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Ce2O2CN2 was firstly used as a promoter to improve the catalytic activity and stability of Fe–N–C for the ORR.

Lithium-sulfur (Li-S) batteries with the prominent advantages are greatly expected to be the attractive alternatives in the next-generation energy-storage systems. However, the practical success of Li-S batteries suffers from the shuttle effect and depressed redox kinetics of polysulfides. Herein, for the first time, InOOH nanoparticles are employed as a potent catalytic additive in sulfur electrode to overcome these issues. As demonstrated by the theoretical and experimental results, the strong interactions between the InOOH nanoparticles and sulfur species enable the effective adsorption of polysulfides. More significantly, InOOH nanoparticles not only effectively expedite the reduction of sulfur during the discharge process, but also dramatically accelerate the oxidation of Li

A precisely fabricated conductive MOF incorporating unique host–guest interactions can be used to achieve active-site integration and effective electrocatalytic C–N bond coupling for the synthesis of urea.

Oxygen evolution reaction (OER) as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years. But, it still maintains the challenge to manipulate the geometric and electronic structure during single reaction process under the same conditions. Herein, we report a simple self-template strategy to generate honeycomb-like Ni2P/N,P–C hybrids with preferred electronic architecture. Experiments coupled with theoretical results revealed that the synthesized catalyst has two characteristics: firstly, the unique honeycomb-like morphology not only enables the fully utilization of catalytic active sites but also optimizes the mass/electron transportation pathway, which favor the diffusion of electrolyte to accessible active sites. Secondly, N,P–C substrate, on the one hand, largely contributes the electronic distribution near Fermi level (EF) thus boosting its electrical conductivity. On the other hand, the support effect result in the upshift of d-band center and electropositivity of Ni sites, which attenuates the energy barrier for the adsorption of OH− and the formation of ∗OOH. In consequence, the optimized Ni2P/N,P–C catalysts feature high electrocatalytic activity towards OER (a low overpotential of 252 mV to achieve 10 mA cm−2) and 10 h long-term stability, the outstanding performance is comparable to most of transition metal catalysts. This work gives a innovative tactics for contriving original OER electrocatalysts, inspirng deeper understanding of fabricating catalysts by combining theoretical simulation and experiment design.

We demonstrate a monolithic frequency-modulated continuous-wave (FMCW) lidar chip with an integrated transceiver array based on lens-assisted beam steering (LABS) technology. It enables beam emitting, steering, receiving, and coherent detecting on a single chip with simultaneous distance and velocity detection. An integrated transceiver is designed with a composite structure of a Bragg grating in the middle and a U-shaped photodetector (PD) surrounding it. For a proof-of-concept demonstration, a chip with 2 × 2 switchable transceiver array is fabricated. A monolithic coherent LABS lidar system with a scanning angle of 2.86° and a scanning speed of 5.3 µs is implemented for 5 m ranging and 0.45 m/s velocity detection.

Electrocatalytic C-N bond coupling to convert CO2 and N2 molecules into urea under ambient conditions is a promising alternative to harsh industrial processes. However, the adsorption and activation of inert gas molecules and then the driving of the C-N coupling reaction is energetically challenging. Herein, novel Mott-Schottky Bi-BiVO4 heterostructures are described that realize a remarkable urea yield rate of 5.91 mmol h-1 g-1 and a Faradaic efficiency of 12.55 % at -0.4 V vs. RHE. Comprehensive analysis confirms the emerging space-charge region in the heterostructure interface not only facilitates the targeted adsorption and activation of CO2 and N2 molecules on the generated local nucleophilic and electrophilic regions, but also effectively suppresses CO poisoning and the formation of endothermic *NNH intermediates. This guarantees the desired exothermic coupling of *N=N* intermediates and generated CO to form the urea precursor, *NCON*.

Electrocatalytic C–N coupling reaction by co-activation of both N2 and CO2 molecules under ambient conditions to synthesize valuable urea opens a new avenue for sustainable development, while the actual catalytic activity is limited by poor adsorption and coupling capability of gas molecules on the catalyst surface. Herein, theoretical calculation predicts that the well-developed built-in electric field in perovskite hetero-structured BiFeO3/BiVO4 hybrids can accelerate the local charge redistribution and thus promote the targeted adsorption and activation of inert N2 and CO2 molecules on the generated local electrophilic and nucleophilic regions. Thus, a BiFeO3/BiVO4 heterojunction is designed and synthesized, which delivers a urea yield rate of 4.94 mmol h−1 g−1 with a faradaic efficiency of 17.18% at −0.4 V vs. RHE in 0.1 M KHCO3, outperforming the highest values reported as far. The comprehensive analysis further confirms that the local charge redistribution in the heterojunction effectively suppresses CO poisoning and the formation of the endothermic *NNH intermediate, which thus guarantees the exothermic coupling of *N 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 N* intermediates with the generated CO via C–N coupling reactions to form the urea precursor *NCON* intermediate. This work opens a new avenue for effective electrocatalytic C–N coupling under ambient conditions., The local charge redistribution in BiFeO3/BiVO4 hybrids promotes the targeted adsorption and activation of inert gas molecules and guarantees the exothermic coupling of *NN* with generated CO via C–N coupling reactions to form *NCON* precursor.

An atomically dispersed structure is attractive for electrochemically converting carbon dioxide (CO2) to fuels and feedstock due to its unique properties and activity. Most single-atom electrocatalysts are reported to reduce CO2 to carbon monoxide (CO). Herein, we develop atomically dispersed indium (In) on a nitrogen-doped carbon skeleton (In-N-C) as an efficient catalyst to produce formic acid/formate in aqueous media, reaching a turnover frequency as high as 26771 h-1 at -0.99 V relative to a reversible hydrogen electrode (RHE). Electrochemical measurements show that trace amounts of In loaded on the carbon matrix significantly improve the electrocatalytic behavior for the CO2 reduction reaction, outperforming conventional metallic In catalysts. Further experiments and density functional theory (DFT) calculations reveal that the formation of intermediate *OCHO on isolated In sites plays a pivotal role in the efficiency of the CO2-to-formate process, which has a lower energy barrier than that on metallic In.

Owing to their high energy density and low cost, lithium–sulfur (Li–S) batteries are deemed as promising next-generation energy-storage systems. However, the practical applications of Li–S batteries are still intercepted by the notorious shuttle effect and sluggish reaction kinetics. Herein, a porous nitrogen-doped carbon nanorod embedded with ultrafine Bi nanoparticles (Bi-NC) is constructed to function as an advanced sulfur host. The existence of Bi nanoparticles induces the local charge rearrangement and hence optimizes the electronic structure of Bi-NC. As a result, Bi-NC significantly features the effective chemical adsorption and remarkable redox catalyzation for polysulfides, corroborated by both computational and experimental demonstrations. Profiting from these distinctive superiorities, the enhanced utilization of sulfur species and facilitated redox kinetics of polysulfides are achieved. Therefore, the Bi-NC/S electrode delivers a high initial capacity of 1157 mA h g−1 at 0.5C, a superb capacity retention of 811 mA h g−1 at 1C after 500 cycles, and an excellent areal capacity of 6.48 mA h cm−2 even under a high-sulfur loading of 7.0 mg cm−2. This work affords an innovational regulation of electronic structures via the local charge rearrangement for developing ideal hosts towards the practical high-performance Li–S batteries.

Interaction of the trilacunary 9-tungstosilicate [A-α-SiW9O34]10- with cobalt(ii), nickel(ii) and zinc(ii) ions in pH 9 aqueous medium at room temperature led to the formation of the respective M4-containing heteropolytungstates [M4(OH)3(H2O)2(α-SiW10O36.5)2]13- (M = Co2+ (1), Ni2+ (2), and Zn2+ (3)). Polyanions 1-3 were characterized in the solid state by single-crystal XRD, FT-IR spectroscopy, and thermogravimetric and elemental analyses. Electrochemical studies showed that the Co2+ ions in 1 can be oxidized to Co3+ and the CVs of the WVI centers of the polyanions feature well-defined and chemically reversible reduction waves. Magnetic measurements on 1 and 2 showed paramagnetism with complex ferromagnetic and antiferromagnetic interactions. A model was presented for extracting the exchange constants for the magnetic exchange interaction.

The water oxidation reaction involves a four electron–proton coupled process that is kinetically sluggish and has hindered the widespread application of water-splitting technology. Metal-MOF-coupled heterostructures serve as good OER electrocatalysts due to their endowed MOF frameworks and numerous transition metal active sites at the interface. In this study, a simple ultrasonic impregnation strategy was used to prepare CoOx/UiO-66-300 and NiO/UiO-66-300 heterostructures via the impregnation of Co and Ni ions into UiO-66 followed by roasting in air at 300 °C to obtain heterostructures with UiO-66-retained frameworks as revealed by SEM. The electrochemical results show that the respective impregnation successfully modulated the electronic charge at the interface of the heterostructures, leading to rapid electron transfer that enhanced the OER activity. CoOx/UiO-66-300 and NiO/UiO-66-300 heterostructures showed good oxygen evolution reaction activities of 283 mV and 291.6 mV, respectively, due to the retained UiO-66 framework, while CoOx/UiO-66-550 and NiO/UiO-66-550 heterostructures calcined at 550 °C showed a decrease in OER activities of 332.6 mV and 346.6 mV, respectively, due to the collapsed UiO-66 framework. This work gives insight into the development of heterostructures of MOF-retained frameworks for energy applications.

In this article, we proposed a measurement system that can simultaneously measure temperature and pressure. By analyzing several existing measurement methods of the sensor, we determined that the resonance frequency and $S_{11}$ (reflection coefficient) amplitude of the sensor readout system should be measured when the resonance frequency of the sensor up to a hundred megahertz or even gigahertz and when the sensor works in ultrahigh temperature environment. In addition, we designed a simple and accurate sensor readout circuit and an LC temperature–pressure sensor. By analyzing the resonance frequency and the amplitude of $S_{11}$ , temperature and pressure were measured simultaneously with a single LC circuit. Since the analysis of the whole nonlinear system of sensors is complex, we divide the entire nonlinear system into several linear systems superposition. By analyzing the interference between temperature and pressure, we further optimized the measurement method. The relative errors of the temperature measurements in the range of 25 °C–300 °C and 300 °C–1000 °C were only 2.89% and 1.25%, respectively. From 25 °C to 300 °C and 300 °C to 1000 °C, the average relative errors of pressure measurement were only 4.07% and 4.74%, respectively. Besides, the proposed method can also be widely used in the measurement of LC multiparameter sensors.

The simultaneous electrocatalytic conversion of N2 and CO2 into value-added urea is highly anticipated but suffers from the predicament of the poor chemisorption, activation, and coupling activity of reactant molecules. Herein, unique frustrated Lewis pairs (FLPs) were precisely designed in flower-like nickel borate [Ni3(BO3)2], where the surface hydroxyl and neighboring Ni site serve as a Lewis base and acid, respectively. Comprehensive investigations endorsed that the Lewis basic and acidic sites in FLPs acted synergistically in the targeted capture of inert CO2 and N2 by orbital interaction. Subsequently, the bonding and antibonding orbitals of the inert gas interacted with the empty orbitals of the Lewis acid and nonbonding orbitals of the Lewis base, respectively, achieving molecule activation by FLPs. Afterward, the *NN* and CO intermediates underwent electrocatalytic C–N coupling by the σ orbital carbonylation strategy to produce *NCON* precursors. Thus, the prepared Ni3(BO3)2-150 nanocrystal delivered the record-highest urea yield rate of 9.70 mmol h−1 gcat−1 and a Faradaic efficiency of 20.36% at −0.5 V vs. RHE.

Atomically ordered intermetallic nanomaterials represent one class of the most attractive catalysts for direct alcohol fuel cells, whereas they remain arduous owing to both the complexity of conventional synthetic approaches and their susceptibility to intermediates (especially CO). Herein, a facile one-step surfactant-free strategy is reported for producing Cu-incorporated PtBi intermetallic nanofiber bundles (Cu–PtBi NFBs) served as robust electrocatalysts towards bifunctional methanol and ethanol oxidation reactions (MOR and EOR). The resultant Cu–PtBi NFBs not only achieve remarkable CO tolerance, and superior mass and specific activities (6.79 A mgPt−1 and 11.26 mA cm−2) with a maximum onset potential shift (77 mV) relative to commercial Pt/C for the MOR, but also show 4.3-fold improved EOR mass activity (4.00 A mgPt−1) compared to commercial Pt/C. X-ray absorption fine structure analysis and density functional theory simulation corroborate that the ordered PtBi-based hexagonal close-packed structure, as well as the Cu-induced bifunctional effect, is key to substantially weakening the bonding strength between CO* and Pt sites and strengthening the anchoring of OH* on adjacent Cu sites, thereby optimizing the CO-poisoning pathway. This work provides an effective design strategy for Pt-based intermetallic nano-electrocatalysts as high-efficiency anodic materials in fuel cell applications.

Energy crisis and global warming due to excessive CO2 emissions are the two major challenges of the world. Conversion of CO2 into useful fuels along with rechargeable metal air batteries and water ...

Defect engineering through heteroatom doping is one of the most important strategies towards the development of catalytic active materials for energy related applications. Herein, a novel trifunctional Br/Co/N Co-doped and defect-enriched porous carbon framework (BrHT@CoNC) is designed, which shows excellent electrocatalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as well as the hydrogen evolution reaction (HER). Introduction of extensive defects by heteroatom-doping is simply achieved by pyrolysis of the surfactant, dimethyldioctadecylammonium bromide (DODAB) modified ZIF-67. The BrHT@CoNC composite shows great potential as an economical catalyst/electrode for both rechargeable Zn–air batteries and overall water splitting devices. This work opens a new avenue toward the exploration of cost effective heteroatom doped catalysts for efficient integration of three or more functions into one freestanding electrode.

Cost-effective carbon-based materials are appealing candidates for the electrochemical nitrogen reduction reaction (NRR), while the large bandgap results in a low reactivity and selectivity of the NRR. Work function (W) regulation, altering the electron-transfer ability of carbon materials, is regarded as an encouraging descriptor to enhance the reaction kinetics of the electrochemical NRR, but it has been rarely investigated. To address this issue, Mott–Schottky heterostructural metal/nitrogen-doped carbon nanotubes (M@NCNTs) were designed. Work function theory predicts that systems with a lower W value require smaller extra energy to activate adsorbed N2 molecules. As expected, Ni@NCNTs with the lowest W value displayed the highest faradaic efficiency of 7.33% compared to the other samples. Theoretical simulations and orbital component analysis revealed that different encapsulated metals could tune the work function of M@NCNTs, especially by inducing an upshift of the Fermi level of the outer NCNTs and accelerating the transfer of electrons from the catalyst surface to the adsorbed N2 through the upshifted C–N (π) orbitals, thus guaranteeing the effective activation of N2 molecules. This work provides a guideline for the rational design of NRR catalysts by tuning the work function.

Electrochemical reduction of N2 into NH3 (N2RR) under ambient conditions has emerged as a sustainable approach alternative to the Haber–Bosch process. However, the more favored H+ reduction in aqueous electrolytes can lead to low faradaic efficiency for NH3 production. Thus, designing electrocatalysts to suppress proton reduction is the key to improve the activities towards the N2RR. As an efficient strategy for modulating the associated electronic properties of surface catalysts, the support effect is drawing growing attention. Sparked by the support effect, Ni2P nanoparticles supported by N,P co-doped carbon nanosheets (Ni2P/N,P-C) were synthesized and found to have a higher affinity for N2 molecules than for H+ which makes it a good candidate for the N2RR. The prepared catalyst showed an NH3 yield rate of 34.4 μg h−1 mgNi2P−1 at −0.2 V vs. the reversible hydrogen electrode (RHE) with a faradaic efficiency of 17.21% in 0.1 M HCl (22.89% and 57.2 μg h−1 mgNi2P−1 in 0.2 M PBS; 19.82% and 90.1 μg h−1 mgNi2P−1 in 0.1 M KOH), which is higher than the best values ever reported for noble-metal free catalysts in aqueous solution under ambient conditions. Importantly, the N,P-C substrate in this work is regarded as an electronic storage medium that regulates the electronic distribution of Ni2P/N,P-C when N2 is chemically adsorbed at the Ni site, playing a vital role in inhibiting the adsorption of H and promoting the adsorption and activation of N2 molecules. This work not only gives a new insight into understanding the transformation of the HER to the N2RR, but also provides a guideline for the development of highly active non-noble-metal catalysts.

Polyoxometalate-like molybdenum(vi)-oxo clusters ([Mo-oxo]n, n = 1-20) deposited on high surface-area carbon are developed as a biosensor for non-enzymatic electrochemical H2O2 detection. The sensor exhibits excellent electrocatalytic performance with a low detection limit, wide linear range, excellent sensitivity and stability. The composite can be stably deposited on screen-printed electrodes which combine microlitre analyses, long shelf-life and re-usability.

The top-down fabrication of catalytically active molecular metal oxide anions, or polyoxometalates, is virtually unexplored, although these materials offer unique possibilities, for catalysis, energy conversion and storage. Here, we report a novel top-down route, which enables the scalable synthesis and deposition of sub-nanometer molybdenum-oxo clusters on electrically conductive mesoporous carbon. The new approach uses a unique redox-cycling process to convert crystalline MoIVO2 particles into sub-nanometer molecular molybdenum-oxo clusters with a nuclearity of ∼1–20. The resulting molybdenum-oxo cluster/carbon composite shows outstanding, stable electrocatalytic performance for the oxygen reduction reaction with catalyst characteristics comparable to those of commercial Pt/C. This new material design could give access to a new class of highly reactive polyoxometalate-like metal oxo clusters as high-performance, earth abundant (electro-)catalysts., The top-down synthesis and deposition of polyoxometalate-like clusters on porous carbon is reported together with the high electrocatalytic oxygen reduction reactivity of the composite.

We demonstrate a monolithic transceiver based on a CMOS-compatible silicon photonic platform for lens-assisted beam-steering (LABS) light detecting and ranging (Lidar) application. By implementing an on-chip two-dimensional transceiver array and off-chip lens, beam emitting, steering, and receiving are realized simultaneously on a single chip. The transceiver is designed with a structure of a U-shaped vertical Ge photodetector surrounding a grating for high-efficiency light transmission and reception. The on-chip photodetector has a bandwidth of 87 MHz, a responsivity of 0.3A/W, and a detection sensitivity of − 20 d B m . For proof-of-concept demonstration, a time-of-flight Lidar system is achieved for target ranging with a detection distance of 5.2 m, a scanning angle of 2.86°, and a scanning speed of 5.3 µ s . This work demonstrates a feasible solution to integrated Lidar with beam emitting and receiving on one single chip based on LABS.

Electrochemical sensors for detecting micromolecule organics are desirable for improving the perception of environmental quality and human health. However, currently, the electrochemical sensors for formaldehyde are substantially limited on the market due to the long-term unsolved problems of the low electrooxidation efficiency and CO poisoning issue of commercial Pd catalysts. Here, a 2D Cr-doped Pd metallene (Cr-Pdene) with few atomic layers is shown as an advanced catalyst for ultrasensitive and selective sensing of formaldehyde via a highly efficient formaldehyde electrooxidation. It is found that the doping of Cr into Pd metallene can efficiently optimize the electronic structure of Pd and weaken the interaction between Pd and CO, providing an anti-poisoning means to favor CO2 production and suppress CO adsorption. The Cr-Pdene-based electrochemical sensor exhibits one order of magnitude higher detection range and, especially, much higher anti-interference for formaldehyde than that of the conventional sensors. Most importantly, it is demonstrated that the Cr-Pdene can be integrated into commercializable wireless sensor networks or handheld instruments for promising applications relating to the environment, health, and food.

The degradation of lignin into aromatic products is very important, but harsh conditions and metal-based catalysts are commonly needed to cleave the inert bonds. Herein, an efficient self-initiated radical photochemical degradation for lignin-derived aryl ethers through ionic liquids (ILs) induction is demonstrated. The C-C/C-O bonds can be cleaved efficiently through free-radical-mediated reaction in the binary-ILs system 1-propenyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide [PMim][NTf2 ] and the Bronsted acid 1-propylsulfonic-3-methylimidazolium trifluoromethanesulfonate ([PrSO3 HMim][OTf]) under ambient conditions. [PMim][NTf2 ] initiates the reaction by promoting the cleavage of the Cβ -H bond, and [PrSO3 HMim][OTf] catalyzes the subsequent C-O-C bond fragmentation. Furthermore, alkyl, hydroxyl, and peroxy radicals are detected, which suggests degradation based on a photochemical free-radical process. Additionally, alkali lignin could also be degraded in the IL system. This work sheds light on sustainable biomass utilization through a self-initiated radical photochemical strategy under metal-free and mild conditions.

The oxygen reduction reaction (ORR), which is a crucial process in fuel cells and metal-air batteries, is currently dominated by Pt-based electrocatalysts. However, these catalysts are expensive and rare on Earth; therefore, these factors are considered to impede the widespread commercialization of these technologies. As a consequence, the development of non-Pt catalysts (such as transition-metal materials) with high performance for ORR has become a main focus of research regarding these renewable energy devices. In the present work, a series of porous triazine-based frameworks (PTFs) co-decorated by iron and iodine have been successfully prepared, using different element doping sequences during the synthesis process. The PTF-Fe-I catalysts shows a high ORR activity in both alkaline and acidic media, with an onset potential of 0.95 V (in basic medium) or 0.85 V (in acidic medium) at a loading of 0.3 mg cm–2. This performance not only exceeds that of the dual-doped counterparts (PTF-I-Fe and PTF-(Fe, I)), ...

Laser interaction with targets in fusion can produce significant electromagnetic radiations, which are strongly dependent on the incident laser parameter and target configuration. The electromagnetic pulses generated at a high-power laser facility are recorded and analyzed in terms of propagation in cables and plasma. The attenuation occurs to the radiations in different media and the waveform shows a single peak for the signal close to the laser chamber center, but overlap peaks are observed for the signals measured far away from the center. The distance between peaks is thus analyzed to predict the electromagnetic features and plasma density.

While converting carbon dioxide (CO2) into value-added carbon products by electrolyzing offers a promising approach to mitigate global warming and store energy, poor selectivity and stability of catalysts still impede this conversion. Single-atom catalyst exhibits exceptional selectivity for CO2 electroreduction reaction in response to inhibiting hydrogen evolution reaction (HER), which is the major obstacle to the development of CO2 reduction. Herein we introduce a facile approach to obtain Ni-Nx sites encapsulating into carbon nanotubes with a nickel loading as high as 6.63 wt%. This catalyst exhibits high Faradaic efficiency approximately 95% for CO2 electroreduction to carbon monoxide (CO) in the wide potential range from −0.7 to −1.0 V, and the current density reaches 57.1 mA cm−2 at −1.0 V versus a reversible hydrogen electrode (RHE). Experiments and characterization results demonstrate that nickel chemical state and content play a vital role for CO2 electrocatalytic performance. Moreover, the simplifying of the synthesis may shed a new light on design single atom catalysts of electrochemistry in addition to CO2 reduction.

A novel temperature and pressure measuring scheme based on LC sensor for ultra-high temperature environment is presented here. This method resolves the interference of the temperature drift of the HTCC LC pressure sensor and avoids magnetic field crosstalk between two sets of LC circuits. The scheme is that the temperature is expressed by the amplitude of the resonant frequency of an input return loss curve (S11). And then, the temperature and the resonant frequency are combined to calculate the pressure value. According to this idea, the sensor is manufactured. The sensor is composed of high temperature co-fired ceramics (HTCC) substrate and platinum LC circuit based on screen-printing technology. The platinum circuit consists of a planar spiral inductor(L) and four parallel plate capacitors(C). The external antenna is coupled to the inductor of the sensor to form a device whose impedance is measured by the network analyzer to generate an input return loss curve (S11). The testing principle is to utilize the thermistor characteristics of platinum and the pressure-sensitive properties of airtight cavities. The amplitude of the resonant frequency of S11 is mainly affected by the platinum resistance of the sensor, and the pressure has a reduced influence on the amplitude with elevating temperature. The maximum pressure sensitivity measured is 23.735kHz / kPa at 1200°C in the pressure range of 50kPa to 300kPa. The temperature sensitivity is 0.009dB/°C from 25°C to 1200°C. The impedance variation of the sensor and the XRD and SEM analysis of the platinum film conductor were analyzed.

Single-atom electrocatalysts have attracted board interest in the recent years as they combine the advantages of heterogeneous and homogeneous electrocatalysts. Nevertheless, single-atom electrocatalysts with single metal component cannot further satisfy the demand of catalytic properties. This work developed atomic Co/Ni dual sites in N-doped porous carbon Janus-like frameworks through epitaxial growth of cobalt based MOFs on nickel complexes. Structural characterization and atomic-scale transmission electron microscopy revealed the homogeneously dispersed active sites of Co-Ni alloy and single Co/Ni atoms. Electrochemical data strongly demonstrated the advantages of integrating Co-MOF and Ni complex with different topological structures to form a Janus-like structure. The resultant catalysts afforded onset potential of 0.93 V and half-wave potential of 0.84 V for oxygen reduction reaction in alkaline media, and 0.86 V and 0.73 V in acid media, which is better than single noble-metal-free catalysts, even close to commercial Pt/C. Besides, the catalysts also exhibited good oxygen evolution reaction performance (a current density of 10 mA cm−2 at a potential of 1.59 V) and overvoltage between ORR and OER is 0.78 V. Density functional theory calculations indicated the high electrocatalytic activities are originated from the synergetic effect of atomic Co/Ni-N-C bonds and microstructure of the prepared materials. This work paves a new avenue for the development of multiatomic electrocatalysts for energy conversion.

Electrochemically converting carbon dioxide (CO2) to formate offers a promising approach for energy conversion and storage. Bismuth is believed to be one of the promising candidates for CO2 electroreduction, but the poor selectivity and complexity of synthesis limit its real application on a large scale. In this work, a facile one-step-reduction method was developed to prepare a bismuth nanostructure in aqueous solution. Owing to its enhanced reactive sites and exposed crystal plane, the prepared Bi nanostructure exhibits excellent performance for CO2 electroreduction, which reaches the maximum faradaic efficiency for formate as high as 92% at a potential of -0.9 V versus a reversible hydrogen electrode. Additionally, the large current density and remarkable durability also reveal its high intrinsic CO2 electroreduction activity. The density functional theory calculation confirms that the formation of intermediate *OCHO that finally converts to formate is thermodynamically favorable on Bi high-index planes. We anticipate that such a facile synthesis strategy and excellent electrocatalytic performance of the Bi nanostructure will be easy to scale up, realizing its industrialization applications in CO2 electrochemical conversion.

The electrochemical oxygen evolution reaction (OER) is sparked extensive interest in efficient energy storage and conversion. Cobalt Selenide (CoSe2) is believed to be one of the promising candidates for OER based on Yang Shao-Horn's principle. However, owing to low exposure of active sites and/or low efficiency of electron transfer, the electrocatalytic activity of CoSe2 is far less than expected. In this work, a novel carbon nanotubes (CNT) grafted 3D core-shell structured CoSe2@C-CNT nanohybrid is developed by a general hydrothermal-calcination strategy. Zeolite imidazole frameworks (ZIF) was used as the precursor to synthesis of the materials. It is found that both the calcination temperature and the selenium content can significantly regulate the catalytic performance of the hybrids. The obtained best catalysts requires the overpotential of only 306 mV and 345 mV to reach a current density of 10 mA cm−2 and 50 mA cm−2 in 1.0 MKOH medium, respectively. It also exhibits a small Tafel slope of 46 mV dec−1 and excellent durability, which is superior to most of recently reported CoSe2-based and Co-based materials. These superior performances can be ascribed to synergistic effects of the highly active CoSe2 nanostructure, defect carbon species and the carbon nanotubes exist in the catalyst. Besides, the unique morphology leads to large electrochemical surface area of the catalyst, which is in favor of the exposure of active sites for OER. Due to high efficiency, low cost and excellent durability for OER, the prepared catalysts showed can be potentially used to substitute noble metals utilized in related energy storage and conversion devices.

The oxygen evolution reaction (OER) is a half reaction of electrochemical water splitting that suffers from a kinetically sluggish four-electron process, and it is regarded as the efficiency-limiting step in water splitting. Herein, heterostructures of CoSe (cobalt selenide) nanoparticles and MoSe2 (molybdenum selenide) nanosheets (CoSe/MoSe2 hybrids) were fabricated through a non-metal-induced growth method. Due to the increase in the effective specific area and the electron transfer ability caused by the formation of the heterogeneous interface, the obtained CoSe/MoSe2 hybrids show superior OER performance (η = 262 mV at 10 mA cm−2) and long-term stability (20 h for continuous testing) as compared to pure CoSe, MoSe2 and physically mixed CoSe and MoSe2. Schematic energy band diagrams derived from ultraviolet photoelectron spectroscopy results further confirmed the electronic modulation between CoSe and MoSe2 and revealed that the d-band center of CoSe/MoSe2 hybrids moved closer to the Fermi level, giving rise to high charge carrier density and low intermediate adsorption energy as compared to CoSe and MoSe2. This work provides some insight into the design and synthesis of heterostructured nanomaterials from the MOF precursors.

The development of efficient hydrogen evolution and oxygen evolution reactions bifunctional electrocatalyst for overall water splitting is highly desired but still a great challenge, especially under neutral condition. With the unique properties of polyoxometalate and MOFs materials as well as rich transition metal contents, herein we successfully synthesize a novel bi-phase structure of cobalt and molybdenum carbide coated with nitrogen-doped graphite (Co-Mo2C@NC) which possesses excellent activity as water splitting electrocatalyst at neutral pH. This noble metal-free, bi-phase electrocatalyst exhibits Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) overpotentials of 260 mV and 440 mV at 10 mA cm−2, respectively. The two-electrode system using Co-Mo2C@NC as both the anode and cathode drives 10 mA cm−2 at a cell voltage of 1.83 V with a remarkable long-term stability. Besides, the Co-Mo2C@NC also shows promising activity in alkaline condition that reaches 10 mA cm−2 at a cell voltage of 1.66 V. This work paves a new avenue to the design of the unique, economic and promising non-noble metal electrode materials for practical applications in the electrochemical energy storage and conversion devices.

Lithium–sulfur (Li–S) batteries are greatly expected to be the favored alternatives in the next-generation energy-storage technologies due to their exceptional advantages. However, the shuttle effect and sluggish reaction kinetics of polysulfides largely hamper the practical success of Li–S batteries. Herein, a unique iron carbide (Fe3C) nanoparticles-embedded porous biomass-derived carbon (Fe3C-PBC) is reported as the excellent immobilizer and promoter for polysulfides regulation. Such a distinctive composite strongly couples the vast active sites of Fe3C nanoparticles and the conductive network of porous biomass-derived carbon. Therefore, Fe3C-PBC is endowed with outstanding adsorptivity and catalytic effect toward inhibiting the shuttle effect and facilitating the redox kinetics of polysulfides, demonstrated by the detailed experimental demonstrations and theoretical calculation. With these synergistic effects, the Fe3C-PBC/S electrode embraces a superb capacity retention of 82.7% at 2C over 500 cycles and an excellent areal capacity of 4.81 mAh cm−2 under the high-sulfur loading of 5.2 mg cm−2. This work will inspire the design of advanced hosts based on biomass materials for polysulfides regulation in pursuing the superior Li–S batteries.