Quantum State–Resolved Studies of Chemisorption Reactions

Walnut shell biochar (WSC) and wood powder biochar (WPC) prepared using the limited oxygen pyrolysis process were used as raw materials, and ZnCl2, KOH, H2SO4, and H3PO4 were used to modify them. The evaluation of the liquid-phase adsorption performance using methylene blue (MB) as a pigment model showed that modified biochar prepared from both biomasses had a mesoporous structure, and the pore size of WSC was larger than that of WPC. However, the alkaline modified was more conducive to the formation of pores in the biomass-modified biochar materials; KOH treatment resulted in the highest modified biochar-specific surface area. The isothermal adsorption of MB by the two biomass pyrolysis charcoals conformed to the Freundlich equation, and the adsorption process conformed to the quasi-second-order kinetic equation, which is mainly physical adsorption. The large number of oxygen-containing functional groups on the particle surface provided more adsorption sites for MB adsorption, which was beneficial to the adsorption reactions. The adsorption effects of woody biomass were obviously higher than that of shell biomass, and the adsorption capacities of the two raw materials’ pyrolysis charcoal were in the order of WPC > WSC. The adsorption effects of different treatment reagents on MB were in the order ZnCl2 > KOH > H3PO4 > H2SO4. The maximum adsorption capacities of the two biomass treatments were 850.9 mg/g for WPC with ZnCl2 treatment and 701.3 mg/g for WSC with KOH treatment.

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“…The formation of shared electrons or transfer of electrons between adsorbates is through selective and monolayer adsorption. 22 , 23 …”

Section: Introductionmentioning

confidence: 99%

Preparation of Acid- and Alkali-Modified Biochar for Removal of Methylene Blue Pigment

et al. 2020

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“…Over the last decades, quantum state-resolved molecular beam scattering from well-defined surfaces has contributed much to our understanding of these dynamics [1][2][3][4][5][6]. Apart from giving direct insight, state-resolved data are used to gauge theoretical models, thereby paving the way toward a predictive understanding of heterogeneous catalysis [7][8][9][10][11]. Experiments that probe the quantum state populations of the scattered products have proven particularly rewarding as the final distributions resolved in internal quantum state, angle, and speed contain a wealth of dynamical information.…”

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confidence: 99%

Vibrational Energy Redistribution in a Gas-Surface Encounter: State-to-State Scattering of CH4 from Ni(111)

et al. 2018

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The fate of vibrational energy in the collision of methane (CH_{4}) in its antisymmetric C-H stretch vibration (ν_{3}) with a Ni(111) surface has been studied in a state-to-state scattering experiment. Laser excitation in the incident molecular beam prepared the J=1 rotational state of ν_{3}, and a bolometer in combination with selective laser excitation detected the scattered methane. The rovibrationally resolved scattering distributions reveal very efficient vibrational energy redistribution from ν_{3} to the symmetric C-H stretch vibration (ν_{1}). The branching ratio ν_{1}/ν_{3} is near 0.4 and insensitive to changes in incident kinetic energy in the range from 100 to 370 meV. State-resolved angular distributions and measurements of the residual Doppler linewidths prove that the scattering is direct. The observed vibrationally inelastic scattering provides direct experimental evidence for surface-induced vibrational energy redistribution.

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“…Their detailed understanding is of relevance in many areas, for example, atmospheric and interstellar chemistry, combustion, and catalysis. [ 1–10 ] The most detailed results, initial state‐selected and fully quantum state‐resolved reaction probabilities and cross sections, can be computed from full‐dimensional quantum dynamics simulations for reactions involving only few atoms. The biggest system treated today is the H + CH 4 →H 2 +CH 3 reaction.…”

Section: Introductionmentioning

confidence: 99%

State‐selective cross sections from ring polymer molecular dynamics

Marjollet

Welsch

2020

Int J of Quantum Chemistry

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Understanding the influence of different forms of energy (eg, translational, vibrational, rotational) on chemical reactions is a key goal and great challenge in physical chemistry. Very recently, we proposed a new approach to obtain state-selective cross sections that approximately include quantum effects such as zero-point energy and tunneling. The method is a combination of the widely used quasiclassical trajectory approach (QCT) and the ring polymer molecular dynamics method and thus is numerically very efficient and easily employed. Here, we present a detailed description of the method and exhaustive tests of its accuracy and applicability. The robustness of the approach is tested, as well as the convergence with the number of beads. The approach is then applied to several prototypical X + H 2 (ν = 0, 1), X = Mu, H, D, F, Cl reactions over a wide range of collision energies. Good agreement with rigorous quantum dynamics simulations is found for most cases. Encouraging improvement over QCT results is found for particular cases, while only a small increase in numerical cost is required.

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Quantum State–Resolved Studies of Chemisorption Reactions

Cited by 79 publications

References 148 publications

Preparation of Acid- and Alkali-Modified Biochar for Removal of Methylene Blue Pigment

Preparation of Acid- and Alkali-Modified Biochar for Removal of Methylene Blue Pigment

Vibrational Energy Redistribution in a Gas-Surface Encounter: State-to-State Scattering of CH4 from Ni(111)

State‐selective cross sections from ring polymer molecular dynamics

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