An Illumination‐Assisted Flexible Self‐Powered Energy System Based on a Li–O2 Battery

The flexible Li‐O₂ battery is suitable to satisfy the requirements of a self‐powered energy system, thanks to environmental friendliness, low cost, and high theoretical energy density. Herein, a flexible porous bifunctional electrode with both electrocatalytic and photocatalytic activity was synthesized and introduced as a cathode to assemble a high‐performance Li‐O₂ battery that achieved an overpotential of 0.19 V by charging with the aid of solar energy. As a proof‐of‐concept application, a flexible Li‐O₂ battery was constructed and integrated with a solar cell via a scalable encapsulate method to fabricate a flexible self‐powered energy system with excellent flexibility and mechanical stability. Moreover, by exploring the evolution of the electrode morphology and discharge products (Li₂O₂), the charging process of the Li‐O₂ battery powered by solar energy and solar cell was demonstrated.     

Transition Metal (Mn,Fe, Co,Ni)‐Doped Graphene Hybrids for Electrocatalysis

The development of electrocatalysts is crucial for renewable energy applications. Metal‐doped graphene hybrid materials have been explored for this purpose, however, with much focus on noble metals, which are limited by their low availability and high costs. Transition metals may serve as promising alternatives. Here, transition metal‐doped graphene hybrids were synthesized by a simple and scalable method. Metal‐doped graphite oxide precursors were thermally exfoliated in either hydrogen or nitrogen atmosphere; by changing exfoliation atmospheres from inert to reductive, we produced materials with different degrees of oxidation. Effects of the presence of metal nanoparticles and exfoliation atmosphere on the morphology and electrocatalytic activity of the hybrid materials were investigated using electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy, and cyclic voltammetry. Doping of graphene with transition metal nanoparticles of the 4th period significantly influenced the electrocatalysis of compounds important in energy production and storage applications, with hybrid materials exfoliated in nitrogen atmosphere displaying superior performance over those exfoliated in hydrogen atmosphere. Moreover, nickel‐doped graphene hybrids displayed outstanding electrocatalytic activities towards reduction of O₂ when compared to bare graphenes. These findings may be exploited in the research field of renewable energy.     

Boron‐Dependency of Molybdenum Boride Electrocatalysts for the Hydrogen Evolution Reaction

Molybdenum‐based materials have been considered as alternative catalysts to noble metals, such as platinum, for the hydrogen evolution reaction (HER). We have synthesized four binary bulk molybdenum borides Mo₂B, α‐MoB, β‐MoB, and MoB₂ by arc‐melting. All four phases were tested for their electrocatalytic activity (linear sweep voltammetry) and stability (cyclic voltammetry) with respect to the HER in acidic conditions. Three of these phases were studied for their HER activity and by X‐ray photoelectron spectroscopy (XPS) for the first time; MoB₂ and β‐MoB show excellent activity in the same range as the recently reported α‐MoB and β‐Mo₂C phases, while the molybdenum richest phase Mo₂B show significantly lower HER activity, indicating a strong boron‐dependency of these borides for the HER. In addition, MoB₂ and β‐MoB show long‐term cycle stability in acidic solution.     

Phase‐Selective Syntheses of Cobalt Telluride Nanofleeces for Efficient Oxygen Evolution Catalysts

Cobalt‐based nanomaterials have been intensively explored as promising noble‐metal‐free oxygen evolution reaction (OER) electrocatalysts. Herein, we report phase‐selective syntheses of novel hierarchical CoTe₂ and CoTe nanofleeces for efficient OER catalysts. The CoTe₂ nanofleeces exhibited excellent electrocatalytic activity and stablity for OER in alkaline media. The CoTe₂ catalyst exhibited superior OER activity compared to the CoTe catalyst, which is comparable to the state‐of‐the‐art RuO₂ catalyst. Density functional theory calculations showed that the binding strength and lateral interaction of the reaction intermediates on CoTe₂ and CoTe are essential for determining the overpotential required under different conditions. This study provides valuable insights for the rational design of noble‐metal‐free OER catalysts with high performance and low cost by use of Co‐based chalcogenides.     

Round‐the‐Clock Photocatalytic Hydrogen Production with High Efficiency by a Long‐Afterglow Material

Long afterglow materials can store and release light energy after illumination. A brick‐like, micrometer‐sized Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ long‐afterglow material is used for hydrogen production by the photocatalytic reforming of methanol under round‐the‐clock conditions for the first time, achieving a solar‐to‐hydrogen (STH) conversion efficiency of 5.18 %. This material is one of the most efficient photocatalysts and provides the possibility of practical use on a large scale. Its remarkable photocatalytic activity is attributed to its unique carrier migration path and large number of lattice defects. These findings expand the application scope of long afterglow materials and provide a new strategy to design efficient photocatalysts by constructing trap levels that can prolong carrier lifetimes.     

An Amorphous Noble‐Metal‐Free Electrocatalyst that Enables Nitrogen Fixation under Ambient Conditions

N₂ fixation by the electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is regarded as a potential approach to achieve NH₃ production, which still heavily relies on the Haber–Bosch process at the cost of huge energy and massive production of CO₂. A noble‐metal‐free Bi₄V₂O₁₁/CeO₂ hybrid with an amorphous phase (BVC‐A) is used as the cathode for electrocatalytic NRR. The amorphous Bi₄V₂O₁₁ contains significant defects, which play a role as active sites. The CeO₂ not only serves as a trigger to induce the amorphous structure, but also establishes band alignment with Bi₄V₂O₁₁ for rapid interfacial charge transfer. Remarkably, BVC‐A shows outstanding electrocatalytic NRR performance with high average yield (NH₃: 23.21 μg h^?1 mg^?1_cat., Faradaic efficiency: 10.16 %) under ambient conditions, which is superior to the Bi₄V₂O₁₁/CeO₂ hybrid with crystalline phase (BVC‐C) counterpart.     

Scalable Low‐Cost SnS2 Nanosheets as Counter Electrode Building Blocks for Dye‐Sensitized Solar Cells

A new type of semitransparent SnS₂ nanosheet (NS) films were synthesized using a simple and environmentally friendly solution‐processed approach, which were subsequently used as a counter electrode (CE) alternative to the noble metal Pt for triiodide reduction in dye‐sensitized solar cells (DSSCs). The resultant SnS₂‐based CE with a thickness of about 300 nm exhibited excellent electrochemical catalytic activity for catalyzing the reduction of triiodide and demonstrated comparable power conversion efficiency of 7.64 % with that of expensive Pt‐based CE in DSSCs (7.71 %). When functionalized with a small amount of carbon nanoparticles, the SnS₂ NS‐based CE showed even better performance of 8.06 % than Pt under the same conditions. Considering the facile fabrication method, optical transparency, low cost, and remarkable catalytic property, this study on SnS₂ NSs may shed light on the large‐scale production of electrocatalytic electrode materials for low‐cost photovoltaic devices.     

Antimony‐Based Composites Loaded on Phosphorus‐Doped Carbon for Boosting Faradaic Efficiency of the Electrochemical Nitrogen Reduction Reaction

A nanocomposite of PC/Sb/SbPO₄ (PC, phosphorus‐doped carbon) exhibits a high activity and an excellent selectivity for efficient electrocatalytic conversion of N₂ to NH₃ in both acidic and neutral electrolytes under ambient conditions. At a low reductive potential of ?0.15 V versus the reversible hydrogen electrode (RHE), the PC/Sb/SbPO₄ catalyst achieves a high Faradaic efficiency (FE) of 31 % for ammonia production in 0.1 m HCl under mild conditions. In particular, a remarkably high FE value of 34 % is achieved at a lower reductive potential of ?0.1 V (vs. RHE) in a 0.1 m Na₂SO₄ solution, which is better than most reported electrocatalysts towards the nitrogen reduction reaction (NRR) in neutral electrolyte under mild conditions. The change in surface species and electrocatalytic performance before and after N₂ reduction is explored by an ex situ method. PC and SbPO₄ are both considered as the active species that enhanced the performance of NRR.     

Ultrathin MoS2 Nanosheets Supported on N‐doped Carbon Nanoboxes with Enhanced Lithium Storage and Electrocatalytic Properties

Molybdenum disulfide (MoS₂) has received considerable interest for electrochemical energy storage and conversion. In this work, we have designed and synthesized a unique hybrid hollow structure by growing ultrathin MoS₂ nanosheets on N‐doped carbon shells (denoted as C@MoS₂ nanoboxes). The N‐doped carbon shells can greatly improve the conductivity of the hybrid structure and effectively prevent the aggregation of MoS₂ nanosheets. The ultrathin MoS₂ nanosheets could provide more active sites for electrochemical reactions. When evaluated as an anode material for lithium‐ion batteries, these C@MoS₂ nanoboxes show high specific capacity of around 1000 mAh g^?1, excellent cycling stability up to 200 cycles, and superior rate performance. Moreover, they also show enhanced electrocatalytic activity for the electrochemical hydrogen evolution.     

Development of Quantum Dots Modified Acetylcholinesterase Biosensor for the Detection of Trichlorfon

Poly (N‐vinyl‐2‐pyrrolidone) (PVP)‐capped CdS quantum dots (QCdS‐PVP) was synthesized with CdCl₂ and Na₂S in the presence of PVP. QCdS‐PVP has been used for the immobilization and stabilization of the acetylcholinesterase (AChE). The electrocatalytic activity of QCdS‐PVP leads to a greatly improved electrochemical detection of the enzymatically generated thiocholine product, and higher sensitivity and stability. The GCE/QCdS‐PVP/AChE biosensor was used for the detection of organophosphate pesticides (OPs), such as trichlorfon. The sensor performance, including pH and inhibition time, was optimized with respect to operating conditions. Under the optimal conditions, the biosensor was used to measure as low as 12 ppb trichlorfon with a 5‐min inhibition time.     

Trimetallic Oxyhydroxide Coralloids for Efficient Oxygen Evolution Electrocatalysis

Trimetallic oxyhydroxides are one of the most effective materials for oxygen evolution reaction (OER) catalysis, a key process for water splitting. Herein, we describe a facile wet‐chemical method to directly grow a series of coralloid trimetallic oxyhydroxides on arbitrary substrates such as nickel foam (NF) and carbon nanotubes (CNTs). The amount of iron in these oxyhydroxide sponges on NF and CNTs was precisely controlled, revealing that the electrocatalytic activity of the WCoFe trimetallic oxyhydroxides depends on the Fe amount in a volcano‐like fashion. The optimized W_0.5Co_0.4Fe_0.1/NF catalyst exhibited an overpotential of only 310 mV to deliver a large current density of 100 mA cm⁻² and a very low Tafel slope of 32 mV dec⁻¹. It also showed superior stability with negligible activity decay after use in the OER for 21 days (>500 h). X‐ray photoelectron spectroscopy revealed that the addition of Fe leads to an on average lower Co oxidation state, which contributes to the enhanced OER performance.     

Comparison of morphology, stability and electrocatalytic properties of Ru0.3Ti0.7O2 and Ru0.3Ti0.4Ir0.3O2 coated titanium anodes

This paper presents the comparative study of two dimensionally stable anodes (DSA?) of nominal composition Ti/Ru_0.3Ti_0.7O₂ and Ti/Ru_0.3Ti_0.4Ir_0.3O₂, prepared by thermal decomposition of the chloride precursor mixtures at 450°C. The materials were studied by scanning electron microscopy (SEM), cyclic voltammetry and Tafel measurements to obtain information about their surface and electrocatalytic properties towards Cl₂ evolution reaction. The stability of the prepared anodes was investigated under accelerated conditions. It has been observed that the coating surface with 30% mole IrO₂ possesses more compact structure with less cracks. Furthermore, it had excellent electrocatalytic activity for the chlorine evolution. Accelerated stability tests showed long lifetime for Ti/Ru_0.3Ti_0.4Ir_0.3O₂ electrode. On the other hand, besides the excellent improvement of catalytic activity, the stability of the ternary oxide electrode increases compared to the binary oxide one. The deactivation rate appeared to be a consequence of the different morphology and synergetic effects of the prepared coatings.     

Nanocrystal/Metal–Organic Framework Hybrids as Electrocatalytic Platforms for CO2 Conversion

The tunable chemistry linked to the organic/inorganic components in colloidal nanocrystals (NCs) and metal–organic frameworks (MOFs) offers a rich playground to advance the fundamental understanding of materials design for various applications. Herein, we combine these two classes of materials by synthesizing NC/MOF hybrids comprising Ag NCs that are in intimate contact with Al‐PMOF ([Al₂(OH)₂(TCPP)]) (tetrakis(4‐carboxyphenyl)porphyrin (TCPP)), to form Ag@Al‐PMOF. In our hybrids, the NCs are embedded in the MOF while still preserving electrical contact with a conductive substrate. This key feature allows the investigation of the Ag@Al‐PMOFs as electrocatalysts for the CO₂ reduction reaction (CO₂RR). We show that the pristine interface between the NCs and the MOFs accounts for electronic changes in the Ag, which suppress the hydrogen evolution reaction (HER) and promote the CO₂RR. We also demonstrate a minor contribution of mass‐transfer effects imposed by the porous MOF layer under the chosen testing conditions. Furthermore, we find an increased morphological stability of the Ag NCs when combined with the Al‐PMOF. The synthesis method is general and applicable to other metal NCs, thus revealing a new way to think about rationally tailored electrocatalytic materials to steer selectivity and improve stability.     

High Phase‐Purity 1T‐MoS2 Ultrathin Nanosheets by a Spatially Confined Template

The crystal phase plays an important role in controlling the properties of a nanomaterial; however, it is a great challenge to obtain a nanomaterial with high purity of the metastable phase. For instance, the large‐scale synthesis of the metallic phase MoS₂ (1T‐MoS₂) is important for enhancing electrocatalytic reaction, but it can only be obtained under harsh conditions. Herein, a spatially confined template method is proposed to synthesize high phase‐purity MoS₂ with a 1T content of 83 %. Moreover, both the confined space and the structure of template will affect the purity of 1T‐MoS₂; in this case, this approach was extended to other similar spatially confined templates to obtain the high‐purity material. The obtained ultrathin nanosheets exhibit good electrocatalytic activity and excellent stability in the hydrogen evolution reaction.     

Three‐Dimensional Macroporous NiCo2O4 Sheets as a Non‐Noble Catalyst for Efficient Oxygen Reduction Reactions

A facile and low‐cost strategy is developed to prepare three‐dimensional (3D) macroporous NiCo₂O₄ sheets, which can be used as a highly efficient non‐noble metal electrocatalyst for the oxygen reduction reaction (ORR) in alkaline conditions. The as‐obtained sheets have a thickness of about 150 nm and feature a typical 3D macroporous structure with pore volumes of up to 0.23 cm³ g^?1, which could decrease the mass transport resistance and allow easier access of the reactants to the active surface sites. The as‐prepared macroporous NiCo₂O₄ sheets exhibit high electrocatalytic activity for ORR with a four‐electron pathway, good long‐term stability and high tolerance against methanol. The unique 3D macroporous structure and intrinsic properties may be responsible for their high performance.     

Electrocatalytic Reduction of Oxygen at Anthraquinonedisulfonate/Polypyrrole Composite Film Modified Electrodes and Its Application to the Electrochemical Oxidation of Azo Dye

We report here the electrocatalytic reduction of oxygen on thin anthraquindisulfonate (AQDS)/poplypyrrole (PPy) composite film modified electrodes and its application to the electrooxidation of azo dye‐amaranth. The polymer‐coated cathode exhibited good electrocatalytic activity towards oxygen reduction reaction (ORR), and allowed the formation of strong oxidant hydroxyl radical (^.OH) in the medium via Electro‐Fenton's reaction between cathodically generated H₂O₂ and added or regenerated Fe²⁺. The electrochemical behaviors of ORR in various pH solutions were described using cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometric (CA) techniques. The effect of solution pH on amaranth mineralization by the Fe²⁺/H₂O₂ and Fe³⁺/H₂O₂ electrooxidation systems was studied. In addition, the long‐term electrocatalytic activity and stability of the AQDS/PPy composite film during multiple experimental runs were also examined electrochemically.     

Inorganic‐organic Microporous Solid of Wells‐Dawson Type Polyoxometalate: Synthesis,Characterization, and Electrochemical Properties

An inorganic‐organic hybrid solid (H_6/5bppy)₅[P₂W₁₈O₆₂]·4.5H₂O ( 1 ) (bppy = 4‐(5‐(4‐bromophenyl)pyridin‐2‐yl)pyridine) was hydrothermally synthesized by using pre‐constructed Wells‐Dawson type salt α‐K₆P₂W₁₈O₆₂·15H₂O as inorganic moiety. The crystal structure keeps integrated and steady under the interactions together of aryl packing, hydrogen bonding and halogen bonding. X‐ray single crystal structure analysis reveals that compound 1 contains cavities with the sizes of about 6 × 8Å, in which H₂O molecules are captured. The hybrid was used as a solid bulk modifier to fabricate a three‐dimensional bulk‐modified carbon paste electrode ( 1 ‐CPE) by direct mixing. The electrochemical and electrocatalytic behavior of the 1 ‐CPE has been studied in detail. The results exhibit that the redox ability of the Wells‐Dawson polyanions can be maintained in the hybrid solid, which has a good electrocatalytic activity toward the reduction of bromate and hydrogen peroxide. A hydrodynamic voltammetric experiment was performed to characterize the electrode as an amperometric sensor for the determination of hydrogen peroxide. The 1 ‐CPE showed long‐term stability and excellent reproducibility of surface renewal.     

Mediatorless Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Immobilized on 4‐Carboxyphenyl Film Electrografted on Gold Electrode

A novel method to fabricate a third‐generation hydrogen peroxide biosensor was reported. The electrode was first derivatized by electrochemical reduction of in situ generated 4‐carboxyphenyl diazonium salt (4‐CPDS) in acidic aqueous solution yielded stable 4‐carboxyphenyl (4‐CP) layer. The horseradish peroxidase (HRP) enzyme was then covalently immobilized by amidation between NH₂ terminus of enzyme and COOH terminus of 4‐CP film making use of the carbodiimide chemistry. Electrodeposition conditions used to control electrode functionalization density and film electron transfer kinetics were assessed by chronoamperometry and electrochemical impedance spectroscopy. The immobilized HRP displayed excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H₂O₂) without any mediators. The effect of various operational parameters was explored for optimum analytical performance. The reported biosensor exhibited fast amperometric response (within 5 s) to H₂O₂. The detection limit of the biosensor was 5 μM, and linear range was from 20 μM to 20 mM. Furthermore, the biosensor exhibited high sensitivity, good reproducibility, and long‐term stability.     

Heterostructures Composed of N‐Doped Carbon Nanotubes Encapsulating Cobalt and β‐Mo2C Nanoparticles as Bifunctional Electrodes for Water Splitting

Herein, we demonstrate the use of heterostructures comprised of Co/β‐Mo₂C@N‐CNT hybrids for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline electrolyte. The Co can not only create a well‐defined heterointerface with β‐Mo₂C but also overcomes the poor OER activity of β‐Mo₂C, thus leading to enhanced electrocatalytic activity for HER and OER. DFT calculations further proved that cooperation between the N‐CNTs, Co, and β‐Mo₂C results in lower energy barriers of intermediates and thus greatly enhances the HER and OER performance. This study not only provides a simple strategy for the construction of heterostructures with nonprecious metals, but also provides in‐depth insight into the HER and OER mechanism in alkaline solution.     

Fe/Co‐based Bimetallic MOF‐derived Co3Fe7@NCNTFs Bifunctional Electrocatalyst for High‐Efficiency Overall Water Splitting

Electrocatalytic water splitting to produce hydrogen and oxygen is regarded as one of the most promising methods to generate clean and sustainable energy for replacing fossil fuels. However, the design and development of an efficient bifunctional catalyst for simultaneous generation of hydrogen and oxygen remains extremely challenging yet is critical for the practical implementation of water electrolysis. Here, we report a facile method to fabricate novel N‐doped carbon nanotube frameworks (NCNTFs) by the pyrolysis of a bimetallic metal organic framework (MIL‐88‐Fe/Co). The resultant electrocatalyst, Co₃Fe₇@NCNTFs, exhibits excellent oxygen evolution reaction (OER) activity, achieving 10 mA/cm² at a low overpotential of just 264 mV in 1 M KOH solution, and 197 mV for the hydrogen evolution reaction. The high electrocatalytic activity arises from the synergistic effect between the chemistry of the Co₃Fe₇ and the NCNTs coupled to the novel framework structure. The remarkable electrocatalytic performance of our bifunctional electrocatalyst provides a promising pathway to high‐performance overall water splitting and electrochemical energy devices.