cm-2 in acidic and neutral electrolytes, respectively, implying robust pH universality of this hybrid catalyst. This work may provide new inspirations for the development of high-performance MoS2 -based HER electrocatalysts in unfavorable basic media for promising catalytic applications.
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The photoreduction of CO2 to hydrocarbon products has attracted much attention because it provides an avenue to directly synthesize value-added carbon-based fuels and feedstocks using solar energy. Among various photocatalysts, graphitic carbon nitride (g-C3N4) has emerged as an attractive metal-free visible-light photocatalyst due to its advantages of earth-abundance, nontoxicity, and stability. Unfortunately, its photocatalytic efficiency is seriously limited by charge carriers' ready recombination and their low reaction dynamics. Modifying the local electronic structure of g-C3N4 is predicted to be an efficient way to improve the charge transfer and reaction efficiency. Here, boron (B) is doped into the large cavity between adjacent tri-s-triazine units via coordination with two-coordinated N atoms. Theoretical calculations prove that the new electron excitation from N (2p x , 2p y ) to B (2p x , 2p y ) with the same orbital direction in B-doped g-C3N4 is much easier than N (2p x , 2p y ) to C 2p z in pure g-C3N4, and improves the charge transfer and localization, and thus the reaction dynamics. Moreover, B atoms doping changes the adsorption of CO (intermediate), and can act as active sites for CH4 production. As a result, the optimal sample of 1%B/g-C3N4 exhibits better selectivity for CH4 with ≈32 times higher yield than that of pure g-C3N4.
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Facile design of low-cost and high-efficiency catalysts with earth-abundant and cheap materials is desirable to replace platinum (Pt) for the hydrogen evolution reaction (HER) in water splitting, but the development of such HER catalysts with Pt-like activity using simple strategies remains challenging. A mesoporous hybrid catalyst of nickel phosphides nanoparticles and cobalt phosphosulfide/phosphide (CoS|Ni|P) nanosheet arrays for HER is reported here, which is developed by a facile three-step approach consisting of electrodeposition, thermal sulfurization, and phosphorization. This hybrid catalyst is highly robust and stable in acid for HER, and is distinguished by very low overpotentials of 41, 88, and 150 mV to achieve 10, 100, and 1000 mA cm-2 , respectively, as well as a small Tafel slope (45.2 mV dec-1 ), and a large exchange current density (964 µA cm-2 ). It is among the most efficient earth-abundant catalysts reported thus far for HER. More importantly, this electrocatalyst has electrochemical durability over 20 h under a wide range of current densities (up to 1 A cm-2 ) in acidic conditions, as well as very high turnover frequencies of 0.40 and 1.26 H2 s-1 at overpotentials of 75 and 100 mV, respectively, showing that it has great potential for practical applications in large-scale water electrolysis.