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New catalysts for liquid phase nitrate reduction wererecentlysynthesized using multiwalled carbon nanotubes as a support. The mostpromising catalyst (1%Pd–1%Cu/CNT) was used in this kineticstudy. The catalyst experimentally showed high selectivity to nitrogen,between 80 and 89%. A mechanistic model was applied to experimentaldata to show that the reason for high selectivity is due to the enhancedmass transfer near the catalyst surface promoted by the use of a structuredsupport. The experimental selectivity is close to the maximum selectivitypredicted for this catalytic system at the best operating conditionsand in the absence of any mass transfer limitations. [ABSTRACT FROM AUTHOR]

Glucose is a key intermediate in cellulose photoreforming for H 2 production. This work presents a mechanistic investigation of glucose photoreforming over TiO 2 and Pt/m-TiO 2 catalysts. Analysis of the intermediates formed in the process confirmed the α-scission mechanism of glucose oxidation forming arabinose (C n-1 sugar) and formic acid in the initial oxidation step. The selectivity to sugar products and formic acid differed over Pt/TiO 2 and TiO 2 , with Pt/TiO 2 showing the lower selectivity to formic acid due to enhanced adsorption/conversion of formic acid over Pt/TiO 2 . In situ ATR-IR spectroscopy of glucose photoreforming showed the presence of molecular formic acid and formate on the surface of both catalysts at low glucose conversions, suggesting that formic acid oxidation could dominate surface reactions in glucose photoreforming. Further in situ ATR-IR of formic acid photoreforming showed Pt-TiO 2 interfacial sites to be key for formic acid oxidation as TiO 2 was unable to convert adsorbed formic acid/formate. Isotopic studies of the photoreforming of formic acid in D 2 O (with different concentrations) showed that the source of the protons (to form H 2 at Pt sites) was determined by the relative surface coverage of adsorbed water and formic acid., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Catalytic wastewater treatment has rarely been applied to treat high-ionic-strength wastewater (HISWW) as it contains large amounts of catalyst poisons (e.g., Cl - ). This work investigates the catalytic wet oxidation (CWO) of phenol over a MnCeO x catalyst in the presence of high NaCl concentrations where the combination of MnCeO x and NaCl promoted the CWO of phenol. Specifically, in the presence of NaCl at a concentration of 200 g L -1 and MnCeO x at a concentration of 1.0 g L -1 , phenol (initially 1.0 g L -1 ) and total organic carbon (TOC) conversions were ∼98 and 85%, respectively, after a 24 h reaction. Conversely, under the same reaction conditions without NaCl, the catalytic system only achieved phenol and TOC conversions of ∼41 and 27%, respectively. In situ Attenuated Total Reflection infrared spectroscopy identified the nature of the strongly adsorbed carbon deposits with quinone/acid species found on Ce sites and phenolate species on Mn sites in the single oxides and on MnCeO x . The presence of high concentrations of NaCl reduced the carbon deposition over the catalyst, promoting surface oxidation of the hydrocarbon and reoxidation of the catalyst, resulting in enhanced mineralization. Moreover, the used MnCeO x catalyst in the salt water system was efficiently regenerated via a salt water wash under the reaction conditions, showing the great potential of MnCeO x in practical HISWW treatment., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Photoreforming of cellulose is a promising route for sustainable H 2 production. Herein, ball-milling (BM, with varied treatment times of 0.5-24 h) was employed to pretreat microcrystalline cellulose (MCC) to improve its activity in photoreforming over a Pt/TiO 2 catalyst. It was found that BM treatment reduced the particle size, crystallinity index ( CrI ), and degree of polymerization ( DP ) of MCC significantly, as well as produced amorphous celluloses (with >2 h treatment time). Amorphous cellulose water-induced recrystallization to cellulose II (as evidenced by X-ray diffraction (XRD) and solid-state NMR analysis) was observed in aqueous media. Findings of the work showed that the BM treatment was a simple and effective pretreatment strategy to improve photoreforming of MCC for H 2 production, mainly due to the decreased particle size and, specifically in aqueous media, the formation of the cellulose II phase from the recrystallization of amorphous cellulose, the extent of which correlates well with the activity in photoreforming., Competing Interests: The authors declare no competing financial interest., (© 2022 American Chemical Society.)

Developing high-performance catalysts toward the Fenton reaction is important for environmental protection and sustainable development, yet it is still challenging. The high-spin states of first-row transition metal atoms with tetrahedral coordination provide a flexible electronic environment to activate the catalyst and elevate its catalytic activity. As a type of material with adjustable structures, metal-organic frameworks (MOFs) are excellent candidate catalysts as they can accurately regulate the coordination configurations of metal ions. In this paper, we investigate and summarize the direct formation of bimetallic carboxylate Li/Co-MOFs with tetrahedral coordination metal centers in a mixed H 2 O/polar organic solvent system. The induction of Li(I) ions is manifested in the generation of hydroxides during the dissociation of the Co(II) solvation structure to trigger the tetrahedral coordination behavior of Co(II). These Li/Co-MOFs containing high-spin Co(II) centers can serve as highly efficient Fenton-like catalysts for organics. This study provides a promising strategy for rational design of MOF-based catalysts with high-spin metal centers for application in environment governance.

A quantitative method for assessment of defects in metal-organic framework (MOF) is presented based on isotherms calculated using Grand Canonical Monte Carlo (GCMC) simulations. Defects in MOF structures generated during the synthesis and sample preparation can lead to large variations in experimentally measured adsorption isotherms but are difficult to quantify. We use as a case study CO2 adsorption on Cu3(BTC)2 MOF (BTC = benzene-1,3,5-tricarboxylic acid) to show that different samples reported in the literature have various proportions of principal pores blocked or side pores blocked, resulting in isotherms with different capacity and affinity toward CO2. The approach presented is easily generalized to other materials, showing that simulation results combined with experimentally measured gas adsorption isotherms can be used to quantitatively identify key defective features of the material.