Michael Volokh

Ben-Gurion University of the Negev | bgu · Department of Chemistry

Hypothesis: Subjecting colloids to electric fields often results in (electrophoretic) deposition on conductive substrates. Dispersing a single-source precursor (SSP) of choice in an appropriate solvent, should allow its deposition on different substrates. The SSP-solvent interaction might play a role in the deposition (e.g., direction, rate, cover...

Graphitic carbon nitride materials (CNs) have emerged as suitable photocatalysts and heterogeneous catalysts for various reactions thanks to their tunable band gap, suitable energy‐band position, high stability under harsh chemical conditions, and low cost. However, the utilization of CN in photoelectrochemical (PEC) and photoelectronic devices is...

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 synth...

Carbon nitride polymers have emerged as a new class of materials for a wide range of applications such as photo- and electro-catalysis, sensors, bioimaging and more due to their chemical, photophysical and catalytic properties as well as their low-price, facile synthesis and high stability under harsh chemical conditions. In this review we begin wi...

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 photoelectrochemic...

The formation of CsPbBr 3 NW via the solution–solid–solid. At elevated temperatures, the ME catalyst undergoes a phase transition, facilitating the diffusion of reactants and the subsequent precipitation of solid CsPbBr 3 nanowires.

Rechargeable alkaline zinc–air batteries (ZAB) hold great promise as a viable, sustainable, and safe alternative energy storage system to the lithium‐ion battery. However, the practical realization of ZABs is limited by their intrinsically low energy trip efficiency, stemming from a large charge and discharge potential gap. This overpotential is at...

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 b...

The utilization of photoelectrochemical cells (PEC) for converting solar energy into fuels (e.g., hydrogen) is a promising method for sustainable energy generation. We demonstrate a strategy to enhance the performance of PEC devices by integrating surface-functionalized zinc selenide (ZnSe) semiconductor nanocrystals (NCs) into porous polymeric car...

Polymeric carbon nitride (CN) has emerged as a promising photoanodic material in water‐splitting photoelectrochemical cells (PEC). However, the current deposition methods of CN layers on substrates usually include a long heating process at 500−550 °C, which might cause sublimation or decomposition of the CN monomers and destruction of the substrate...

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 i...

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 i...

Controlling the properties of a carbon nitride (CN) layer during its in–situ growth on a conductive substrate, including its directionality, morphology, surface area, and defects, is challenging because of the...

Polymeric carbon nitrides (CN) have gained significant interest as photoanodes in photoelectrochemical cells (PEC). A widely researched approach for synthesizing CN films with controlled optical and photoelectrochemical properties relies on using supramolecular assemblies as the precursors for thermal polymerization over a transparent conductive su...

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,...

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...

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 H2 and O2 evolution reactions (HER and OER), which are proton‐coupled electron transfer (PCET) reactions. Therefore, the minimum required potential will not change at different p...

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 sub...

Carbon nitride (CN) materials demonstrate great promise as photocatalysts for various reactions. However, synthesizing a CN with high dispersibility in water, large specific surface area, ordered morphology, and high catalytic activity remains a challenge. Melem (2,5,8‐triamino‐tri‐s‐triazine), has emerged as a monomer for the synthesis of CN mater...

Photocatalysis using polymeric carbon nitride (CN) materials is a constantly evolving field, where the variation of synthetic procedures allows the constant improvement of activity by tackling the intrinsic limitations of these materials (optical absorbance, specific surface area, charge migration, etc.). Amongst the possible photocatalytic reactio...

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 a...

The photocatalytic activity of polymeric carbon nitride (CN) is strongly tied to its surface area, morphology, optical, and electronic properties. Herein, a straightforward approach to adjusting the electronic properties and morphology of CN materials by fine tuning their carbon content while preserving their high surface area is proposed. To do so...

In situ 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 in situ characterization techniques compared to more traditional ex situ ones. Nonetheless, most of the currently available methods require the use of sophis...

Nickel phosphides are highly attractive low-cost (electro)catalysts, thanks to their unique electronic structure, versatile phase diagram, and chemical stability. Herein, we describe a single-step, simple, and scalable synthesis of nickel...

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...

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 faci...

We design a new supramolecular assembly family as reactants to synthesize highly-photoactive porous polymeric carbon nitride (CN), based on a melem-constructed honeycomb, coupled with the insertion of small triazine analogs. The inclusion of small molecules into the melem-based hexameric rings leads to a highly porous CN with controlled electronic,...

Electrocatalytic oxidative upgrading of organic molecules is a promising alternative process to water oxidation for clean hydrogen production. Yet, its underlying mechanism is still not fully understood, and suitable low‐cost electrocatalysts with good product selectivity and activity are still sought after. Here, an active NiFeOx‐based catalyst is...

The challenge in synthesizing hydrogen peroxide from O2 and H2O is to balance several concurrent reactions. Now, selective H2O2 production is achieved on a noble-metal-free photocatalyst based on carbon-nitride-supported antimony single atoms.

Carbon nitrides (CN) have emerged as promising photoanode materials for water‐splitting photoelectrochemical cells (PECs). However, their poor charge separation and transfer properties, together with slow water‐oxidation kinetics, have resulted in low PEC activity and instability, which strongly impede their further development. In this work, these...

Polymeric carbon nitride (CN) has emerged as a promising semiconductor in photoelectrochemical devices, thanks to its unique electronic and catalytic properties, low price, stability in various chemical environments, and benign nature. Decent progress in the deposition and growth of CN layers on substrates has been achieved using several deposition...

The electrochemical properties of spinel ferrites have been studied since the 1970s after the pioneering discovery of water electrolysis by using TiO2 as the photoanode in a photoelectrochemical cell. Several approaches have been developed to fabricate ferrites of different sizes and shapes but most of these methods suffer from several disadvantage...

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...

A simple, straightforward growth method of polymeric carbon nitride (CN) layers on a conductive substrate, with excellent photoelectrochemical activity owing to the formation of a type-II heterojunction by combining two distinct chemical growth methods is reported. The first layer consists of CN prepared from the calcination of a melem-melamine (Me...

The large-scale fabrication of polymeric carbon nitride (CN) films with tunable thickness, composition and photoelectrochemical properties is reported. To do so, we deposited supramolecular complexes as seeding layers prior to a thermal deposition of melamine vapor. The seeding layer is successfully formed by employing electrophoretic deposition of...

Polymeric carbon nitride (CN) has emerged as a promising semiconductor in photoanodes for photoelectrochemical cells (PEC) owing to its suitable electronic structure, tunable band gap, high stability, and low price. However, the poor electrons diffusion within the CN layer and hole extraction to the solution still limit its applicability in PECs. H...

A high-temperature solid-state synthesis is a widespread tool for the construction of metal-free materials, owing to its simplicity and scalability. However, no method is currently available for the synthesis of metal-free materials, which enables control over the atomic ratio and spatial organization of several heteroatoms. Here we report a genera...

Two-dimensional CdS-based hybrid nanostructures are intriguing materials with an application prospect in different fields such as sensing (i. e., photoresistors) and solar energy harvesting (photocatalysis, photovoltaics, and so forth). We report herein a colloidal synthetic path for interfacing metal and semiconductor with 2D CdS nanoplates. Selec...

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,...

Transition metals‐carbon (CTM) composites show ample activity in many catalytic reactions. However, a synthesis which allows control over their final composition, distribution and properties is still considered as a great challenge. Here, we report a new, straightforward path for the synthesis of transition‐metal nanoparticles engulfed in crystalli...

A general and straightforward synthesis of a series of solution‐processable carbon nitride polymers is described with excellent and tunable optical and electronic properties. The high dispersibility of carbon nitride polymers functionalized with polycyclic aromatic hydrocarbons (PAH‐CNs) in common solvents permits their facile processing into thin...

Free-standing 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 as well as excellent mechanical and electrical properties. Here, we report the facile large-sc...

Electrocatalytic water-splitting is considered as a highly promising technology for the sustainable production of hydrogen. Currently, the commercial distribution of such devices is limited by the high price of noble metals (e.g. Pt) electrocatalysts, which still show the best activity toward the hydrogen evolution reaction (HER). Cheaper, non-nobl...

Low‐cost and high‐efficiency electrocatalysts for the hydrogen evolution reaction (HER) are a key constituent of a low‐carbon industrial economy based on intermittent energy production in the near future. A facile wet‐chemistry strategy has been developed for the synthesis of a porous Ru layer deposited onto Ni foam (NF) as a competitive candidate...

Herein we report a facile method to grow an ordered carbon nitride (CN) layer with improved charge separation and transfer properties under illumination. We first prepared viscous and uniform supramolecular pastes solely consisting of various ratios of melamine and graphene oxide (GO) in ethylene glycol. Adding GO to CN precursor solutions was foun...

A microorganism template approach has been explored for the fabrication of various well-defined three-dimensional (3D) structures. However, most of these templates suffer from small size (few μm), difficulty to remove the template, or low surface area, which affect their potential use in different applications or makes industrial scale-up difficult...

A wide range of nanoparticle properties can be tuned by changing their surface characteristics, especially when dealing with ultrathin nanomaterials. Surface modification with transition‐metal ions may affect a variety of the nanoparticles' properties including the surface charge, the electronic structure, and the electrical and optical characteris...

Graphitic carbon nitride materials (CNs) have emerged as suitable photo‐ and heterogeneous‐ catalysts for various reactions thanks to their tunable band gap, suitable energy‐band position, high stability under harsh chemical conditions, and low cost. However, the utilization of CN in photoelectrochemical (PEC) and photoelectronic devices is still a...

The insertion of heteroatoms with different electronegativity into carbon materials can tune their chemical, electronic, and optical properties. However, in the traditional solid‐state synthesis, it is challenging to control the monomers' reactivity and therefore the amount and position of heteroatoms in the final materials. Here we report a simple...

Polymeric carbon nitride (CN) has emerged as a promising semiconductor for energy‐related applications. However, its utilization in photo‐electrochemical cells is still very limited owing to poor electron–hole separation efficiency, short electron diffusion length, and low absorption coefficient. Here the synthesis of a highly porous carbon nitride...

2D carbon and nitrogen based semiconductors (CN) have attracted widespread attention for their possible use as low‐cost and environmentally friendly materials for various applications. However, their limited solution‐dispersibility and the difficulty in preparing exfoliated sheets with tunable photophysical properties restrain their exploitation in...

Given their unique properties, tremendous progress is realized in the use of nanostructured materials for various applications. However, their incorporation and fabrication into prototypic devices remain challenging due to their limited ability to form hierarchical 3D structures through the use of large scale, low cost, and facile processes. Herein...