Silver nanoparticle-doped beidellite: Eco-friendly catalyst for efficient hazardous organic pollutants reduction

Design and synthesis of a new coordination polymer of zinc (II): Crystal structure and evaluation for its adsorption studies in removing perilous organic dye pollutants in aqueous medium

Review for "Review on polyaniline-based nanocomposite heterogeneous catalysts for catalytic reduction of hazardous water pollutants"

Catalytic activity and stability of Pd/Co catalysts in simultaneous selective catalytic reduction of NOx with methane and oxidation of o-dichlorobenzene

This study unveils the synthesis and application of Cu-doped ZnO nanorods (NRS) as an efficient catalyst for the photocatalytic reduction of hazardous hexavalent chromium (Cr6+) in water. Synthesized via a simplified co-precipitation method, the NRS demonstrated enhanced performance, achieving an 89.35% Cr6+ reduction efficiency under optimal conditions. The catalyst’s performance was significantly augmented in the presence of hydrogen peroxide (H2O2) and revealed a first-order kinetic model. Radical trapping experiments highlighted the pivotal role of hydroxyl radicals in the photocatalytic process. A comparative analysis of the NRS with LED/ZnO and undoped ZnO underscores the superior efficiency of the Cu-doped variant. Moreover, the applicability of this system was validated in real water and wastewater matrices containing Cr6+, indicating its promising potential for industrial and environmental applications. An in vivo bioassay using Daphnia magna further confirmed the reduced toxicity post-treatment, underscoring the environmental friendliness of this innovative approach. The findings present Cu-doped ZnO nanorods as a promising, effective, and eco-friendly catalyst for the remediation of Cr6+ contaminated water, marking a significant stride towards sustainable and efficient water treatment solutions.

Ruthenium nanoparticles stabilised by an amine‐modified Ordered Mesoporous Silica Immobilized Ionic Liquid (OMSIIL) are efficient catalysts for the partial reduction of nitrobenzene to hydrazobenzene with 100 % selectivity as well as the complete reduction to aniline. High selectivity for the partial reduction of nitrobenzene to hydrazobenzene was obtained when the reaction was conducted in ethanol with 0.5 mol% catalyst and NaBH4 as the hydrogen donor whereas aniline was obtained as the sole product in water when dimethylamine borane (DMAB) was used as the hydrogen donor. Interestingly, while a range of electron poor nitroarenes were reduced to the corresponding hydrazoarene with high selectivities and good conversions, nitroarenes substituted with electron donating groups resulted in complete reduction to the aniline. Composition‐time profiles suggest that reductions conducted in ethanol with sodium borohydride occur via the condensation pathway while those conducted in water using dimethylamine borane as the hydrogen source may well go via the direct pathway. This is the first example of the selective reduction of nitrobenzene to hydrazobenzene using a ruthenium nanoparticle‐based catalyst and the initial TOF of 320 mol nitrobenzene converted mol Ru−1 h−1 for the partial reduction of nitrobenzene to hydrazobenzene is markedly higher than previous literature reports. A study of the catalyst performance as a function of the surface modification revealed that each component has a direct and dramatic effect on the efficacy as RuNPs stabilised by COK‐12 modified with imidazolium‐based ionic liquid and a primary amine gave the highest conversion while selective removal of either component or replacement of the primary amine with a tertiary amine resulted in a marked reduction in efficiency.

A coupled photocatalytic system has been constructed by integrating CdS quantum dots as a light-absorber and polyoxometalate-supported [Re(CO)3]+ (POM-Re) catalysts, which exhibited efficient activity towards photoreduction of CO2 to HCOOH. Mechanistic studies revealed that the favorable migration of photogenerated electrons endows Sb2W20Re2 with efficient photocatalytic CO2 reduction activity.

Enhanced photocatalytic CO2 reduction to CH4 on oxygen vacancy-rich NiCo2O4 with surface pits: Synthesis, DFT calculations, and mechanistic insights

The relevance of aryl amines as raw materials for a variety of applications has prompted substantial research into developing highly efficient protocols for hazardous nitroarenes reduction. To that end, a new sustainable and heterogeneous palladium nanocatalyst was fabricated by immobilization of PdNPs on the new magntic support composed of carboxymethyl-imidazolium ionic liquid-grafted chitosan Schiff base and magnetic graphene oxide (CMICSB-MGO) nanocomposites. The spectral, thermal, and microscopic analyses results revealed the successful formation of the magnetic support and nanocatalyst. The activity of the new nanocatalyst (CMICSB-MGO-Pd) in the catalytic reduction of hazardous nitroarenes to convert them into valuable aminoarenes was studied. The findings demonstrated that the new nanocatalyst has excellent catalytic activity, superior recoverability, as well as outstanding reusability under very mild reaction conditions. Moreover, this nanocatalyst can be recycled up to 8 catalytic runs, without significant loss in its efficacy or Pd leaching. Thus, the new magnetic support and nanocatalyst are more eco-friendly and sustainable choices for large-scale use and could pave the way for developing other metal-based catalysts for versatile applications in the future.

Bi2O3/Al2O3 catalysts for the selective reduction of NO with hydrocarbons in lean conditions

Encapsulation Fe-Nx combined with Co@C to construct efficient oxygen reduction catalysts with bimetallic sites and the application of Zn-air batteries

The rational design of active and durable reversible oxygen electrocatalysts plays a key role in renewable energy conversion and storage. Here we developed copper and cobalt-based oxide/iron hydroxide hybrid nanowire arrays (CuCoOx/FeOOH) via a three-step growth–annealing–conversion approach. These hybrid nanowires offer a large surface area for electrocatalytic sites, abundant pores for fast electrolyte access, efficient charge transfer, and strong coupling between CuCoOx and FeOOH components. Attributed to these features, the CuCoOx/FeOOH nanowires exhibit excellent bifunctional oxygen evolution reaction and oxygen reduction reaction activities, including low overpotentials, high current densities, and outstanding stabilities. Using the CuCoOx/FeOOH electrocatalyst as the oxygen electrode, a rechargeable zinc–air battery was fabricated to exhibit a small charge–discharge overpotential (0.75 V at 10 mA·cm–2) and a long-term cycling stability (150 cycles), thus suggesting new bifunctional electrocatalysts for energy conversion and storage applications.

Landfill leachate generation from a landfill site is one of the main problems for both developed and developing countries around the world. Leachates liberated from the site contain various organic, inorganic, heavy metals, and sometimes hazardous chemical and organic pollutants, which are the origin of the deterioration of air and water quality in its vicinity. The present attempt was performed to assess seasonal variation of the leachate quality, and also determine three sub-indices of leachate which are LPIorg, LPIin, and LPIhm, and the overall LPI of operational, uncontrolled landfills in South Delhi by using leachate pollution index (LPI). Around twenty-five (25) parameters were analyzed during pre-monsoon, monsoon, and post-monsoon seasons from the collected leachate samples. Out of twenty-five pollutants, COD, BOD, NH4-N, EC, and TDS were found beyond the set standard limit in all seasons. Other pollutants like TKN, TSS, TCB, and Cl were also found in high concentrations. Arsenic (As) concentration was found beyond permissible during post-monsoon. The concentration of lead (Pd) in the pre and post-monsoon season was observed beyond the standard limit. Sub-LPI indices in the pre-monsoon season were observed as LPIorg 82.0, LPIin 40.8, and LPIhm 6.9, and likewise, Sub-LPI in monsoon season were LPIorg 81.4, LPIin 25.5, and LPIhm 5.2 and Sub-LPI post-monsoon season was calculated as LPIorg 90.5, LPIin 30.2 and LPI hm 6.2. Almost in all the seasons, LPIorg i.e. organic pollutants was dominated then followed by LPIin, and LPIhm. The overall LPI value of the study area during the pre-monsoon, monsoon and post-monsoon was 32.5, 28.2 and 32.0, respectively. It was observed that overall LPI (calculated) was maximum during pre-monsoon followed by post-monsoon and monsoon. LPI value was beyond the standard limit, except for LPI hm, which was below the standards. It was recommended that more waste-to-energy plants and decentralized waste segregation units need to be set up, to avoid direct dumping of all mixed waste in the landfill sites.

Cobalt with porous carbon architecture: Towards of 4-nitrophenol degradation and reduction

Enhanced electrochemical O2 reduction to H2O2 through resilient hybrid catalysts modified with DMSO in electro-Fenton

Nanostructured heterogeneous catalysts for electrochemical reduction of CO2