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Designing a high-performing iridium (Ir) single-atom catalyst is desired for acidic water electrolysis, which shows enormous potential given its high catalytic activity toward acidic oxygen evolution reaction (OER) with minimum usage of precious Ir metal. However, it still remains a substantial challenge to stabilize the Ir single atoms during the OER operation without sacrificing the activity. Here, we report a high-performing OER catalyst by immobilizing Ir single atoms on a polyimide support, which exhibits a high mass activity on a carbon paper electrode while simultaneously achieving outstanding stability with negligible decay for 360 h. The resulting electrode (denoted as Ir1–PI@CP) reaches a 49.7-fold improvement in mass activity compared to the counterpart electrode prepared without polyimide support. Both our experimental and theoretical results suggest that, owing to the strong metal–support interactions, the polyimide support can enhance the Ir 5d states of Ir single atoms in Ir1–PI@CP, which can tailor the adsorption energies of intermediates and decrease the thermodynamic barrier at the rate-determining step of the OER, but also facilitate the proton–electron-transfer process and improve the reaction kinetics. This work offers an alternative avenue for developing single-atom catalysts with superior activity and durability toward various catalytic systems and beyond.

Platinum (Pt) is the state-of-the-art electrocatalyst for anodic hydrogen oxidation reaction (HOR) in proton exchange membrane fuel cells (PEMFCs). However, a critical drawback of PEMFCs is the extreme sensitivity of Pt catalyst to CO (impurity in industrial hydrogen), which markedly damages the device’s performance. Therefore, enhancing the CO-tolerant performance of Pt catalysts is crucial for the commercialization of PEMFCs. Herein, we constructed PtNiW@amorphous WOxcore-shell nanowires to improve the CO-tolerance of Pt. Mechanistically, it is demonstrated that the surface amorphous WOxshell can kinetically hinder the accessibility of CO over Pt sites by acting as a selective molecular-sieving layer. Besides, thermodynamically, the electronic effect from the alloying of Ni and W elements could weaken the CO adsorption on Pt sites by downshifting the d-band center. In addition, the oxyphilic W elements can accelerate the dissociation of water to provide more OH species, promoting the oxidation of CO. As a consequence, the as-designed PtNiW@WOxNWs can maintain over 90% HOR current density after 4000 s in 1000 ppm CO/H2, exceeding most of the Pt-based catalysts reported ever.

Electrochemical oxidation of ethylene is a novel approach to manufacture valuable ethylene glycol (EG), which is an important raw material in organic chemical industry. However, the poor EG selectivity and expensive additional purification costs hinder this method from being practically used. In this work, ultrafine iridium-ruthenium (IrRu) alloy nanoparticles are synthesized through the precipitation-reduction method and their electrocatalytic performance towards ethylene oxidation to EG has been comprehensively studied. Near 100% selectivity is achieved with a EG yield of 60.62 mmol gRu−1h−1at 1.475 V on an optimal Ir0.54Ru0.46catalyst. OH-stripping, in-situelectrochemical attenuated total internal reflectance Fourier transform infrared spectra and DFT calculation reveal that the introduction of Ir can modulate the electronic structure and d-band center so as to endow the Ru with the mild binding energy with the key intermediates and small energy barrier for *HOCH2CH2OH desorption, thereby enhancing the EG generation. Simultaneously, the high energy barrier for the overoxidation of the *CH2CH2OH renders the EG formation thermodynamically favorable, thus realizing the near 100% EG selectivity. This work provides a new understanding for the high-selectivity electrosynthesis of high-value-added oxides.

In order to evaluate the influence of defects on the performance of Micro‐LED devices, this paper adopts a finite element simulation method based on semiconductor physics. Firstly, a simulation model of Micro‐LED devices is established, including key components such as electrodes, materials, and structures. Then, defect parameters are set to simulate the optical properties of Micro‐LED devices. Finally, by comparing the simulation results with or without introducing deep level defects, the influence law of these defects on the optical output and electrical characteristics of Micro‐LED devices was revealed.

Ni-rich layered metal oxide cathodes and extreme fast charging (XFC) protocol have been introduced into lithium-ion batteries for the wider adoption of various electric devices. However, nickel intensifies electrolyte decomposition and XFC poses challenges due to extremely high current density. Based on the characterization paradigm established in our previous work, our findings reveal a fundamental difference in the decomposition pathway of the electrolyte under XFC conditions compared to the enhanced reactivity between the oxide and electrolyte caused by Ni content. Specifically, Ni catalyzes solvent dehydrogenation, leading to the formation of protic species that can attack the intermediate, PF5, thereby promoting the decomposition/hydrolysis of LiPF6. But in XFC conditions, the reaction time of dehydrogenation conducted at high voltages is significantly reduced, while conversion of LiPF6to PF5lasts throughout the discharging process. Greater accumulation of PF5as a new initiator changes the solvent decomposition pathway, leading to different cathode–electrolyte interface layers.

Improving the complete ethanol electrooxidation on Pd-based catalysts in alkaline media has drawn widely attention due to the high mass energy density. However, the weak adsorption energy of CH3CO* on Pd restricts the C-C bond cleavage. Inspired by the molecular orbital theory, we proposed the d-state-editing strategy to construct more unoccupied d-states of Pd for the enhanced interaction with CH3CO* to break C-C bonds. As expected, the reduced number of egelectrons and more unoccupied d-states of Pd successfully formed on as-prepared porous RhAu-PdCu nanosheets (PNSs). Theoretical calculations show that the optimized d-states of RhAu-PdCu PNS can effectively improve the adsorption of CH3CO* and drastically reduce the energy barrier of C-C bond cleavage, thus boosting the complete oxidation of ethanol. The charge ratio of C1pathway on RhAu-PdCu PNSs is 51.5%, more than 2 times higher than that of Pd NSs. Our finding provides an innovative perspective for the design of highly-efficient noble-based electrocatalysts.

The etch damage caused by the conventional bench-top etching process makes it difficult to produce Nano-LED devices. Recently, some scholars have studied the use of ion injection to achieve electrical isolation between pixels for the purpose of pixelation. In this paper, we focus on the distribution characteristics of ions in GaN targets to improve the effective light-emitting area ratio of devices by reducing the lateral diffusion effect of ions.

Adverse effects of nanoparticles (NPs) on biological nitrogen removal (BNR) systems have been extensively explored. However, little information is available on the system's resistance capacity and its improvement strategy to NP stress. We systematically investigated the effects and mechanisms of exogenous N-acyl-homoserine lactones (AHLs) with three different acyl-side chain lengths (N-hexanoyl-l-homoserine lactone (C6-HSL), N-decanoyl-l-HSL and N-tetradecanoyl-dl-HSL) at different concentrations on the resistance of Nitrosomonas europaeato acute CeO2NP stress. All three AHLs promoted the NP-stressed cellular viabilities, ammonia oxidation performances, and superoxide dismutase activities. The required AHL dose to achieve the optimal anti-toxicity performance depended on its type. The shorter the acyl-side chain length, the lower the optimal acting concentration needed. 0.01 μM C6-HSL achieved the best cellular resistance capacity to CeO2NP stress. The stimulations of the sulfate transport and metabolism in the presence of C6-HSL promoted the posttranslational modification related to the Fe–S cluster assembly, thus stimulating the electron transfer and aerobic respiration, which synergized with the facilitated ribosomal protein biosynthesis to improve the stressed cellular growth. Meanwhile, the activation of phospholipid transport and chaperone participation related to stress resistance maintained the membrane homeostasis that was actively involved in the promotion of the cellular resistance to NP stress. These findings would inspire a feasible strategy development of AHL-based QS regulation to alleviate NP stress for impaired BNR systems.

In this paper, we describe the synthesis of the AC-PtNi/G catalysts with graphene as the carrier, viathe alcohol reduction and the sulfuric acid treatment. The prepared catalysts were microscopically characterized by X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), electron spectroscopy(EDAX), and transmission electron micros-copy(TEM). We tested the electrochemical performance of the prepared catalysts using an electrochemical workstation and in situinfrared spectroscopy(FTIR). The results showed that the acid-treated AC-PtNi/G catalysts had a more uniform dispersion and with the increased of treatment time, the particle size of the catalyst became smaller. And the electrocatalytic performance of the AC-PtNi/G-48h catalyst treated with sulfuric acid for 48 h was significantly better than that of the untreated PtNi/G catalyst. Its electrochemically active surface area was 76.63 m2/g, and the peak current density value for catalytic oxidation of ethanol was 1218.83 A/g, which was 10 times that of ordinary commercial Pt/C catalyst. The steady-state current density value of 1100 s was 358.77 A/g, and it has excellent anti-CO toxicity performance. It was determined that a sulfuric acid treatment controlled catalyst particle size and increased the electrocatalytic activity of the catalytic oxidation of ethanol.

Atomic edge sites on two-dimensional (2D) nanomaterials display striking catalytic behavior, whereas edge engineering for 2D metal nanocatalysts remains an insurmountable challenge. Here we advance a one-pot synthesis of ultrathin 2D PdPtCu trimetallic nanosheets and nanorings with escalating low-coordinated edge proportions from 11.74% and 23.11% to 45.85% as cutting-edge ethanol oxidation reaction (EOR) electrocatalysts. This in situ edge enrichment hinges on a competitive surface capping and etching strategy with integrated manipulation of the reaction kinetics. Electrocatalysis tests demystify an edge-relied EOR performance, where the edge-richest 9.0 nm-Pd61Pt22Cu17nanorings attain an exceptional activity (12.42 A mg–1Pt+Pd, 20.2 times that of commercial Pt/C) with substantially improved durability. Molecularly mechanistic studies certify that the unsaturated edge sites on these 2D catalysts prevail, triggering the C–C bond scission and succeeding CO removal to facilitate a 12-electron-transferring EOR process. This study introduces the “metal-edge-driven” concept and enables the “edge sites on 2D multimetallic nanocatalysts” technique to design versatile heterocatalysts.

To meet the requirements of potential applications, it is of great importance to explore new catalysts for formic acid oxidation that have both ultra-high mass activity and CO resistance. Here, we successfully synthesize atomically dispersed Rh on N-doped carbon (SA-Rh/CN) and discover that SA-Rh/CN exhibits promising electrocatalytic properties for formic acid oxidation. The mass activity shows 28- and 67-fold enhancements compared with state-of-the-art Pd/C and Pt/C, respectively, despite the low activity of Rh/C. Interestingly, SA-Rh/CN exhibits greatly enhanced tolerance to CO poisoning, and Rh atoms in SA-Rh/CN resist sintering after long-term testing, resulting in excellent catalytic stability. Density functional theory calculations suggest that the formate route is more favourable on SA-Rh/CN. According to calculations, the high barrier to produce CO, together with the relatively unfavourable binding with CO, contribute to its CO tolerance.

Two-dimensional (2D) heterojunction nanomaterials offer exceptional physicochemical and catalytic properties, thanks to their special spatial electronic structure. However, synthesizing morphologically uniform 2D platinum (Pt)-based metallic nanomaterials with diverse crystalline phases remains a formidable challenge. In this study, we have achieved the successful synthesis of advanced 2D platinum–tellurium heterojunction nanosheet assemblies (Ptx–PtTe2HJNSAs, x= 0, 1, 2), seamlessly integrating both trigonal PtTe2(t-PtTe2) and cubic Pt (c-Pt) phases. By enabling efficient electron transport and leveraging the specific electron density present at the heterojunction, the Pt2–PtTe2HJNSAs/C demonstrated exceptional formic acid oxidation reaction (FAOR) activity and stability. Specifically, the specific and mass activities reached 8.4 mA cm–2and 6.1 A mgPt–1, which are 46.7 and 50.8 times higher than those of commercial Pt/C, respectively. Impressively, aberration-corrected high-angle annular dark field scanning transmission electron microscopy (AC-HAADF-STEM) revealed a closely packed arrangement of atomic layers and a coherent intergrowth heterogeneous structure. Density functional theory (DFT) calculations further indicated that rearrangement of electronic structure occurred on the surface of Pt2–PtTe2HJNSAs resulting in a more favorable dehydrogenation pathway and excellent CO tolerance, beneficial for performance improvement. This work inspires the targeted exploration of Pt-based nanomaterials through 2D heterostructure design, leading to an important impact on fuel cell catalysis and beyond.

Direct borohydride fuel cell (DBFC) is considered a promising energy storage device due to its high theoretical cell voltage and energy density. For DBFC, an Au catalyst has been used as an anode for achieving an ideal eight-electron reaction. However, the poor activity of the Au catalyst for borohydride oxidation reaction (BOR) limits its large-scale application because of the weak BH4–adsorption. We found, by density functional theory calculations, that the adsorption of BH4–on the oxidized Au surface is stronger than that on the metallic Au surface, which can promote the process of the oxidation of BH4–to *BH3during the BOR. Here, we reported an oleylamine-modified partially oxidized Au supported on carbon powder (AuC-OLA) with a stable oxidation state. The obtained catalyst delivered a high peak power density of 143 mW/cm2, which is 2 times higher than that of a commercial 40% AuC (Pretemek). The in situ Fourier transform infrared studies showed that the activity of AuC-OLA for BOR is ascribed to the enhanced adsorption for BH4–on the partially oxidized Au surface. These findings will promote the reasonable design of efficient Au electrocatalysts for DBFCs.

Electrocatalytic nitrogen oxidation reaction (NOR) can convert nitrogen (N2) into nitrate (NO3–) under ambient conditions, providing an attractive approach for synthesis of NO3–, alternative to the current approach involving the harsh Haber–Bosch and Ostwald oxidation processes that necessitate high temperature, high pressure, and substantial carbon emission. Developing efficient NOR catalysts is a prerequisite, which remains a formidable challenge, owing to the weak activation/dissociation of N2. A variety of NOR electrocatalysts have been developed, but their NOR kinetics are still extremely sluggish, resulting in inferior Faradaic Efficiencies. Here, we report a high-entropy Ru-based perovskite oxide (denoted as Ru-HEP) that can function as a high-performance NOR catalyst and exhibit a high NO3–yield rate of 39.0 μmol mg–1h–1with a Faradaic Efficiency of 32.8%. Both our experimental results and theoretical calculations suggest that the high-entropy configuration of Ru-HEP perovskite oxide can markedly enhance the oxygen-vacancy concentration, where the Ru sites and their neighboring oxygen vacancies can serve as unsaturated centers and decrease the overall energy barrier for N2electrooxidation, thereby leading to promoted NOR kinetics. This work presents an alternative avenue for promoting NOR catalysis on perovskite oxides through the high-entropy engineering strategy.

Pd-based nanoparticles are considered as the most promising electrocatalysts for ethanol oxidation reaction (EOR) in alkaline direct ethanol fuel cells (DEFCs). However, the existing catalysts still suffer from insufficient intrinsic activity and poor durability. Herein, we combine two strategies of both surface structure control and surface modification to enhance the performance of Pd-based electrocatalysts. A series of Au-decorated tetrahexahedral Pd nanocrystals (Au/THH Pd NCs) with {310} high-index facets and controllable Au coverages (θAu) were prepared, and their surface properties have been thoroughly characterized. Electrochemical characterizations indicate that Au deposits evenly on the surface of THH Pd NCs by galvanic replacement. XPS analysis and DFT calculations suggest that the decoration of Au from galvanic replacement can promote the surface reactivity of Pd, which is evidenced by the upshift of the d-band center of Pd. In situFTIR spectra of adsorbed CO also confirm the stronger binding of CO on Pd upon Au decoration. The electrocatalytic activity of the Au/THH Pd NCs for EOR is significantly enhanced along with alteration of surface structure and is ranked as Au/THH Pd NCs > THH Pd NCs > Pd black. Especially when θAu= 0.38, the catalytic activity of the Au/THH Pd NCs is around 4 and 20 times of the THH Pd NCs and the Pd black, respectively. The reaction mechanism revealed by in situFTIR spectroscopic studies has confirmed that Au modification could further speed up the oxidation rate of ethanol to acetate. The findings gained in the present study extend fundamental understanding on the surface structure effects of nanoparticle catalysts and cast new light on exploration of superior EOR electrocatalysts.

Architectural engineering of noble metal nanocrystals can result in structural diversity and complexity, thereby providing catalysts with multifunctional properties. Herein, a unique Sierpinski gasket-like Pt–Ag octahedral alloy nanostructure with a three-dimensional hyperbranched architecture containing abundant well-defined Pt-rich {111} stable facets and dense low-coordinated active sites is reported. Unlike the well-accepted long-range limiting diffusion govened growth model for fractal structures, our success relies on creating local depletion layer near the crystal surface by surfactant. The as-prepared Sierpinski gasket-like Pt–Ag octahedral nanocrystals allows us to achieve three milestones for electrocatalysts, i.e. high catalytic activity, great durability, and stability towards the methanol oxidation reaction in acidic media. Specifically, the catalyst shows a high specific activity (6.61 mA cm−2, is superior than most of reported Pt-based catalysts), outstanding COads-poisoning tolerance and stability (the morphology and composition of the catalyst are preserved after 2000 cycles). This study points to a new approach to develop highly efficient catalysts in the form of fractal nanostructures with structural diversity and complexity to balance the delicate trade-off between activity and stability of catalysts.

Abstract Porous carbon materials were prepared by hydrothermal carbonization (HTC) and KOH activation of camphor leaves and camellia leaves. The morphology, pore structure, chemical properties and CO 2 capture ability of the porous carbon prepared from the two leaves were compared. The effect of HTC temperature on the structure and CO 2 adsorption properties was especially investigated. It was found that HTC temperature had a major effect on the structure of the product and the ability to capture CO 2. The porous carbon materials prepared from camellia leaves at the HTC temperature of 240 °C had the highest proportion of microporous structure, the largest specific surface area (up to 1823.77 m2/g) and the maximum CO 2 adsorption capacity of 8.30 mmol/g at 25 °C under 0.4 MPa. For all prepared porous carbons, simulation results of isothermal adsorption model showed that Langmuir isotherm model described the adsorption equilibrium data better than Freundlich isotherm model. For porous carbons prepared from camphor leaves, pseudo-first order kinetic model was well fitted with the experimental data. However, for porous carbons prepared from camellia leaves, both pseudo-first and pseudo-second order kinetics model adsorption behaviors were present. The porous carbon materials prepared from tree leaves provided a feasible option for CO 2 capture with low cost, environmental friendship and high capture capability. [ABSTRACT FROM AUTHOR]

Direct ethanol fuel cells are a type of promising energy conversion device with high energy density, and their commercialization is still impeded by incomplete oxidation of ethanol on available electrocatalysts. Herein, a kind of novel excavated Rhodium (Rh) nanobranches constructed by ultrathin nanosheets with high-energy {110} facets and high surface area was successfully synthesized, which shows a high selectivity of complete oxidation ethanol to CO2up to 15.8% (at 0.0 V vs Hg/HgO) in alkaline solution, outperforming currently reported monometallic electro-catalysts. The in situFourier transform infrared reflection spectroscopy and density function theory calculations demonstrated that the CC bond cleavage of ethanol is very sensitive to the structure of Rh crystallites, and the unique {110} facets and excavated polyhedral morphology endow the Rh electro-catalysts with unexpected high selectivity, as well as high electro-catalytic activity and great structural stability.

Although the negative effects of CeO2nanoparticles (nano-CeO2) on wastewater biological nitrogen removal (BNR) systems have been documented, the potential and mechanisms of the stress tolerance and resilience of nitrifiers to nano-CeO2exposure remain unclear. Herein, we explored the long-term impacts of nano-CeO2on a continuously cultured model ammonia oxidizer, Nitrosomonas europaea, and assessed the recovery capacities of nano-CeO2stressed cells at the physiological and transcriptional levels. Nano-CeO2at 50 mg L−1remarkably inhibited the bacterial growth, the membrane integrity, the ammonium removal performance and the specific ammonia monooxygenase activity. Meanwhile, N. europaeaexhibited a tolerance capacity to the nano-CeO2stress and their metabolic activities were maintained even after 40 d nano-CeO2exposure. The batch recovery incubation study revealed the inhibition level-dependent recovery potential of nano-CeO2impaired N. europaeacultures. Transcriptomics-based investigation indicated that nano-CeO2induced the disruptions of the membrane structure and the associated transport systems. Nevertheless, the peptidoglycan biosynthesis and ATP-binding cassette transport relevant metabolism regulation probably played a pivotal role in cellular stress tolerance/recovery. In particular, the transcriptional regulation of energy metabolism pathways, such as CO2fixation, respiratory chain and ATP production, might favor the bacterial protection/recovery from the nano-CeO2stress. Moreover, diverse metabolic regulation at the transcriptional levels, including DNA repair, oxidative stress quenching, and signal transduction would be actively involved in cellular protection against nano-CeO2and impaired cells' metabolic activity recovery. These findings improved our understanding of stress responses and resilience of nitrifiers to NPs and provided novel insights into adjustment strategy determination for the potential NP impacts on BNR systems.

Developing active and durable electro-catalysts toward ethanol oxidation reaction (EOR) with high selectivity toward the C–C bond cleavage is an important issue for the commercialization of direct ethanol fuel cell. Unfortunately, current ethanol oxidation electro-catalysts (e.g., Pt, Pd) still suffer from poor selectivity for direct oxidation of ethanol to CO2, and rapid activity degradation. Here we report a facile route to the synthesis of a new kind of cyclic penta-twinned (CPT) Rh nanostructures that are self-supported nanobranches (NBs) built with 1-dimension CPT nanorods as subunits. Structurally, the as-prepared Rh NBs possess high percentage of open {100} facets with significant CPT-induced lattice strains. With these unique structural characteristics, the as-prepared CPT Rh NBs exhibit outstanding electrocatalytic performance toward EOR in alkaline solution. Most strikingly, the selectivity of complete conversion ethanol to CO2on the CPT Rh NBs is measured to be as high as 14.5 ± 1.1% at −0.15 V, far exceeding that for single-crystal tetrahedral nanocrystals, icosahedral nanocrystals, and commercial Rh black, as well as majority of reported values for Pt or Pd-based electro-catalysts. By combining with density functional theory calculation, the effects of different structural features of Rh on EOR are definitively elucidated. It was found that the large amount of open Rh (100) facets dominantly contribute to the outstanding activity and exceptionally high selectivity, while the additional tensile strain on (100) planes can further boost the catalytic activity by enhancing the adsorption strength and lowering the reaction barrier of dehydrogenation process of ethanol. As a proof of concept, the present work shows that rationally optimizing surface and electronic structure of electro-catalysts by simultaneously engineering their surface and bulk structures is a promising strategy to promote the performance of electro-catalysts.

Direct formic acid fuel cells (DFAFCs) are a promising clean power source. To date, palladium (Pd)-based catalysts are the best promising anode catalyst for DFAFCs due to its high anti-poisoning ability and low cost. In this paper, we report a high-efficiency stable PdHxnanocatalyst towards DFAFCs. The PdHxnanocatalysts are prepared by simply treating the commercial Pd black with n-butylamine at relative low temperature (100–200°C). They are extremely stable, and the as-prepared PdH0.43nanocatalysts show extremely low overpotential for formic acid electrooxidation, with an oxidation peak potential of 0.04V versus SCE (saturated calomel electrode). Meanwhile, the PdH0.43exhibits as high as 3 times mass activity, 5 times specific activity and great catalytic stability, compared with the untreated commercial Pd black. The present strategy offers a convenient way to boost the performance of Pd nanocatalysts in DFAFCs.

Selective breaking of the C-C bond in ethanol holds the key to many industrial processes, including the operation of direct ethanol fuel cells and steam reforming. Interstitial C atoms in the subsurface region of noble-metal catalysts have major impacts on the selectivity and activity, but an understanding of the mechanistic details is still elusive due to their nature of in situ formation and metastability. Herein, we develop a method to obtain stable RhCx(x ≈ 0.5) by introducing C atoms into the interstitial sites of well-defined Rh nanosheets of 8–10 at. layers in thickness, and further elucidate the electronic and geometric effects of the interstitial C atoms on the cleavage of C-C bond. With the introduction of C atoms into half of the octahedral sites, the Rh lattice changes from a cubic to an orthorhombic structure. The lattice expansion induced by the insertion of C atoms, together with the electron transfer between C and Rh atoms, effectively suppresses the coupling reaction between OH* and CH3CO* to form acetic acid while making the cleavage of C-C bond more exothermic. As such, we obtain a selectivity of ethanol to CO2as high as 18.1 %, much higher than those of the Rh counterpart (10.0 %), together with 3.1-fold improvement in kinetics. Guided by these findings, a new method is also developed to directly introduce C atoms into the subsurface of a commercial Rh black to enhance its selectivity and activity by 2.5- and 1.6- folds, respectively.

The electroreduction of carbon dioxide into high-value-added products is an effective approach to alleviating the energy crisis and pollution issues. However, there are still significant challenges for multicarbon (C2+) product production due to the lack of efficient catalysts with high selectivity. Herein, a Cu-rich electrocatalyst, where Cu2O nanoparticles are decorated on two-dimensional (2D) Cu-BDC metal–organic frameworks (MOFs) with abundant heterogeneous interfaces, is synthesized for highly selective CO2electroreduction into C2+products. A high C2+Faradaic efficiency of 72.1% in an H-type cell and 58.2% in a flow cell are obtained, respectively. The heterogeneous interfaces of Cu2O/Cu-BDC can optimize the adsorption energy of reaction intermediates during CO2electroreduction. An in situ infrared spectroscopy study indicates that the constructed interfaces can maintain the particular distribution of Cu valence states, where the C–C coupling is promoted to efficiently produce C2+products owing to the stabilization of *CHO and *COH intermediates.

Designing efficient formic acid oxidation reaction (FAOR) catalysts with remarkable membrane electrode assembly (MEA) performance in a direct formic acid fuel cell (DFAFC) medium is significant yet challenging. Herein, we report that the monoclinic-phased platinum–tellurium nanotrepang (m-PtTe NT) can be adopted as a highly active, selective, and stable FAOR catalyst with a desirable direct reaction pathway. The m-PtTe NT exhibits the high specific and mass activities of 6.78 mA cm–2and 3.2 A mgPt–1, respectively, which are 35.7/22.9, 2.8/2.6, and 3.9/2.9 times higher than those of commercial Pt/C, rhombohedral-phased Pt2Te3NT (r-Pt2Te3NT), and trigonal-phased PtTe2NT (t-PtTe2NT), respectively. Simultaneously, the highest reaction tendency for the direct FAOR pathway and the best tolerance to poisonous CO intermediate can also be realized by m-PtTe NT. More importantly, even in a single-cell medium, the m-PtTe NT can display a much higher MEA power density (171.4 mW cm–2) and stability (53.2% voltage loss after 5660 s) than those of commercial Pt/C, demonstrating the great potential in operating DFAFC device. The in-situFourier transform infrared spectroscopy and X-ray photoelectron spectroscopy jointly demonstrate that the unique nanostructure of m-PtTe NT can effectively optimize dehydrogenation steps and inhibit the CO intermediate adsorption, as well as promote the oxidation of noxious CO intermediate, thus achieving the great improvement of FAOR activity, poisoning tolerance, and stability. Density functional theory calculations further reveal that the direct pathway is the most favorable on m-PtTe NT than r-Pt2Te3NT and t-PtTe2NT. The higher activation energy to produce CO and the relatively weaker binding with CO of m-PtTe NT result in the better CO tolerance. This work achieves remarkable FAOR and MEA performances of advanced Pt-based anodic catalysts for DFAFCs via a phase engineering strategy.

Optimizing the interatomic distance of dual sites to realize C–C bond breaking of ethanol is critical for the commercialization of direct ethanol fuel cells. Herein, the concept of holding long-range dual sites is proposed to weaken the reaction barrier of C–C cleavage during the ethanol oxidation reaction (EOR). The obtained long-range Rh–O–Pt dual sites achieve a high current density of 7.43 mA/cm2toward EOR, which is 13.3 times that of Pt/C, as well as remarkable stability. Electrochemical in situFourier transform infrared spectroscopy indicates that long-range Rh–O–Pt dual sites can increase the selectivity of C1 products and suppress the generation of a CO intermediate. Theoretical calculations further disclose that redistribution of the surface-localized electron around Rh–O–Pt can promote direct oxidation of −OH, accelerating C–C bond cleavage. This work provides a promising strategy for designing oxygen-bridged long-range dual sites to tune the activity and selectivity of complicated catalytic reactions.

Tuning the electronic structure of heterogeneous metal catalysts has emerged as an effective strategy to optimize their catalytic activities. By preparing ethylenediamine-coated ultrathin platinum nanowires as a model catalyst, here we demonstrate an interfacial electronic effect induced by simple organic modifications to control the selectivity of metal nanocatalysts during catalytic hydrogenation. This we apply to produce thermodynamically unfavourable but industrially important compounds, with ultrathin platinum nanowires exhibiting an unexpectedly high selectivity for the production of N-hydroxylanilines, through the partial hydrogenation of nitroaromatics. Mechanistic studies reveal that the electron donation from ethylenediamine makes the surface of platinum nanowires highly electron rich. During catalysis, such an interfacial electronic effect makes the catalytic surface favour the adsorption of electron-deficient reactants over electron-rich substrates (that is, N-hydroxylanilines), thus preventing full hydrogenation. More importantly, this interfacial electronic effect, achieved through simple organic modifications, may now be used for the optimization of commercial platinum catalysts.

Intelligent display with multifunctional integration is becoming the frontier and focus of current research on novel display technology. How to realize the single chip integration of lighting with other functions such as switching and driving remain the technical and scientific problems that are desiderated to solve. This article proposes a novel idea of a light‐emitting triode (LET), in which light‐emitting diode (LED) and bipolar junction transistor (BJT) are vertically integrated on a single GaN chip with the same GaN processing. The photoelectrical performances of this “LED on BJT” structure are investigated using finite element simulation. It is verified that LET with electrical–optical modulation and amplification capabilities could be achieved simultaneously. By optimizing the device structure and the doping concentrations of each epitaxial layers, the LET can be operated at a low modulation current injection in the range of tens of microamperes. Therefore, the LET is expected to be directly driven by IC circuits without additional amplifier circuits. Meanwhile, the LET cut‐off frequency can reach more than 80 MHz, allowing the applications of pulse width modulation (PWM) driving and visible light communications. Herein, a GaN‐based triode (LET) vertically integrated device is proposed. The performance of the device is studied by finite element simulation. The results show that the device has obvious electro‐optic modulation characteristics and can emit light under low current injection, and its cut‐off frequency can reach more than 80 MHz.

This study aims to understand the effects of functional agents such as capping agents, stabilizers, surfactants and additives in shape-controlled synthesis of nanomaterials. The well-defined Pt(100) single crystal surface was used as a model to investigate its interaction with citrate, a capping agent that is often used in shape-controlled synthesis of nanomaterials. It demonstrated that, through a systematic study of electrochemical cyclic voltammetry, the presence of citrate in solution could increase the current peak density of hydrogen adsorption at high potential (jp,L), while decrease proportionally the current peak density of hydrogen adsorption at low potential (jp,S). Furthermore, the increase of citrate concentration shifted negatively the peak potentials (Ep,Land Ep,S) of both jp,Land jp,S. The results indicated that the interaction of citrate with Pt(100) surface could induce increasing the (100) surface domains of two-dimensional long range order (2D-(100)), and decreasing the (100) surface domains of one-dimensional short range order (1D-(100)). It also revealed that the interaction of citrate with Pt(100) surface could stabilize the 2D-(100) structure. The findings gained in this study implied that the citrate may lead to form stable 2D-(100) domains on Pt nanoparticles upon the shape-controlled synthesis of Pt nanomaterials.This study aims to understand the effects of functional agents such as capping agents, stabilizers, surfactants and additives in shape-controlled synthesis of nanomaterials. The well-defined Pt(100) single crystal surface was used as a model to investigate its interaction with citrate, a capping agent that is often used in shape-controlled synthesis of nanomaterials. It demonstrated that, through a systematic study of electrochemical cyclic voltammetry, the presence of citrate in solution could increase the current peak density of hydrogen adsorption at high potential (jp,L), while decrease proportionally the current peak density of hydrogen adsorption at low potential (jp,S). Furthermore, the increase of citrate concentration shifted negatively the peak potentials (Ep,Land Ep,S) of both jp,Land jp,S. The results indicated that the interaction of citrate with Pt(100) surface could induce increasing the (100) surface domains of two-dimensional long range order (2D-(100)), and decreasing the (100) surface domains of one-dimensional short range order (1D-(100)). It also revealed that the interaction of citrate with Pt(100) surface could stabilize the 2D-(100) structure. The findings gained in this study implied that the citrate may lead to form stable 2D-(100) domains on Pt nanoparticles upon the shape-controlled synthesis of Pt nanomaterials.

CO poisoning of Pt-group metal catalysts is a long-standing problem, particularly for hydrogen oxidation reaction in proton exchange membrane fuel cells. Here, we report a catalyst of Ru oxide-coated Ru supported on TiO2(Ru@RuO2/TiO2), which can tolerate 1–3% CO, enhanced by about 2 orders of magnitude over the classic PtRu/C catalyst, for hydrogen electrooxidation in a rotating disk electrode test. This catalyst can work stably in 1% CO/H2for 50 h. About 20% of active sites can survive even in a pure CO environment. The high CO tolerance is not via a traditional bifunctional mechanism, i.e., oxide promoting CO oxidation, but rather via hydrous metal oxide shell blocking CO adsorption. An ab initio molecular dynamics (AIMD) simulation indicates that water confined in grain boundaries of the Ru oxide layer and Ru surface can suppress the diffusion and adsorption of CO. This oxide blocking layer approach opens a promising avenue for the design of high CO-tolerant electrocatalysts for fuel cells.

Inferior stability and anti-poisoning capacity of Pt-based ultrathin nanowires (NWs) are critical weaknesses under detrimental acidic running conditions for proton-exchange membrane fuel cell applications due to their energetic surface. Here 1.5-nm-thin quatermetallic PtCoNiRh NWs with high atomic-exposure are fabricated to serve as robust electrocatalysts for acidic methanol oxidation reaction (MOR). Surpassing Rh-free PtCoNi NWs and most of state-of-the-art catalysts, the PtCoNiRh NWs achieve extremely high MOR activity (1.36 A·mg−1Ptand 2.08 mA cm−2) with substantially lowered onset-potential and improved CO-tolerance. The anticorrosion effect of incorporated-Rh can effectively stabilize the PtCoNiRh NWs in the corrosive MOR. Electrochemical in situ Fourier transform infrared spectroscopy and density functional theory simulation cooperatively reveal that the methanol dehydrogenation is inclined to occur at the interatomic Pt–Rh sites, where the intermediate COadsprefers bridge binding mode rather than linear mode with facilitated removal. Integratedly, the complete 6e−-transferred MOR process is reliably accelerated and stays efficient on the quaternary PtCoNiRh NWs.