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Present work puts forward an efficient strategy to degrade one of the persistent antibiotic contaminants, ciprofloxacin (CIP). Hybrid advanced oxidation process (HAOP) is tailored with a synergy effect between photocatalysis and photo-Fenton catalysis on zinc ferrite-titania heterostructured composite (ZFO-TiO

This review predominantly focuses on the progress of a variety of cobalt-based nitride materials, especially pertaining to their photo(electro)catalytic applications in solar energy conversion.

The rational design of novel transition metal nitride-based piezo-catalysts provides a novel strategy for developing non-carbon energy sources to alleviate global warming.

Significant efforts have been directed towards the use of transition metal nitrides as electrocatalysts for hydrogen evolution reaction (HER). Molybdenum nitride, despite its promise for scalable production, suffers from the bottleneck of poor catalytic activity. Furthermore the kinetics of water dissociation process ought to be improved for enhancing its potential. Here, we report a facile method for the incorporation of trace amount of Pd nanoparticle into Mo3N2 nanobelts (0.75Pd/Mo3N2,) for enhanced HER in both acidic and alkaline solutions. When employed for HER, the 0.75 wt%Pd/Mo3N2 nanobelt delivers excellent catalytic activity with overpotentials of 45 and65 mV in 0.5 M H2SO4 and 1 M KOH at a current density of 10 mA cm-2. As-prepared 0.75 wt%Pd/Mo3N2 displays a smaller Tafel slope and offers substantial stability in both acidic and alkaline media under the same operating conditions. The improved performance of the as-prepared 0.75 wt%Pd/Mo3N2 points to fast charge transfer, higher electrical conductivity and synergistic effects between Pd and Mo. This work displays a direct method for reducing the use and cost associated with use of platinum-group metals while also delivering superior HER catalytic performance.

Development of stable and efficient non-noble metal-based catalysts for oxygen evolution reactions (OERs) continues to pose a significant challenge owing to sluggish reaction kinetics (since it commonly involves four electron processes and O–O bond formation). Transition metal nitrides and oxynitrides are of particular interest in energy conversion and storage technologies due to its unique properties like metallic conductivity, wettability, durability, and chemical stability. However, chromium oxynitride is less explored as a catalyst for OER. In this work, we report chromium oxynitride (CrON) nanoparticles with spherical morphology, which are tested for electrocatalytic OER activity for the first time. The study is also conducted with its corresponding nitride (chromium nitride (CrN)) and oxide phase (chromium oxide (Cr2O3)) to benchmark the OER performance of the oxynitride. CrON nanoparticles show superior OER electrocatalytic properties over its corresponding nitride (CrN) and oxide (Cr2O3) material. CrON nanoparticles exhibit an overpotential of 409 mV at a current density of 10 mA cm−2, with a Tafel slope of 157 mV dec−1, and offers good stability for over 12h in alkaline medium. These values are lower than that of CrN (overpotential of 446 mV at 10 mA cm−2, and Tafel slope of 162 mV dec−1), and Cr2O3 (overpotential 477 mV and Tafel slope 210 mV dec−1).

As a consequence of rapid industrialization throughout the world, various environmental pollutants have begun to accumulate in water, air, and soil. This endangers the ecological environment of the earth, and environmental remediation has become an immediate priority. Among various environmental remediation techniques, piezocatalytic techniques, which uniquely take advantage of the piezoelectric effect, have attracted much attention. Piezoelectric effects allow pollutant degradation directly, while also enhancing photocatalysis by reducing the recombination of photogenerated carriers. In this Review, we provide a comprehensive summary of recent developments in piezocatalytic techniques for environmental remediation. The origin of the piezoelectric effect as well as classification of piezoelectric materials and their application in environmental remediation are systematically summarized. We also analyze the potential underlying mechanisms. Finally, urgent problems and the future development of piezocatalytic techniques are discussed.

Dataset for the study published inhttps://www.sciencedirect.com/science/article/abs/pii/S0378775322009569

From an engineering standpoint, specific capacity and cyclic stability may be considered the two most critical performance-related features for supercapacitor electrodes. The prediction of these two parameters is hence crucial for evaluating the prospect of a given material for a supercapacitor-electrode application. However, this prediction is highly non-trivial using existing atomistic approaches. As a solution, a combinatorial approach of value and grade prediction machine-learning models are used to predict the performance of a novel material (cerium oxynitride) for supercapacitor application. The model predicts the material to have a specific capacity of ~26.6 mAh g−1 and capacity retention of >90% for a particular material (morphology, composition, surface area) and operational (current density, applied potential window etc.) properties; which can be viably achieved via urea glass method. The experimental results (~26 mAh g−1 and ~100% capacity retention) considerably validate the predictive approach presented here. This article is the first instance wherein cerium oxynitride has been predicted and reported as a supercapacitor electrode. This makes the prediction and the validation made in this study of contemporary relevance.

Hydrogen production from wastewater system has the potential to add a new dimension to the energy economy. Urine is an abundant waste and contains about 90–96% of water. While there have been efforts to generate electricity from urine (using microbial fuel cells), direct hydrogen production from urine using any technique is less explored. We report human and cow urine pretreatment with simultaneous hydrogen production using a simple redox reaction. This is achieved via in situ formation of aluminium nanoparticles in urine through reduction of aluminum salt using sodium borohydride; the key novelty of the process is the use of Al salt/NaBH4. The in situ prepared aluminium nanoparticles instantly react with urine to produce hydrogen. The volume of hydrogen produced is observed to be sensitive to pH, amount of Al salt, and ageing (storage time of urine). Interestingly, ageing does not impact the kinetics of initial hydrolysis in cow urine as much as it affects in the case of human urine. Fresh urine is found to be better in both the cases. Total carbon, total organic carbon, total nitrogen and total phosphorus removal efficiencies are found to be a maximum of 69.93%, 71.88%, 64.16% and 50.9% respectively for human urine; these values are 67.8%, 70.1%, 61.3% and 48.9% for cow urine at pH 3.

Heavy metals (Hg, Cd, Pb, etc.) are micro-pollutants and result in water contamination. Significant bio-concentration of heavy metal like Hg can lead to fatal disease such as Minamata. Given this context, heavy metal removal from wastewater is essential before discharge. The wastewater treatment process requires considerable amount of energy which is being met by the conventional carbon-based fuels. This contributes to the global carbon dioxide emission, and hence global warming. Therefore, if clean energy sourcing is enabled during the treatment of the wastewater; it would offer obvious advantages. If the energy production is ‘clean’ and achieved via the process itself, it would serve two outcomes: (a) meeting the energy demand for wastewater treatment, and (b) getting rid of the need for external ‘carbon-based’ energy. Recently a few research articles have reported simultaneous clean energy production from wastewater during its treatment. Thus, the energy demand of the wastewater treatment process can be potentially met with the clean energy produced during the process. In this review, we will discuss mercury-contaminated wastewater treatment with simultaneous hydrogen production. We will provide a brief overview of waste-to-wealth approaches currently prevailing in water economy, recent mercury removal processes, and discuss future possibilities of self-sustained Hg-contaminated wastewater treatment.

Laser-assisted doping of intrinsic silicon carbide (SiC) films deposited on Si (100) substrates by pulsed laser deposition (PLD) method and its influence on simultaneous annealing of the thin film is studied. PLD grown intrinsic SiC films are transformed to p-type SiC and n-type SiC, using laser-assisted doping in aqueous aluminum chloride and phosphoric solutions, respectively. Simultaneous doping and annealing of the SiC film are observed during laser-assisted doping. By precisely positioning the selectively doped region, lateral p–n diodes are formed on the SiC films without using any mask. Electric characteristics confirmed the formation of a lateral p–n diode structure. Numerical analysis of temperature distribution along the depth of the SiC films explains the mechanism of simultaneous doping and annealing during the laser treatment.

We report structural and optical properties of Dy3+ doped Na0.5Bi0.5TiO3 (NBT), labeled as Dyx:NBT (x = 0.00–0.14). X-ray and neutron diffraction results of Dyx:NBT (x = 0.06 and 0.08) show the occupation of Dy3+ in both Bi and Ti-sites. Such behavior of a dopant ion occupying both in A and B-sites of ABO3 is called “amphotericity”. In conjunction with the above, Raman spectra show additional breathing vibrational (A1g) modes in the region of 700–900 cm−1. It confirms the asymmetry in TiO6 polyhedra and random distribution of Dy3+ and Ti4+ ions. Photoluminescence (PL) spectra show blue (484 nm; 4F9/2→6H15/2; magnetic dipole (MD) transition) and yellow (575 nm; 4F9/2→6H13/2; electric dipole (ED) transition) emissions. The asymmetric ratio (ED/MD) of emission transitions further confirms the amphoteric distribution of Dy3+ ions. Amphotericity and site-dependent luminescence variation show a strong correlation in structure-property relationships.

Active cooling-based atmospheric water generators, despite their growing demand, continue to be energy intensive and offer poor collection efficiencies (energy consumption per liter of water produc...

Semiconducting metal oxides (SMOXs) are used widely for gas sensors. However, the effect of ambient humidity on the baseline and sensitivity of the chemiresistors is still a largely unsolved problem, reducing sensor accuracy and causing complications for sensor calibrations. Presented here is a general strategy to overcome water-sensitivity issues by coating SMOXs with a hydrophobic polymer separated by a metal–organic framework (MOF) layer that preserves the SMOX surface and serves a gas-selective function. Sensor devices using these nanoparticles display near-constant responses even when humidity is varied across a wide range [0–90 % relative humidity (RH)]. Furthermore, the sensor delivers notable performance below 20 % RH whereas other water-resistance strategies typically fail. Selectivity enhancement and humidity-independent sensitivity are concomitantly achieved using this approach. The reported tandem coating strategy is expected to be relevant for a wide range of SMOXs, leading to a new generation of gas sensors with excellent humidity-resistant performance.

Silicon carbide (SiC) thin films were grown by pulsed laser deposition (PLD) on Si (1 0 0) substrates at a substrate temperature of 800 °C. Besides, laser annealing was performed on the post deposited intrinsic amorphous SiC films using Nd3+:YAG 355 nm laser in the Ar environment. The laser-annealed samples showed the crystalline characteristics. Crystalline characteristics of PLD grown, laser annealed samples were identified by X-ray diffraction (XRD), Raman analysis. Numerical analysis performed on SiC/Si interface to investigate the temperature distribution, to understand the mechanism of laser assisted annealing.

Oxygen electroreduction (ORR) via a two-electron pathway is a promising alternative for hydrogen peroxide (H2O2) synthesis in small-scale applications. In this work, nitrogen and sulfur co-doped carbon coated zinc sulfide nanoparticles (ZnS@C) are synthesized using facile high-temperature annealing. In an alkaline electrolyte, the presence of ZnS suppresses the reduction of H2O2 during the ORR and contributes to high H2O2 selectivity (∼90%) over a wide potential range (0.40-0.80 V). Continuous generation of H2O2 is in turn achieved at an outstanding rate of 1.485 mol gcat.-1 h-1 with a faradaic efficiency of 93.7%.

Conversion of Cr(VI) to Cr(III) in mitigating pollution of water bodies is of significant importance to public health due to the fact that Cr(VI) is known to be a potent carcinogen, while Cr(III) is relatively low in toxicity. Photocatalytic approaches are considered as important means to achieve this reduction. Here, TiO2/SnS2 core-shell nanostructures have been produced using a single-step hydrothermal method and its photocatalytic activity is tested for the reduction of aqueous Cr(VI). The structural and optical properties of the as-synthesized products are characterized by XRD, HRTEM, Raman, FTIR, XPS and DRS techniques. The present work reveals that by calcining the core-shell nanoparticles in Ar atmosphere a defective Ti3O5 phase is formed as the core with low band gap, and hence, offers improved light absorption in the visible range. However, its photoactivity was found to be lower than that of the core-shell nanoparticles annealed in oxidizing atmosphere. The observed lower photoreduction was due to the presence of midgap states which acted as recombination centres and hence, reduced the photocatalytic activity.

Efficient electrocatalysts for water splitting are essential for viable generation of highly purified hydrogen. Hence there is a need to develop robust catalysts to eliminate barriers associated with sluggish kinetics associated with both anodic oxygen and cathodic hydrogen evolution reactions. Herein, we report a two-step nanocasting-solid phase phosphorization approach to generate ordered mesoporous triphasic phosphides CoP@Cu2P-Cu3P. We show that it is a highly efficient bifunctional electrocatalyst useful for overall water splitting. The mesoporous triphasic CoP@Cu2P-Cu3P only requires a low overpotential of 255 mV and 188 mV to achieve 10 mA cm−2for oxygen and hydrogen evolution reactions, respectively. The combination of mesoporous pores (∼5.6 nm) with very thin walls (∼3.7 nm) and conductive networks in triphasic CoP@Cu2P-Cu3P enable rapid rate of electron transfer and mass transfer. In addition, when CoP@Cu2P-Cu3P is used to fabricate symmetric electrodes, the high surface area mesoporous structure and synergetic effects between phases together contribute to a low cell voltage of 1.54 V to drive a current density 10 mA cm−2. This performance is superior to noble-metal-based Pt/C-IrO2/C. This work provides a new approach for the facile design and application of multiphase phosphides as highly active bifunctional and stable electrocatalysts for water-alkali electrolyzers.

A dual-phase transition metal nitride (TMN) based Co

Atomically dispersed Co-N-C is a promising material for H2O2 selective electrosynthesis via a two-electron oxygen reduction reaction. However, the performance of typical Co-N-C materials with routine Co-N4 active center is insufficient and needs to be improved further. This can be done by fine-tuning its atomic coordination configuration. Here, a single-atom electrocatalyst (Co/NC) is reported that comprises a specifically penta-coordinated Co-N-C configuration (O-Co-N2C2) with Co center coordinated by two nitrogen atoms, two carbon atoms, and one oxygen atom. Using a combination of theoretical predictions and experiments, it is confirmed that the unique atomic structure slightly increases the charge state of the cobalt center. This optimizes the adsorption energy towards *OOH intermediate, and therefore favors the two-electron ORR relevant for H2O2 electrosynthesis. In neutral solution, the as-synthesized Co/NC exhibits a selectivity of over 90% over a potential ranging from 0.36 to 0.8 V, with a turnover frequency value of 11.48 s−1; thus outperforming the state-of-the-art carbon-based catalysts.

Visible-light-driven hydrogen production is a promising pathway to realize efficient solar energy utilization. Here, Nd3+ incorporated ZnIn2S4 (Nd-ZIS) was synthesized via facile one step hydrothermal method. Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS) confirm the successful incorporation of Nd3+ in ZnIn2S4. Optical studies reveal the reduction of effective bandgap from 2.7 eV to 2.54 eV upon incorporation of Nd3+ with improved charge carrier life time of 3.12 ns. Electronic properties of ZIS and Nd-ZIS were investigated from first principle calculations. An attempt to improve photocatalytic activity of ZIS by modification with Nd3+ ions resulted in degradation of organic pollutant up to 98% under natural sunlight and decrease in life time of trap states up to a nominal value of 200 ms (as evident from photoelectrochemical measurements). The mechanism behind enhancement of photocatalytic activity of ZIS post Nd3+ integration has been proposed. Nd-ZIS was also utilized for water splitting activity exhibiting a considerable H2 generation ∼3415 μmol g−1. To the best of our knowledge, activity of Nd3+ incorporated ZIS has been explored for the first time in present work. It is believed that an in-depth understanding of photoactivity of ZIS would be significantly important for designing materials with desired photocatalytic performance in future.

Advance applications like water splitting system and rechargeable metal-air battery are highly dependent on efficient electrocatalyst for the oxygen evolution reaction (OER). Heterostructured materials, with a high active surface area and electron effect, accomplish enhanced catalytic performance. Here, a nitride-sulfide composite (FeNi

The oxygen evolution reaction (OER) is key to renewable energy technologies such as water electrolysis and metal-air batteries. However, the multiple steps associated with proton-coupled electron transfer result in sluggish OER kinetics and catalysts are required. Here we demonstrate that a novel nitride, Ni2 Mo3 N, is a highly active OER catalyst that outperforms the benchmark material RuO2 . Ni2 Mo3 N exhibits a current density of 10 mA cm-2 at a nominal overpotential of 270 mV in 0.1 m KOH with outstanding catalytic cyclability and durability. Structural characterization and computational studies reveal that the excellent activity stems from the formation of a surface-oxide-rich activation layer (SOAL). Secondary Mo atoms on the surface act as electron pumps that stabilize oxygen-containing species and facilitate the continuity of the reactions. This discovery will stimulate the further development of ternary nitrides with oxide surface layers as efficient OER catalysts for electrochemical energy devices.