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In both the manufacturing and chemical industries, benzoquinone is a crucial chemical product. A perfect and economical method for making benzoquinone is the electrochemical oxidation of phenol, thanks to the traditional thermal catalytic oxidation of phenol process requires high cost, serious pollution and harsh reaction conditions. Here, a unique heterostructure electrocatalyst on nickel foam (NF) consisting of nickel sulfide and nickel oxide (Ni9S8‐Ni15O16/NF) was produced, and this catalyst exhibited a low overpotential (1.35 V vs. RHE) and prominent selectivity (99 %) for electrochemical phenol oxidation reaction (EOP). Ni9S8‐Ni15O16/NF is beneficial for lowering the reaction energy barrier and boosting reactivity in the EOP process according to density functional theory (DFT) calculations. Additionally, an alkali/acid hybrid flow cell was successfully established by connecting Ni9S8‐Ni15O16/NF and commercial RuIr/Ti in series to catalyze phenol oxidation in an alkaline medium and hydrogen evolution in an acid medium, respectively. A cell voltage of only 0.60 V was applied to produce a current density of 10 mA cm−2. Meanwhile, the system continued to operate at 0.90 V for 12 days, showing remarkable long‐term stability. The unique configuration of the acid‐base hybrid flow cell electrolyzer provides valuable guidance for the efficient and environmentally friendly electrooxidation of phenol to benzoquinone. [ABSTRACT FROM AUTHOR]

Alloying‐type antimony (Sb) with high theoretical capacity is a promising anode candidate for both lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). Given the larger radius of Na+ (1.02 Å) than Li+ (0.76 Å), it was generally believed that the Sb anode would experience even worse capacity degradation in SIBs due to more substantial volumetric variations during cycling when compared to LIBs. However, the Sb anode in SIBs unexpectedly exhibited both better electrochemical and structural stability than in LIBs, and the mechanistic reasons that underlie this performance discrepancy remain undiscovered. Here, using substantial in situ transmission electron microscopy, X‐ray diffraction, and Raman techniques complemented by theoretical simulations, we explicitly reveal that compared to the lithiation/delithiation process, sodiation/desodiation process of Sb anode displays a previously unexplored two‐stage alloying/dealloying mechanism with polycrystalline and amorphous phases as the intermediates featuring improved resilience to mechanical damage, contributing to superior cycling stability in SIBs. Additionally, the better mechanical properties and weaker atomic interaction of Na−Sb alloys than Li−Sb alloys favor enabling mitigated mechanical stress, accounting for enhanced structural stability as unveiled by theoretical simulations. Our finding delineates the mechanistic origins of enhanced cycling stability of Sb anode in SIBs with potential implications for other large‐volume‐change electrode materials. [ABSTRACT FROM AUTHOR]

Sodium borohydride (NaBH4) has earned recognition as a promising hydrogen carrier, attributed to its exceptional hydrogen storage capacity, boasting a high theoretical storage capacity of 10.8 wt %. Nonetheless, the utilization of traditional pyrolysis and hydrolysis methods still presents a formidable challenge in achieving controlled hydrogen generation especially under ambient conditions. In this work, we report an innovative electrochemical strategy for production H2 by coupling NaBH4 electrooxidation reaction (BOR) at anode in alkaline media with hydrogen evolution reaction (HER) at cathode in acidic media. To implement this, we have developed a bifunctional electrocatalyst denoted as Pd‐Mo2C@CNTs, wherein Pd nanoparticles are grown in situ on Mo2C embedded within N‐doped carbon nanotubes. This electrocatalyst demonstrates exceptional performance in catalyzing both alkaline BOR and acidic HER. We have developed a hybrid acid/alkali cell, utilizing Pd/Mo2C@CNTs as the anode and cathode electrocatalysts. This configuration showcases remarkable capabilities for self‐sustained, precise, and uninterrupted indirect release of H2 stored in NaBH4, even at high current densities of 100 mA cm−2 with a Faraday efficiency approaching 100 %. Additionally, this electrochemical device exhibits significant promise as a fuel cell, with the ability to deliver a maximum power density of 20 mW cm−2. [ABSTRACT FROM AUTHOR]

Electrosynthesis of H2O2 has great potential for directly converting O2 into disinfectant, yet it is still a big challenge to develop effective electrocatalysts for medical‐level H2O2 production. Herein, we report the design and fabrication of electrocatalysts with biomimetic active centers, consisting of single atomic iron asymmetrically coordinated with both nitrogen and sulfur, dispersed on hierarchically porous carbon (FeSA‐NS/C). The newly‐developed FeSA‐NS/C catalyst exhibited a high catalytic activity and selectivity for oxygen reduction to produce H2O2 at a high current of 100 mA cm−2 with a record high H2O2 selectivity of 90 %. An accumulated H2O2 concentration of 5.8 wt.% is obtained for the electrocatalysis process, which is sufficient for medical disinfection. Combined theoretical calculations and experimental characterizations verified the rationally‐designed catalytic active center with the atomic Fe site stabilized by three‐coordinated nitrogen atoms and one‐sulfur atom (Fe‐N3S‐C). It was further found that the replacement of one N atom with S atom in the classical Fe‐N4‐C active center could induce an asymmetric charge distribution over N atoms surrounding the Fe reactive center to accelerate proton spillover for a rapid formation of the OOH* intermediate, thus speeding up the whole reaction kinetics of oxygen reduction for H2O2 electrosynthesis. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs), thanks to their adjustable porous structure and abundant build‐in functional motifs, have been recently regarded as promising electrode materials for a variety of batteries. There still remain grand opportunities to further utilizing their merits for developing advanced COFs‐based batteries. In this paper, we propose a hybrid acid/alkali all‐COFs battery by coupling pyrene‐4,5,9,10‐tetraone based COF cathode with anthraquinone based COF anode. In such a hybrid acid/alkali all‐COFs battery, the cathodic COF favorably works in acid with a relatively positive potential, while the anodic COF preferably runs in alkali with a relatively negative potential. It thus can deliver a decently high discharge capacity of 92.97 mAh g−1 with a wide voltage window of 2.0 V, and exhibit high energy density of 74.2 Wh kg−1 along with a considerable cyclic stability over 300 cycles. The development of the proof‐of‐concept all‐COFs battery may drive forward the improvement of newly cost‐effective and performance‐reliable energy storage devices. [ABSTRACT FROM AUTHOR]

WS2 nanosheets hold great promise for a variety of applications yet faces a grand challenge in terms of large‐scale synthesis. We report a reliable, scalable, and high‐yield (>93 %) synthetic strategy to fabricate WS2 nanosheets, which exhibit highly desirable electrocatalytic properties toward both the alkaline sulfion (S2−) oxidation reaction (SOR) and the acidic hydrogen evolution reaction (HER). The findings prompted us to develop a hybrid alkali‐acid electrochemical cell with the WS2 nanosheets as bifunctional electrode catalysts of alkaline anodic SOR and acidic cathodic HER. The proof‐of‐concept device holds promise for self‐power or low‐electricity electrolytic H2 generation and environmentally friendly recycling of sulfion with enhanced electron utilization efficiency. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 (CO2RR) into valuable hydrocarbons is appealing in alleviating the excessive CO2 level. We present the very first utilization of metallic bismuth–tin (Bi‐Sn) aerogel for CO2RR with selective HCOOH production. A non‐precious bimetallic aerogel of Bi‐Sn is readily prepared at ambient temperature, which exhibits 3D morphology with interconnected channels, abundant interfaces and a hydrophilic surface. Superior to Bi and Sn, the Bi‐Sn aerogel exposes more active sites and it has favorable mass transfer properties, which endow it with a high FEHCOOH of 93.9 %. Moreover, the Bi‐Sn aerogel achieves a FEHCOOH of ca. 90 % that was maintained for 10 h in a flow battery. In situ ATR‐FTIR measurements confirmed that the formation of *HCOO is the rate‐determining step toward formic acid generation. DFT demonstrated the coexistence of Bi and Sn optimized the energy barrier for the production of HCOOH, thereby improving the catalytic activity. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen reduction reaction (NRR) plays a vital role for next‐generation electrochemical energy conversion technologies. However, the NRR kinetics is still limited by the sluggish hydrogenation process on noble‐metal‐free electrocatalyst. Herein, we report the rational design and synthesis of a hybrid catalyst with atomic iron sites anchored on a N,O‐doped porous carbon (FeSA‐NO‐C) matrix of an inverse opal structure, leading to a remarkably high NH3 yield rate of 31.9 μgNH3 h−1 mg−1cat. and Faradaic efficiency of 11.8 % at −0.4 V for NRR electrocatalysis, outperformed almost all previously reported atomically dispersed metal‐nitrogen‐carbon catalysts. Theoretical calculations revealed that the observed high NRR catalytic activity for the FeSA‐NO‐C catalyst stemmed mainly from the optimized charge‐transfer between the adjacent O and Fe atoms homogenously distributed on the porous carbon support, which could not only significantly facilitate the transportation of N2 and ions but also effectively decrease the binding energy between the isolated Fe atom and *N2 intermediate and the thermodynamic Gibbs free energy of the rate‐determining step (*N2 → *NNH). [ABSTRACT FROM AUTHOR]

Aqueous rechargeable batteries have attracted attention owning to their advantages of safety, low cost, and sustainability, while the limited electrochemical stability window (1.23 V) of water leads to their failure in competition with organic‐based lithium‐ion batteries. Herein, we report an alkali–acid Zn–PbO2 hybrid aqueous battery obtained by coupling an alkaline Zn anode with an acidic PbO2 cathode. It shows the capability to deliver an impressively high open‐circuit voltage (Voc) of 3.09 V and an operate voltage of 2.95 V at 5 mA cm−2, thanks to the contribution of expanding the voltage window and the electrochemical neutralization energy from the alkali–acid asymmetric‐electrolyte hybrid cell. The hybrid battery can potentially deliver a large area capacity over 2 mAh cm−2 or a high energy density of 252.39 Wh kg−1 and shows almost no fading in area capacity over 250 charge–discharge cycles. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) monometallic pnictogens (antimony or Sb, and bismuth or Bi) nanosheets demonstrate potential in a variety of fields, including quantum devices, catalysis, biomedicine and energy, because of their unique physical, chemical, electronic and optical properties. However, the development of general and high‐efficiency preparative routes toward high‐quality pnictogen nanosheets is challenging. A general method involving a molten‐salt‐assisted aluminothermic reduction process is reported for the synthesis of Sb and Bi nanosheets in high yields (>90 %). Electrocatalytic CO2 reduction was investigated on the Bi nanosheets, and high catalytic selectively to formate was demonstrated with a considerable current density at a low overpotential and an impressive stability. Bi nanosheets continuously convert CO2 into formate in a flow cell operating for one month, with a yield rate of 787.5 mmol cm−2 h−1. Theoretical results suggest that the edge sites of Bi are far more active than the terrace sites. [ABSTRACT FROM AUTHOR]

We report a straightforward strategy to design efficient N doped porous carbon (NPC) electrocatalyst that has a high concentration of easily accessible active sites for the CO2 reduction reaction (CO2RR). The NPC with large amounts of active N (pyridinic and graphitic N) and highly porous structure is prepared by using an oxygen‐rich metal–organic framework (Zn‐MOF‐74) precursor. The amount of active N species can be tuned by optimizing the calcination temperature and time. Owing to the large pore sizes, the active sites are well exposed to electrolyte for CO2RR. The NPC exhibits superior CO2RR activity with a small onset potential of −0.35 V and a high faradaic efficiency (FE) of 98.4 % towards CO at −0.55 V vs. RHE, one of the highest values among NPC‐based CO2RR electrocatalysts. This work advances an effective and facile way towards highly active and cost‐effective alternatives to noble‐metal CO2RR electrocatalysts for practical applications. [ABSTRACT FROM AUTHOR]

Abstract: Developing cost‐effective electrocatalysts for high‐selectivity CO2 electroreduction remains challenging. We herein report a perfluorinated covalent triazine framework (CTF) electrocatalyst that displays very high selectivity in the electroreduction of CO2 to CH4 with a faradaic efficiency of 99.3 % in aqueous electrolyte. Systematic characterization and electrochemical studies, in combination with density functional theory calculations, demonstrate that the presence of both nitrogen and fluorine in the CTF provides a unique pathway that is inaccessible with the individual components for CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Abstract: An alkaline–acid Zn–H2O fuel cell is proposed for the simultaneous generation of electricity with an open circuit voltage of about 1.25 V and production of H2 with almost 100 % Faradic efficiency. We demonstrate that, as a result of harvesting energy from both electrochemical neutralization and electrochemical Zn oxidation, the as‐developed hybrid cell can deliver a power density of up to 80 mW cm−2 and an energy density of 934 Wh kg−1 and maintain long‐term stability for H2 production with an output voltage of 1.16 V at a current density of 10 mA cm−2. [ABSTRACT FROM AUTHOR]

A novel OER electrocatalyst, namely oxygen-incorporated amorphous cobalt sulfide porous nanocubes (A-CoS4.6O0.6 PNCs), show advantages over the benchmark RuO2 catalyst in alkaline/neutral medium. Experiments combining with calculation demonstrate that the desirable O* adsorption energy, associated with the distorted CoS4.6O0.6 octahedron structure and the oxygen doping, contribute synergistically to the outstanding electrocatalytic activity. [ABSTRACT FROM AUTHOR]

A one-pot/one-step synthesis strategy was developed for the preparation of a nitrogen-doped carbon nanoarchitecture with graphene-nanosheet growth on the inner surface of carbon nanotubes (CNTs). The N-graphene/CNT hybrids exhibit outstanding electrocatalytic activity for several important electrochemical reactions as a result of their unique morphology and defect structures, such as high but uniform nitrogen doping, graphene insertion into CNTs, considerable surface area, and the presence of iron nanoparticles. The high-yield synthetic process features high efficiency, low-cost, straightforward operation, and simple equipment. [ABSTRACT FROM AUTHOR]