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Au nanoparticles sensitized ZnO nanorod@nanoplatelet (NR@NP) core–shell arrays have been synthesized via a facile hydrothermal method followed by a further modification using Au nanoparticles. The resulting Au–ZnO NR@NP nanoarray exhibits promising behavior in photoelectrochemical (PEC) water splitting, giving rise to a largely enhanced photocurrent density, photoconversion efficiency as well as incident-photon-to-current-conversion efficiency (IPCE), much superior to those of pristine ZnO nanorods arrays and ZnO NR@NP. This is attributed to the coordination of ZnO core–shell hierarchical nanostructure and the surface-plasmon-resonance effect of Au nanoparticles, which facilitates the exposure of active sites and utilization of visible light. Density functional theory (DFT) calculations further confirm that the photogenerated electrons of ZnO transfer to Au, which suppresses the recombination of electron–hole pairs. Therefore, this work provides a facile and cost-effective strategy for the construction of hierarchical metal/semiconductor nanoarrays, which can be potentially used in the field of energy storage and conversion. [ABSTRACT FROM AUTHOR]

Well-aligned hierarchical nanoarrays containing ZnO core and layered double hydroxide (LDH) nanoplatelets shell have been synthesized via a facile electrosynthesis method. The resulting ZnO@CoNi-LDH core−shell nanoarray exhibits promising behavior in photoelectrochemical water splitting, giving rise to a largely enhanced photocurrent density as well as stability; much superior to those of ZnO-based photoelectrodes. This is attributed to the successful integration of photogenerated electron-hole separation originating from the ZnO core and the excellent electrocatalytic activity of LDH shell. This work provides a facile and cost-effective strategy for the fabrication of multifunctional nanoarrays with a hierarchical structure, which can be potentially used in energy storage and conversion devices. [ABSTRACT FROM AUTHOR]

The effective depress dendrite growth of metal anodes (such as lithium (Li), sodium (Na), potassium (K) and zinc (Zn)) have been widely considered for metal-based batteries. However, regarding varied metal batteries accompanied with different chemical environment (e.g, solvent effect, electronegativity and ion radius), it is a huge challenge to develop a general approach for construction of dendrite-free metal anodes. Herein, we report a strategy to induce Li, Na, K and Zn homogenous nucleation by 'F' heteroatom doped TiO 2 nanorod arrays. Theoretical calculations reveal that Li+, Zn2+, Na+ and K+ can be strong adhered to electronegative F heteroatom, giving rise to an enhanced nucleophilicity. Consequently, the CC/TiO 2 -F based Li, Zn, Na and K symmetric cells exhibit remarkably enhanced long service life of 1100 h, 530 h, 720 h and 510 h at 2 mA cm–2 with a low voltage hysteresis, which is 4.4, 26.5, 24.1 and 25.5 times higher than that of bare CC based anodes. Moreover, the CC/TiO 2 -F dendrite-free anode allows for construction of Li-LiFePO 4 /Sulfur full-batteries with a high capacity of 152 mA h g–1 and 1070 mA h g–1, respectively. Additionally, the assembled Li–S pouch cells also realized high stable capacity with high flexibility. This work provides an important strategy to develop general method for dendrite-free metal anodes towards high-performance metal batteries. Homogenous nucleation and deposition of various metals (Li, Na, K and Zn) has been realized by F doped TiO 2 nanorod arrays, which is originated from greatly enhancement of nucleophilicity by strong Lewis-acid based F-sites. As a result, the CC/TiO 2 -F displays promising applications as Li, Na, K and Zn metallic anodes for high-performance metal batteries. [Display omitted] • Free-standing 3D TiO 2 -F arrays on carbon cloth (CC/TiO 2 -F) were prepared via hydrothermal and electrochemical activation process. • The F heteroatom serving as electronegativity center decreases all nucleation barrier of Li, Na, K and Zn, resulting homogenous nucleation. • All of CC/TiO 2 -F based Li, Na, K and Zn symmetric cells exhibit long cycling life. • The full metal batteries assembled by CC/TiO 2 -F@Li and LiFePO 4 (LFP)/sulfur (S) provide a high capacity and long cycling life. [ABSTRACT FROM AUTHOR]

Core–shell layered double hydroxide microsphereswith tunable interior architecturehave been synthesized by a facile and cost-effective in situgrowth method. The SEM and TEM images revealed that the obtainedmicrospheres display a three-dimensional architecture with core–shell,yolk–shell, and hollow interior structure respectively, withcontinuous changes in specific surface area and pore-size distribution.Moreover, the hollow NiAl-LDH microspheres exhibit excellent pseudocapacitanceperformance, including high specific capacitance and rate capability,good charge/discharge stability and long-term cycling life, owingto the greatly improved faradaic redox reaction and mass transfer.Therefore, this work provides a promising approach for the designand synthesis of structure tunable materials with largely enhancedsupercapacitor behavior, which can be potentially applied in energystorage/conversion devices. [ABSTRACT FROM AUTHOR]

Abstract: The ordered ultrathin film based on iron(III) porphyrin and Co–Al layered double hydroxide (Co–Al LDH) nanosheets has been fabricated via the layer-by-layer (LBL) method. The film modified electrode demonstrates a couple of well-defined reversible redox peaks attributed to Co(III)/Co(II), with iron(III) porphyrin serving as an efficient mediator for facilitating the electron transfer. Furthermore, it exhibits excellent electrocatalytic behavior for H2O2 with a wide linear range of response, high sensitivity and low detection limit. [Copyright &y& Elsevier]

Electrocatalytic oxidation of glycerol, an oversupplied byproduct of the biodiesel industry, into high‐valued chemicals is alluring to diminishing current dependence on fossil energy. Formic acid is an important glycerol oxidation product that serves as a high‐energy‐density fuel and crucial precursor for the fine chemical industry while developing an electrocatalyst to efficiently convert glycerol into formic acid remains a challenge. Herein, a Cu‐doped nickel phosphide (CuxNi2–xP) electrocatalyst, achieving formate productivity of ≈11 mol m−2 h−1 at 1.54 V versus RHE over a broad glycerol concentration range (10–100 mm) is reported, which is greater than threefolds than that of Ni2P. Furthermore, CuxNi2–xP can enhance the cleavage of C─C bond in glycerol, reducing the production of intermediates and thus attaining high selectivity of formate. In situ experiments integrated with density functional theory (DFT) calculation revealed that the doping of Cu can promote the generation of NiIII─OOH species and enrich glycerol substrates in local environments on CuxNi2–xP surface, thus facilitating reaction efficiency. Finally, the study designed a membrane‐free flow electrolyzer for continuous upgrading glycerol to formate, attaining 16.4 mmol of formate coupled with 0.68 L of H2 at 1.75 V in 8 h. [ABSTRACT FROM AUTHOR]

The efficient transformation of chemicals and electricity via electrocatalytic hydrogen evolution reaction (HER) plays a pivotal role in green hydrogen production. Both in academia and industry, the pursuit of designing and fabricating catalysts for HER that are not only efficient and robust but also environmentally friendly is of significant interest. In this work, a ruthenium catalyst doped with nickel was synthesized using a procedure-minimal and solvent-free method facilitated by microwave-assisted pyrolysis. The incorporation of alloying and optimized electronic structures has resulted in Ru-based nanocrystals that change the HER mechanism and enable enhanced activity. The optimal RuNi/C catalyst demonstrates an overpotential of only 15 mV at a current density of 10 mA cm−2, with a Tafel slope of 24 mV dec−1, surpassing the performance of the state-of-the-art Pt/C catalyst. Remarkably, the prepared catalyst exhibits admirable corrosion resistance, making it a highly promising candidate for green hydrogen production through seawater splitting. A ruthenium catalyst doped with nickel is synthesized through a solvent-free microwave treatment, and exhibits a Pt-surpassed activity towards HER. [Display omitted] • A ruthenium catalyst doped with nickel is synthesized via a green method. • The HER mechanism on ruthenium is transferred by the doped nickel. • The optimized catalyst shows a platinum-surpassed activity for HER. • Superior corrosion resistance and durability is achieved for seawater splitting. [ABSTRACT FROM AUTHOR]

Highlights: Hierarchical carbon microtube@nanotube (CMT@CNT) core–shell nanostructure is successfully synthesized. The CMT@CNT shows superior electrocatalytic activity for oxygen reduction reaction and oxygen evolution reaction. A mass-loading independent high performance for zinc–air battery is achieved on the CMT@CNT. Zinc–air batteries (ZABs) hold tremendous promise for clean and efficient energy storage with the merits of high theoretical energy density and environmental friendliness. However, the performance of practical ZABs is still unsatisfactory because of the inevitably decreased activity of electrocatalysts when assembly into a thick electrode with high mass loading. Herein, we report a hierarchical electrocatalyst based on carbon microtube@nanotube core–shell nanostructure (CMT@CNT), which demonstrates superior electrocatalytic activity for oxygen reduction reaction and oxygen evolution reaction with a small potential gap of 0.678 V. Remarkably, when being employed as air–cathode in ZAB, the CMT@CNT presents an excellent performance with a high power density (160.6 mW cm−2), specific capacity (781.7 mAhgZn−1) as well as long cycle stability (117 h, 351 cycles). Moreover, the ZAB performance of CMT@CNT is maintained well even under high mass loading (3 mg cm−2, three times as much as traditional usage), which could afford high power density and energy density for advanced electronic equipment. We believe that this work is promising for the rational design of hierarchical structured electrocatalysts for advanced metal-air batteries. [ABSTRACT FROM AUTHOR]

Electrocatalytic technology provides a promising approach for energy storage, conversion, and utilization. The design and modification of electrocatalysts have been widely applied to improve the performance of electrocatalytic reactions, but bottlenecks can be entered that make it hard to make dramatic progress. The achievement of high‐performance electrocatalysis requires a continuous effort in advancing the new techniques. The introduction of external fields is an attractive approach to improve the mass transfer and change the reaction kinetics, which can remarkably enhance the electrocatalytic performance. This review describes the recent developments in the application of various external fields, including light, magnetic fields, elastic strain, external pressure, and gravity, to boost electrocatalytic reactions (e.g., water splitting, alcohols oxidation, CO2 reduction, and N2 reduction). The relevant mechanisms of external fields to boost charge transport, mass transfer, and the adsorption of reactants are highlighted. Finally, the remaining challenges and future opportunities for coupling external fields with electrocatalysis are discussed. [ABSTRACT FROM AUTHOR]

Regarding the complex properties of various cations, the design of aqueous batteries that can simultaneously store multi‐ions with high capacity and satisfactory rate performance is a great challenge. Here an amorphization strategy to boost cation‐ion storage capacities of anode materials is reported. In monovalent (H+, Li+, K+), divalent (Mg2+, Ca2+, Zn2+) and even trivalent (Al3+) aqueous electrolytes, the capacity of the resulting amorphous MoOx is more than quadruple than that of crystalline MoOx and exceeds those of other reported multiple‐ion storage materials. Both experimental and theoretical calculations reveal the generation of ample active sites and isotropic ions in the amorphous phase, which accelerates cation migration within the electrode bulk. Amorphous MoOx can be coupled with multi‐ion storage cathodes to realize electrochemical energy storage devices with different carriers, promising high energy and power densities. The power density exceeded 15000 W kg−1, demonstrating the great potential of amorphous MoOx in advanced aqueous batteries. [ABSTRACT FROM AUTHOR]

Transition‐metal‐based oxyhydroxides are efficient catalysts in biomass electrooxidation towards fossil‐fuel‐free production of valuable chemicals. However, identification of active sites remains elusive. Herein, using cobalt oxyhydroxide (CoOOH) as the archetype and the electrocatalyzed glucose oxidation reaction (GOR) as the model reaction, we track dynamic transformation of the electronic and atomic structure of the catalyst using a suite of operando and ex situ techniques. We reveal that two types of reducible Co3+‐oxo species are afforded for the GOR, including adsorbed hydroxyl on Co3+ ion (μ1‐OH−Co3+) and di‐Co3+‐bridged lattice oxygen (μ2‐O−Co3+). Moreover, theoretical calculations unveil that μ1‐OH−Co3+ is responsible for oxygenation, while μ2‐O−Co3+ mainly contributes to dehydrogenation, both as key oxidative steps in glucose‐to‐formate transformation. This work provides a framework for mechanistic understanding of the complex near‐surface chemistry of metal oxyhydroxides in biomass electrorefining. [ABSTRACT FROM AUTHOR]

Highly effective and efficient recover of silver ions from aqueous media remains a serious task for public health and ecosystem protection. Herein, we report that this task can be addressed by in situ reduction of Ag+ to metallic silver (Ag0) with manganese–aluminum layered double hydroxide (MnAl–NO3–LDH) as framework, which can be synthesized with a facile, green, and scalable approach. As a result, the MnAl–NO3–LDH presents excellent rapid uptake of Ag+ with high uptake capacity (less than 2 min, 832.9 mg/g), outperforming most state-of-the-art adsorbents. Furthermore, the MnAl–NO3–LDH achieved excellent separation selectivity for Ag+ from Cu2+ at a high mass ratio of Cu2+/Ag+ (500:1). These superior properties coupled with low cost and environmentally benign nature make MnAl–NO3–LDH a promising candidate for recovery of Ag+ as well as other potential applications. [ABSTRACT FROM AUTHOR]

Room temperature liquid NaK alloy is a promising candidate for high performance metal batteries, due to its dendrite-free property and high energy density. However, its practical application is hindered by the high surface tension of liquid NaK, which causes difficulties in maintaining a stable contact with a current collector. Here, the authors demonstrate the extraordinary stable confinement of NaK alloy at room temperature by constructing a super-wetting substrate, which is based on highly dispersed cobalt-single-atom carbon nanoarrays. The developed liquid anode electrode prevented successfully the leakage of NaK alloy even in harsh stress (>5 MPa) or sharp shock conditions. The symmetric cells achieved ultra-long reversible plating/stripping cycling life in both Na-ion (>1010 hrs) and K-ion electrolytes (>4000 hrs) at 10 mAcm-2/10 mAh cm-2. Upon fitting with Na3V2(PO4)3, the NaK assembled full battery provided high energy density (332.6 kWh kg-1) and power density (11.05 kW kg-1 ) with excellent stability after >21600 cycles, which is the best value reported so far. The prepared pouch cell was able to drive a four-axis aircraft, demonstrating a great prospect in practical application. This work offers a new approach in the preparation of advanced dendrite-free liquid metal anodes with promising applications in electrochemical energy storage. [ABSTRACT FROM AUTHOR]

• EHCO has enhanced the cost-efficiency water electrolysis systems. • Summarize and compare the progress of traditional water electrolysis and EHCO. • Utilize TEA to evaluate the economic viability of water electrolysis. • Discuss the challenges and opportunities of water electrolysis. Water electrolysis, a sustainable and eco-friendly alternative to fossil-fuel-based hydrogen production, is gaining prominence for its high-purity hydrogen output. However, the current practical application of hydrogen production from water electrolysis is hampered by low efficiency and high costs. Recent advances in high-efficiency cathodic and anodic electrocatalysts have markedly enhanced hydrogen production efficiency. Furthermore, electrochemical hydrogen evolution coupled with alternative oxidation, offers a pathway to reduce energy consumption and costs. For the widespread industrial adoption of water electrolysis, it is imperative to not only develop high-efficiency electrocatalysts and coupling systems but also to integrate techno-economic analysis into the process. In this review, we present a detailed techno-economic analysis of existing water electrolysis systems, evaluating their industrial viability. Our analysis delves into aspects such as energy consumption, chemical and equipment costs, and more. We specifically scrutinize the feasibility of hydrogen production from water electrolysis and the potential of electrochemical hydrogen evolution, particularly when coupled with alternative oxidation processes like alcohol or aldehyde oxidation reactions. Concluding with a forward-looking perspective, we discuss future directions in hydrogen production technology, focusing on advancements in electrocatalyst synthesis, selection of coupling reactions, and optimization of equipment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metal oxide catalysts with tunable acid-base sites were prepared based on layered double hydroxides (LDHs) precursor. • Co 1 Al 2 -MMO-200 sample exhibits good catalytic performance toward catalytic transfer hydrogenation (CTH) reaction. • The CTH reaction of FAL occurs through the Meerwein-Ponndorf-Verley (MPV) pathway over the Co 1 Al 2 -MMO-200 catalyst. • The synergistic effect of acid-base sites plays a vital role in determining the catalytic behavior. Catalytic transfer hydrogenation (CTH) of aldehydes/ketones by using alcohols as hydrogen donors is an attractive and environmentally friendly hydrogenation technology, which has evoked widespread attention in synthesis of fine chemicals from biomass resources. In this work, a Co-Al mixed metal oxide catalyst (Co 1 Al 2 -MMO-200) was obtained through structural topological transformation process of layered double hydroxides, which was used in the CTH reaction of furfural with isopropanol. Notably, the reaction rate achieves 0.023 mol g−1 h−1, which is preponderate to acid-base catalysts earlier reported. The joint research based on CO 2 -TPD, NH 3 -TPD and poisoning experiment substantiates that the synergy effect of acid-base sites plays an essential role in this catalytic system. Isotopic labelling MS, in-situ FT-IR and DFT studies further verify that the CTH reaction of furfural occurs via the Meerwein-Ponndorf-Verley (MPV) route, in which the basic site promotes the deprotonation of isopropanol whilst the acid site facilitates the formation of a six-membered ring transition state. This work demonstrates an acid-base synergetic catalysis for the CTH reaction by revealing the structure-property correlation and exploring reaction route, which is instructive for designing high-performance heterogenous catalysts. [ABSTRACT FROM AUTHOR]

Photocatalytic CO 2 reduction has drawn widespread attention across all sectors of society. Layered double hydroxides (LDHs) have emerged as promising photocatalysts, renowned for their adjustable bandgaps and reaction sites. As a typical anionic layered material, LDHs exhibit intricate interactions between interlayer anions and brucite-like metal layers, greatly influencing their inherent physicochemical properties. In this work, we synthesized ZnAl-LDH samples intercalated with four distinct anions: carbonate (CO 3 2–), chloridion (Cl–), nitrate (NO 3 –), and dodecyl sulfate (DS–), denoted as LDH-CO 3 , LDH-Cl, LDH-NO 3 , and LDH-DS, respectively. These LDHs samples have comparable crystallinity and morphology but differ in their interlayer spacing. XRD results reveal interlayer spacings of 0.77 nm for LDH-CO 3 , 0.78 nm for LDH-Cl, 0.88 nm for LDH-NO 3 , and 1.24 nm for LDH-DS, between adjacent brucite-like ZnAl hydroxide layers. Remarkably, LDH-NO 3 demonstrates the highest photocatalytic CO 2 reduction performance, with CO as the primary reduction product. Specifically, the average CO production rate of LDH-NO 3 are 3.80 μmol g–1 h–1, surpassing that of LDH-CO 3 , LDH-Cl, and LDH-DS by 1.9, 2.1, and 2.5 times, respectively. This superior performance can be attributed to the intermediate interlayer spacing of LDH-NO 3 , which facilitates strong light absorption and a robust local built-in electric field. Theses properties enhance charge generation and separation abilities, leading to efficient photocatalytic reactions. The obtained results highlight the critical role of controlling small molecules within the interlayer, alongside defects, in the design and fabrication of layered-structure photocatalysts. This study provides valuable insights into optimizing the performance of LDH-based photocatalysts for CO 2 reduction and potentially other photocatalytic applications. [Display omitted] • Four ZnAl-LDH samples with varying anion intercalation were prepared. • ZnAl-LDHs with CO 3 2–, Cl–, NO 3 –, and DS– anions intercalated exhibited increased interlayer spacing. • Among these ZnAl-LDH samples, LDH-NO 3 displayed the highest photocatalytic performance. • The intermediate interlayer spacing of LDH-NO 3 possesses strong local charge separation driving force. [ABSTRACT FROM AUTHOR]

• A facile one-pot method for synthesizing 3D honeycomb-like LDHs/chitosan beads. • The oriented aggregation and growth of the LDHs induced the unique structure. • The MgFe-LDH/chitosan beads exhibited well removal performance to Pb2+ in spirit. Presence of toxic lead (Pb2+) in alcoholic beverages in trace concentrations has been documented in literature. However, only a handful of facile and inexpensive treatments can effectively remove Pb2+ from alcoholic beverages. Herein, a convenient approach for the synthesis of hydride beads is presented that is composed of chitosan and layered double hydroxides (LDHs), in which the LDH nanosheets were grown on the chitosan skeletons and resulted in a hierarchical structure with interconnected network of LDH nanosheets. In particular, the as-synthesized MgFe-LDH/chitosan beads were used as a model to evaluate their capacity to remove trace Pb2+ from spirit. The as-synthesized MgFe-LDH/chitosan beads exhibited good stability, and excellent removal capacity for Pb2+ that could decrease the concentration of Pb2+ from 2 to 0.005 mg/L, which is well below the acceptable limits in alcoholic beverages in China (0.5 mg/L). The results from X-ray photoelectron spectroscopy (XPS) and structural characterizations confirmed the presence of strong interactions between Mg sites and Pb2+. Furthermore, the experiments with laboratory-scale column system demonstrated the potential feasibility of the proposed method in practical applications. It is envisioned that the work can provide a convenient, efficient, safe and cost-effective strategy to address the issue of treating alcoholic beverages contaminated by heavy metals. Additionally, a series of LDH-based beads were also synthesized using the proposed method, offering a platform to address the challenges faced when LDHs are used in powdered forms. [ABSTRACT FROM AUTHOR]

• Hierarchical CNT hollow microspheres with tunable size are successfully synthesized. • CNT HMS show superior electrochemical activity for ORR than solid carbon particles. • Optimized CNT HMS deliver a mass-loading independent high performance for ZAB. • CNT HMS endow the highly efficient utilization of active materials. Although carbon materials have shown large potential as efficient electrocatalysts for oxygen reduction reaction (ORR), their practical performance with high energy density and power density is difficult to maintain under high mass-loading due to the compact restacking that seriously hinders mass/charge diffusion. To overcome this issue, we demonstrate the design and synthesis of hierarchical Co-N-codoped carbon nanotube hollow microspheres (CNT HMSs) with high disperse, large surface area and uniform mesopores, which effectively guarantees the high electrochemical activity and stability towards ORR even under high mass-loading. As a result, the power density of Zn-air battery based on CNT HMS gradually enhances from 52.8 to 183.8 mW cm−2 with a good linear relationship when the mass-loading increases from 1.5 (traditional used for most reported works) to 6.0 mg cm−2, indicating a well-preserved catalytic activity with high mass-loading. In addition, the long-term stability (10 h) test illustrates that monodisperse morphology and uniform size distribution of CNT HMS have been well maintained, while the referent carbon particles show serious agglomeration and obvious increased particle size. This suggests a much enhanced stability of CNT HMS compared with traditional particles, which offers large opportunity for the practical applications in metal-air batteries or fuel cells. [ABSTRACT FROM AUTHOR]

Graphical abstract The (Ni, Fe)S 2 @MoS 2 heterostructures are directly prepared, which exhibits remarkable electrochemical performance towards overall water splitting. The interface engineering of obtained sulfides facilitie formation of S-H ads , which synergistically lower the chemisorption energy of the intermediates of HER and OER, thereby facilitating the electrocatalytic overall water splitting. Highlights • A synergetic electrocatalyst is achieved for water splitting based on (Ni, Fe)S 2 @MoS 2 heterostructrues. • The interface engineering of sulfide heterostructures facilitates the formation of S-H ads. • The stability can be further enhanced by optimizing the interface of electrode/electrolyte. Abstract Water splitting to generate hydrogen is a promising and sustainable process, whereas is limited by the large overpotential of electrode materials for cathode hydrogen evolution reaction (HER) and anode oxygen evolution reaction (OER). Here we present an interface engineering strategy to construct efficient bifunctional electrocatalyst based on (Ni, Fe)S 2 @MoS 2 heterostructrues for water-splitting process. The as-prepared (Ni, Fe)S 2 @MoS 2 catalyst gives remarkable electrochemical activity and durability under alkaline environments, with a low overpotential of 130 mV for HER and 270 mV for OER to deliver the current density of 10 mA cm−2, respectively. In combination with in-situ Raman spectra, we demonstrate that the constructed interfacial active sites are favorable to the formation of S-H ads , which synergistically lower the chemisorption energy of the intermediates of HER and OER, thereby facilitating the electrocatalytic overall water splitting. Furthermore, we regulate the interface of (Ni, Fe)S 2 @MoS 2 and electrolyte through changing the composition of electrolyte to achieve much longer electrochemical stability of this hybrid sulfide electrocatalyst. [ABSTRACT FROM AUTHOR]

Electrochemical hydrogen production coupling upgrading of organic substances has been regarded as a promising approach to harvest both green energy and commodity products. However, the competition of oxygen evolution reaction always limits the transformation of organics and the research on this mutually restricted relationship was less focused. Herein, an amorphous layered double hydroxide (LDH) rich in active oxygen is well-constructed, which realizes the glycerol oxidation with nearly 100 % faradaic efficiency and high formic acid production yield at a current density > 200 mA cm−2. In-situ monitoring combined with electrochemical probe confirms that the active oxygen on the amorphous LDHs promotes the deprotonation of glycerol. To further reduce the energy input, an alkaline-acid hybrid flow cell is built to achieve constant hydrogen production coupling formic acid production at high current density (100 mA cm−1) under an ultra-low cell voltage of 0.90 V with high durability for over 500 h. Moreover, a novel waste oil recycle path is developed to transform waste oil into target value-added products (potassium diformate (KDF) and biodiesel) and hydrogen fuels using the amorphous LDHs electrocatalysts. [Display omitted] • An amorphous layered double hydroxide (A-NiFe-LDH) rich in active oxygen was prepared via electrochemical amorphization. • A-NiFe-LDH can boost electrochemical glycerol oxidation coupling hydrogen production. • The existence of multiple active oxygen species (AOS) and AOS involved oxidation mechanism is uncovered. • A new cycling path of waste oil into target value-added products is designed. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting plays a crucial role in clean and renewable energy production, in which solar-to-chemical energy conversion efficiency is definitively dependent on the charge carrier generation and transfer ability. Here we report a facile and effective method to largely enhance the transfer ability of charge carriers via fabrication of an oxygen vacancy-rich WO x modulated WO 3 photoanode (WO 3 -OV). Experimental studies show that the oxygen vacancies significantly increase the charge carrier density of WO 3 -OV (∼6.89 times larger than that of pristine WO 3 ). Moreover, density functional theory calculations reveal that a WO 3 /WO x heterojunction is formed due to the energy difference between WO 3 and oxygen vacancy-rich layer, which improves the build-in electronic field and reduces the charge recombination. As a result, the WO 3 -OV photoanode gives largely improved charge separation efficiency (67.2%) and a high photocurrent density of 1.35 mA cm −2  at 1.23 V vs. RHE, among the highest level in WO 3 -based materials. It is expected that the surface modulation by oxygen vacancy can be extended to other semiconductor systems for advanced performance in the fields of energy conversion and storage. [ABSTRACT FROM AUTHOR]

Photoelectrochemical conversion of solar energy into fuels (or chemicals) is in urgent need of efficient photoanodes to drive its practical applications. Nevertheless, the development of high performance photoanode usually suffers from slow charge transfer and sluggish surface catalytic kinetics. Here, we report a surface active oxygen engineering strategy through the modification and activation of NiCo layered double hydroxide (NiCo-LDH), where the activated NiCo-LDH (NiCo-LDH-Act) captures the photogenerated holes and acts as cocatalyst for surface oxidation reactions. The as-developed BiVO 4 /NiCo-LDH-Act achieves more than 3-fold higher photocurrent density than that of pristine BiVO 4. Experimental integrated with theoretical studies further testify the bifunctional of NiCo-LDH-Act for hole transport and catalytic reactions. Moreover, the adsorbed ·OH originated from active oxygen enables efficient oxidation of glycerol to attain 1,3-dihydroxyacetone (DHA) with a productivity of 20.5 μmol cm–2 h–1 at 1.4 V vs. RHE with simultaneously producing hydrogen at the cathode. [Display omitted] ● Various cobalt-based LDHs were modified and activated on metal oxide photoanodes. ● Activated NiCo-LDH enables a 3.13-fold improvement in the performance of BiVO 4. ● Surface active oxygen originates from dehydrogenation of hydroxyl groups on LDHs. ● Photoelectrochemical oxidation of glycerol to DHA coupled with hydrogen production. ● Identification and mechanism reveal of adsorbed·OH radical intermediates. [ABSTRACT FROM AUTHOR]

As a safe and environmentally friendly selective hydrogenation method, catalytic transfer hydrogenation (CTH) has aroused great interest in preparation of high-value-added products from biomass derived resources. Herein, a Cu-based catalyst (Cu/CuAl-MMO-400) was prepared by structural topological transformation of layered double hydroxides (LDHs) precursor, which displayed promising catalytic behavior toward CTH reaction of furfural (FAL) with 2-propanol (2-POL) as the hydrogen donor. Notably, the reaction rate is as high as 0.125 mol g−1 h−1, which is superior to previously reported non-noble metal catalysts. A combination investigation based on XPS, XANES and Bader charge confirms the co-existence of Cu0 and Cu+ sites on the surface of Cu nanoparticles. Both experimental studies (in situ DRIFTS and isotope labelling MS) and DFT calculations reveal that the Cu0 − Cu+ synergistic effect plays a vital role in determining catalytic behavior: the Cu+ species acts as both dehydrogenation and hydrogenation active site; while the Cu0 site promotes the transfer of H atoms between adsorbed substrates. This work substantiates a Cu0 −Cu+ synergetic catalysis by establishing structure-property correlation and revealing reaction pathway, which could be extended to other CTH reactions in the upgrading processes of biomass. [Display omitted] • Cu-based catalysts with tunable Cu0/Cu+ ratios were prepared based on layered double hydroxides (LDHs) precursor. • Cu/CuAl-MMO-400 sample exhibits excellent catalytic performance toward catalytic transfer hydrogenation (CTH) reaction. • The CTH reaction of FAL occurs through a metal hydride pathway over the Cu/CuAl-MMO-400 catalyst. • The Cu0 − Cu+ synergistic effect (dual active sites) plays a vital role in determining the catalytic behavior. [ABSTRACT FROM AUTHOR]

The sluggish oxygen evolution reaction (OER) limits the efficiency of overall water splitting, which thereby hinders hydrogen evolution reaction (HER). Here, we demonstrate a bifunctional CoNiP nanosheet integrated electrode (CoNiP-NIE) to boost HER and replace OER by 5-hydroxymethylfurfural oxidation reaction (HMFOR) to obtain high-valued 2,5-furandicarboxylic acid (FDCA). The as-developed CoNiP-NIE exhibits a constant high Faradaic efficiency more than 82% for HMFOR in a wide potential from 1.40 V to 1.70 V vs. RHE, which stand at the top level among the reported electrocatalysts. Moreover, the low overpotential for HER further indicates its high efficiency in the H 2 generation. Based on the bifunctional activity of CoNiP, an electrochemical hydrogen evolution coupled with biomass oxidation device is constructed, which delivers lower voltage (1.46 V) for anode oxidation and higher evolution rate of H 2 (41.2 L h−1 m−2) than water splitting (1.76 V, 16.1 L h−1 m−2). We report a bifunctional CoNiP nanosheet integrated electrode by facile ion etching and subsequent phosphidation process, which shows promising activity for HMFOR and HER simultaneously. This work thus could provide a successful paradigm for rational design bifunctional electrocatalysts for highly efficient hydrogen production coupled with biomass oxidation. [Display omitted] • The CoNiP-NIE exhibits high FE FDCA in a wide potential from 1.40 to 1.70 V vs. RHE. • An EHCO device based on bifunctional CoNiP-NIE enhances the evolution rate of H 2. • CoNiP displays moderate desorption for FDCA and enhanced electrical conductivity. [ABSTRACT FROM AUTHOR]

A more efficient and convenient strategy was demonstrated to immobilize silver nanoparticles (NPs) with a crystalline structure into the spherical polyelectrolyte brushes (SPB) as an antibacterial material. The SPB used for surface coating (Ag immobilized PVK–PAA SPB) consists of a poly(N-vinylcarbazole) (PVK) core and poly(acrylic acid) (PAA) chain layers which are anchored onto the surface of PVK core at one end. Well-dispersed silver nanoparticles (diameter ∼ 3.5 nm) then formed and were electrostatically confined in the brush layer. Ag content is controlled by a repeated loading process. Thin film coatings were then constructed by layer-by-layer depositions of positive charged poly(diallyldimethylammonium chloride) (PDDA) and SPB. The multilayer composites display excellent stability as well as antibacterial performance but not for simple PVK–PAA coated surface. The results show that almost complete bacteria growth including both dispersed bacterial cells and biofilms was inhibited over a period of 24 h. This approach opens a novel strategy for stable and efficient immobilization of Ag NPs in fabrication of antibacterial materials. [ABSTRACT FROM AUTHOR]

[Display omitted] An integrated bifunctional electrocatalyst composed of CoPt nanoparticles uniformly distributed on the carbon nanosheet array is successfully synthesized, which exhibits much enhanced activity for both pH-universal hydrogen evolution and glycerol oxidation. This work demonstrates a successful paradigm for the design and preparation of integrated bifunctional electrocatalyst with potential applications in hydrogen production. • An integrated bifunctional CNs@CoPt electrocatalyst is successfully synthesized. • The CNs@CoPt exhibits superior activity for pH-universal HER and GOR. • A quite high utilization degree of Pt (35.1%) is achieved on CNs@CoPt. • The GOR-HER system based on CNs@CoPt shows boosted hydrogen evolution performance. Exploiting highly effective and low-cost electrocatalyst for water splitting is an instant challenge for the development of sustainable hydrogen energy. In this work, we report an integrated bifunctional electrocatalyst composed of CoPt nanoparticles uniformly distributed on the carbon nanosheet array (CNs@CoPt), which exhibits excellent activity for both cathodic hydrogen evolution in a wide range of pH conditions and anodic glycerol oxidation reaction. Based on this novel electrocatalyst, a hydrogen evolution coupled with glycerol oxidation system was constructed, exhibiting dramatically enhanced hydrogen production rate (48 L h−1 m−2) in cathode, larger than traditional water splitting system (27 L h−1 m−2), and gaining high-valuable product (formate, 113 g h−1 m−2) in anode. Moreover, a quite high utilization degree of Pt (35.1%) is achieved on CNs@CoPt owing to this hierarchical and alloy structure, 3.3 times higher than that of commercial Pt/C (10.6 %). We believe that the strategy demonstrated in this work can be extended to fabricate other multifunctional integrated electrocatalysts with high performance for hydrogen production. [ABSTRACT FROM AUTHOR]

Highlights: [•] Activation energy and solid residue of combustion were lower than that of pyrolysis. [•] Distributed activation energy model is not suitable for combustion kinetics analysis. [•] Distributed E values of pyrolysis increased with the increase of mass conversion. [•] Global kinetic model is suitable for kinetics analysis of combustion and pyrolysis. [•] E value obtained from global kinetic model is lower than that from DAEM. [ABSTRACT FROM AUTHOR]

Abstract: Aluminum-doped α-Ni(OH)2 microspheres with flowerlike hierarchical structure (H-Al-α-Ni(OH)2) were successfully synthesized via a facile hydrothermal method with the assistance of ionic liquid (1-butyl-3-methyl imidazolium tetrafluoroborate, [BMIM]BF4). The XRD pattern and elemental analysis confirm that aluminum species incorporates into the lattice of α-Ni(OH)2; SEM and TEM images reveal that the as-prepared microspheres are composed of numerous frizzy nanoflakes shell attaching vertically to the core. The resulting H-Al-α-Ni(OH)2 sample exhibits a specific surface area of 91.2m2/g and a mesopore distribution (2–20nm) based on the BET measurements. Furthermore, the hierarchical H-Al-α-Ni(OH)2 modified electrode displays a couple of well-defined reversible redox peaks (ΔE p =67mV and I a/I c =0.91) and a fast direct electron transfer rate constant (k s =3.32s−1), owing to the high dispersion of active species as well as abundant mass transfer channels which facilitate the mass/electron transfer. In addition, the modified electrode presents a significant electrocatalytic performance towards the oxidation of hydrazine with a linear response range (5.0×10−6–1.0×10−4 M), high sensitivity (144μA/μM cm2), low detection limit (0.8μM) as well as good stability. The hierarchical α-Ni(OH)2 with largely enhanced electrochemical behavior demonstrated in this work can be used in electrochemical sensor and electroanalysis. [Copyright &y& Elsevier]

Single-atomic-Co cocatalyst on (040) facet of BiVO 4 photoanode were prepared, presenting enhanced charge separation efficiency and nearly 100 % charge injection efficiency. [Display omitted] • BiVO 4 (040) photoanodes with various exposure degree of (040) facets were fabricated. • Single-atomic-cobalt cocatalyst was in-situ grown on BiVO 4 (040) photoanode. • BiVO 4 (040)/Co SAs-NC presented nearly 100% charge injection efficiency. Monoclinic bismuth vanadate (BiVO 4) shows promising application prospect in photoelectrochemical (PEC) water splitting on account of its relatively ideal band gap to harvest sunlight. However, the poor charge migrate property and sluggish water oxidation kinetics severely limit the PEC performance of BiVO 4 photoelectrodes. In this work, BiVO 4 photoanode with highly exposed (040) facets for superior charge transfer was prepared by a seed assisted hydrothermal method. Moreover, cobalt single atoms stabilized in N-doped carbon nanosheet (Co SAs-NC) was well modified on BiVO 4 (040) (denoted as BiVO 4 (040)/Co SAs-NC) with much improved water oxidation efficiency. The as-prepared BiVO 4 (040)/Co SAs-NC photoanode generated 2.2 times higher photocurrent density than that of pristine BiVO 4 (040) at 1.23 V vs. RHE, and presented nearly 100% charge injection efficiency. The detail kinetic measurements reveal that the modified Co SAs-NC cocatalyst effectively suppresses the carrier recombination and promotes the surface reaction kinetics. This work provides a promising strategy to fabricate composite photoanodes for solar energy conversion based on facet engineering matched with single-atomic-catalyst. [ABSTRACT FROM AUTHOR]

Electrochemical organic oxidation into commodity products coupled with hydrogen evolution in aqueous media serves as a promising formulation for harvesting both value-added chemicals and clean energy. However, how to develop electrocatalysts for efficient oxidize organic compounds with depressed side-reaction (oxygen evolution reaction, OER) still remains a challenge. Herein, we report an integrated efficient electrocatalyst for the oxidation of 5-hydroxymethylfurfural (HMF) based on ultrathin layered double hydroxides (LDHs) nanosheet array (NSA) exposed with abundant oxygen vacancies. A high faradaic efficiency at a high potential (99.4% at 1.52 V vs. RHE) is achieved, which implies largely depressed OER process and stands at the highest level compared with previously reported electrocatalysts. Furthermore, A two-electrode electrolyzer was also assembled based on the LDHs NSA, giving rise to a much low voltage for HMF oxidation, a high H 2 yield of 44.16 L h−1 m−2 as well as excellent stability. Ultrathin LDHs nanosheets array was synthesized by electrochemical in-situ exfoliation of bulk LDH array on the conductive substrate, which exhibited largely enhanced electrocatalytic performance towards HMF oxidation. This work demonstrates a successful paradigm for the design and preparation of highly-active LDH nanosheets array with potential applications in commodity chemicals production couple with hydrogen evolution. [Display omitted] • An ultra-thin vacancy-rich CoAl-LDH was prepared via electrochemical exfoliation. • The E-CoAl-LDH-NSA exhibits excellent performance towards oxidation of HMF. • The introduction of vacancy optimizes the adsorption and oxidation process of HMF. • The E-CoAl-LDH-NSA displays a highly enhanced H 2 and FDCA production. [ABSTRACT FROM AUTHOR]