Rational Design of Different Morphologies of Ammonium Vanadium-Chromium Oxide Nanostructures: Mechanistic Insights and Ammonium Storage.

At the nanoscale, control over size, composition, and morphology is paramount, representing the ultimate challenge in material design. In this study, we report a synthesis of ammonium vanadium-chromium oxide nanomaterials by controlling temperature and the precursor addition order. A hydrothermal process enables the formation of three distinct morphologies, nanosheets, nanowires, and nanoflowers, each exhibiting a layered structure with integrated ammonium and oxygen defects.

Light-Driven Chemical Cascade Reduces Barriers to Hydrogen Production.

Photocatalysis offers an opportunity for sustainable hydrogen and chemical production. Traditional systems require semiconductors with very specific conduction-band (CB) properties and expensive noble metal cocatalysts, limiting material availability and increasing costs. Here, we introduce an alternative photocatalytic pathway that bypasses these constraints, producing hydrogen and formic acid via a cascade process.

Energy-Efficient Hydrogen Generation via Peroxide-Mediated Electrocatalytic Pathways.

Hydrogen (H) production through water electrolysis is a promising route for sustainable energy storage. However, conventional water electrolysis faces several challenges, such as large thermodynamic potential gaps and sluggish oxygen evolution kinetics, which lead to high electricity consumption and limitations in H storage and transportation. A promising approach to overcoming these hurdles is hybrid water electrolysis, which integrates alternative, thermodynamically favorable reactions at the anode to enhance efficiency.

Selective Toluene Oxidation Using Sulfur-Doped Polymeric Carbon Nitride Photocatalysts.

Selective traditional oxidation of toluene to high-value products like benzyl alcohol, benzaldehyde, and benzoic acid faces significant challenges due to high dissociation energy requirements, harsh reaction conditions, and complex product distributions. While photocatalysis using O as an oxidant offers a green alternative, developing efficient and durable photocatalysts for selective oxidation in both batch and flow systems remains challenging. Here, sulfur-doped polymeric carbon nitride (S-CN) is demonstrated as a versatile photocatalyst for selective toluene oxidation, applicable in both powder form and as binder-free panels across various reactor configurations and solvents.

Catalyst-assisted growth of CsPbBr perovskite nanowires.

Halide perovskites (HPs), particularly at the nanoscale, attract attention due to their unique optical properties compared to other semiconductors. They exhibit bright emission, defect tolerance, and a broad tunable band gap. The ability to directly transport charge carriers along the HPs nanowires (NWs) has led to the development of methods for their synthesis.

Supramolecular interaction of a molecular catalyst with a polymeric carbon nitride photoanode enhances photoelectrochemical activity and stability at neutral pH.

Polymeric carbon nitride (CN) emerged as an alternative, metal-free photoanode material for water-splitting photoelectrochemical cells (PECs). However, the performance of CN photoanodes is limited due to the slow charge separation and water oxidation kinetics due to poor interaction with water oxidation catalysts (WOCs). Moreover, operation under benign, neutral pH conditions is rarely reported.

Supercapattery-Diode: Using Layered Double Hydroxide Nanosheets for Unidirectional Energy Storage.

The supercapacitor-diode (CAPode) is a device that integrates the functionality of an ionic diode with that of a conventional supercapacitor. The unique combination of energy storage and rectification properties in CAPodes is relevant for iontronics, alternate current rectifiers, logic operations, grid stabilization, and even biomedical applications. Here, we propose a novel aqueous-phase supercapattery-diode with excellent energy storage [total specific capacity () = 162 C g, energy density = 34 W h kg at 1.

NC Meets CN: Porous Photoanodes with Polymeric Carbon Nitride/ZnSe Nanocrystal Heterojunctions for Photoelectrochemical Applications.

The utilization of photoelectrochemical cells (PEC) for converting solar energy into fuels (e.g., hydrogen) is a promising method for sustainable energy generation.

Enhancing the Activity of a Carbon Nitride Photocatalyst by Constructing a Triazine-Heptazine Homojunction.

Establishing homojunctions at the molecular level between different but physicochemically similar phases belonging to the same family of materials is an effective approach to promoting the photocatalytic activity of polymeric carbon nitride (CN) materials. Here, we prepared a CN material with a uniform distribution of homojunctions by combining two synthetic strategies: supramolecular assemblies as the precursor and molten salt as the medium. We designed porous CN rods with triazine-heptazine homojunctions (THCNs) using a melem supramolecular aggregate (Me) and melamine as the precursors and a KCl/LiBr salt mixture as the liquid reaction medium.

Ligand Isomerization Driven Electrocatalytic Switching.

The prevailing view about molecular catalysts is that the central metal ion is responsible for the reaction mechanism and selectivity, whereas the ligands mainly affect the reaction kinetics. Here, we question this paradigm and show that ligands have a dramatic influence on the selectivity of the product. We show how even a seemingly small change in ligand isomerization sharply alters the selectivity of the well-researched oxygen reduction reaction (ORR) Co phthalocyanine catalyst from an indirect 2e to a direct 4e pathway.

Unconventional Synthesis of Metal (Ni, Co, Ag) Antimony Alloy Particles.

Bimetallic alloy materials attract interest owing to their properties and stability compared to pure metals, especially alloys with nanoscale dimensions. Metal antimony (MSb) alloys, specifically NiSb, are widely used for charge storage applications due to their high stability. Most synthetic approaches to form these materials require drastic conditions (e.

Boron and Sodium Doping of Polymeric Carbon Nitride Photoanodes for Photoelectrochemical Water Splitting.

Polymeric carbon nitride is a promising photoanode material for water-splitting and organic transformation-based photochemical cells. Despite achieving significant progress in performance, these materials still exhibit low photoactivity compared to inorganic photoanodic materials because of a moderate visible light response, poor charge separation, and slow oxidation kinetics. Here, the synthesis of a sodium- and boron-doped carbon nitride layer with excellent activity as a photoanode in a water-splitting photoelectrochemical cell is reported.

The Implications of Coupling an Electron Transfer Mediated Oxidation with a Proton Coupled Electron Transfer Reduction in Hybrid Water Electrolysis.

Invited for this month's cover are the groups of Menny Shalom at the Ben-Gurion University of the Negev, Israel and Dr. Biswajit Mondal at Indian Institute of Technology Gandhinagar, India. The image shows the connection between two half-cells: an electron transfer-mediated [(2,2,6,6-tetramethyl-1-piperidin-1-yl)oxyl] (TEMPO)-catalyzed benzylamine oxidation at the anode and a proton-coupled electron transfer at the cathode for hydrogen generation.

Developing extended visible light responsive polymeric carbon nitrides for photocatalytic and photoelectrocatalytic applications.

Polymeric carbon nitride (CN) has emerged as an attractive material for photocatalysis and photoelectronic devices. However, the synthesis of porous CNs with controlled structural and optical properties remains a challenge, and processable CN precursors are still highly sought after for fabricating homogenous CN layers strongly bound to a given substrate. Here, we report a general method to synthesize highly dispersed porous CN materials that show excellent photocatalytic activity for the hydrogen evolution reaction and good performance as photoanodes in photoelectrochemical cells (PEC): first, supramolecular assemblies of melem and melamine in ethylene glycol and water are prepared using a hydrothermal process.

Polymeric carbon nitride as a platform for photoelectrochemical water-splitting cells.

Polymeric carbon nitride (CN) materials are promising low-cost photocatalysts that exhibit a combination of chemical and physical properties suitable for converting light into redox activity on their surface. In this perspective, we describe our experience with this family of materials as light absorbers that serve as an anode in photoelectrochemical cells toward water-splitting. We describe some of the CN deposition techniques and procedures established in our lab.

The Implications of Coupling an Electron Transfer Mediated Oxidation with a Proton Coupled Electron Transfer Reduction in Hybrid Water Electrolysis.

Electrolysis of water is a sustainable route to produce clean hydrogen. Full water-splitting requires a high applied potential, in part because of the pH-dependency of the H and O evolution reactions (HER and OER), which are proton-coupled electron transfer (PCET) reactions. Therefore, the minimum required potential will not change at different pHs.

Photoelectrochemical alcohols oxidation over polymeric carbon nitride photoanodes with simultaneous H production.

The photoelectrochemical oxidation of organic molecules into valuable chemicals is a promising technology, but its development is hampered by the poor stability of photoanodic materials in aqueous solutions, low faradaic efficiency, low product selectivity, and a narrow working pH range. Here, we demonstrate the synthesis of value-added aldehydes and carboxylic acids with clean hydrogen (H) production in water using a photoelectrochemical cell based solely on polymeric carbon nitride (CN) as the photoanode. Isotope labeling measurements and DFT calculations reveal a preferential adsorption of benzyl alcohol and molecular oxygen to the CN layer, enabling fast proton abstraction and oxygen reduction, which leads to the synthesis of an aldehyde at the first step.

Supramolecular organization of melem for the synthesis of photoactive porous carbon nitride rods.

Intrinsic defects and structural properties are two main factors influencing the photocatalytic performance of carbon nitride (CN) materials. Here, photoactive porous CN rods are fabricated through the thermal condensation of melem-based hexagonal supramolecular assemblies. To overcome the poor solubility of melem, we exfoliate the bulk melem using hydrochloric acid.

Dynamics of the nanocrystal structure and composition in growth solutions monitored by lab-scale X-ray diffraction.

characterization of nanoparticle (NP) growth has become the state-of-the-art approach for studying their growth mechanisms; there is broad consensus on the reliability and precision of characterization techniques compared to more traditional ones. Nonetheless, most of the currently available methods require the use of sophisticated setups such as synchrotron-based X-ray sources or an environmental liquid transmission electron microscopy (TEM) cell, which are expensive and not readily accessible. Herein, we suggest a new approach to study NP growth mechanisms: using a commercially available heating chamber for time-resolved X-ray diffraction (TR-XRD) measurements of NP growth in solution.

Formation of Copper Oxide Nanotextures on Porous Calcium Carbonate Templates for Water Treatment.

The necessity of providing clean water sources increases the demand to develop catalytic systems for water treatment. Good pollutants adsorbers are a key ingredient, and CuO is one of the candidate materials for this task. Among the different approaches for CuO synthesis, precipitation out of aqueous solutions is a leading candidate due to the facile synthesis, high yield, sustainability, and the reported shape control by adjustment of the counter anions.

Direct growth of uniform carbon nitride layers with extended optical absorption towards efficient water-splitting photoanodes.

A general synthesis of carbon nitride (CN) films with extended optical absorption, excellent charge separation under illumination, and outstanding performance as a photoanode in water-splitting photoelectrochemical cells is reported. To this end, we introduced a universal method to rapidly grow CN monomers directly from a hot saturated solution on various substrates. Upon calcination, a highly uniform carbon nitride layer with tuned structural and photophysical properties and in intimate contact with the substrate is obtained.

Highly Efficient Polymeric Carbon Nitride Photoanode with Excellent Electron Diffusion Length and Hole Extraction Properties.

Polymeric carbon nitride (CN) has emerged as a promising semiconductor in photoanodes for photoelectrochemical cells (PECs) owing to its suitable electronic structure, tunable band gap, high stability, and low price. However, the poor electron diffusion within the CN layer and hole extraction to the solution still limit its applicability in PECs. Here, we report the fabrication of a CN photoanode with excellent electron diffusion length and remarkable hole extraction properties by careful design of its electronic interfaces.

Metal/semiconductor interfaces in nanoscale objects: synthesis, emerging properties and applications of hybrid nanostructures.

Hybrid nanostructures, composed of multi-component crystals of various shapes, sizes and compositions are much sought-after functional materials. Pairing the ability to tune each material separately and controllably combine two (or more) domains with defined spatial orientation results in new properties. In this review, we discuss the various synthetic mechanisms for the formation of hybrid nanostructures of various complexities containing at least one metal/semiconductor interface, with a focus on colloidal chemistry.

Coordination-Directed Growth of Transition-Metal-Crystalline-Carbon Composites with Controllable Metal Composition.

Transition-metal-carbon (CTM) composites show ample activity in many catalytic reactions. However, control of composition, distribution, and properties is challenging. Now, a straightforward path for the synthesis of transition-metal nanoparticles engulfed in crystalline carbon is presented with excellent control over the metal composition, amount, ratio, and catalytic properties.

Freestanding Hierarchical Carbon Nitride/Carbon-Paper Electrode as a Photoelectrocatalyst for Water Splitting and Dye Degradation.

Freestanding electrodes composed of 2D materials are highly attractive for many applications such as batteries, membranes, actuators, optical devices, and other energy-related devices owing to their low price, unique structure, high specific surface area, and excellent mechanical and electrical properties. Here, we report the facile large-scale fabrication of freestanding hierarchical carbon nitride/carbon electrodes (CN/C) by the in situ crystallization of CN precursors on conductive carbon paper, followed by thermal annealing. The resulting CN exhibits a vertically aligned morphology with a homogeneous layer distribution, improved crystallinity, and excellent contact with the carbon paper.