Pub Date : 2023-06-01DOI: 10.1063/1674-0068/cjcp2304042
Xinlei Chen, Guanjun Wang, Weixing Li
The characterization of the structures of molecular clusters, which serve as building blocks for bulk substances, provides crucial insight into the interactions between constituent units. Chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy, combined with state-of-the-art quantum chemical calculations, is a powerful tool for characterizing the structures of molecular clusters, as the rotational spectra are directly related to the mass distribution of a molecule or cluster. However, determining the structures of large or complex clusters from experimental rotational spectra remains challenging due to their structural flexibility. Ab initio and density functional theory calculations for searching their stable structures could be significantly time-consuming and method-dependent. To address these challenges, we have developed an approach that relies on the experimental rotational constants to search for potential molecular structures without quantum chemical optimization. Our approach involves creating an initial set of conformers through either a semi-empirical sampling program or the quasi-Monte Carlo method. After-ward, the trust region reflective algorithm is utilized for structure fitting. This procedure enables us to quickly generate potential conformers and gain access to precise structural information. We apply our fitting program to water hexamer and benzaldehyde-water clusters, and the resulting topological structures align extremely well with the experimental results.
{"title":"A fitting program for structural determination of molecular clusters from rotational spectroscopy","authors":"Xinlei Chen, Guanjun Wang, Weixing Li","doi":"10.1063/1674-0068/cjcp2304042","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2304042","url":null,"abstract":"The characterization of the structures of molecular clusters, which serve as building blocks for bulk substances, provides crucial insight into the interactions between constituent units. Chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy, combined with state-of-the-art quantum chemical calculations, is a powerful tool for characterizing the structures of molecular clusters, as the rotational spectra are directly related to the mass distribution of a molecule or cluster. However, determining the structures of large or complex clusters from experimental rotational spectra remains challenging due to their structural flexibility. Ab initio and density functional theory calculations for searching their stable structures could be significantly time-consuming and method-dependent. To address these challenges, we have developed an approach that relies on the experimental rotational constants to search for potential molecular structures without quantum chemical optimization. Our approach involves creating an initial set of conformers through either a semi-empirical sampling program or the quasi-Monte Carlo method. After-ward, the trust region reflective algorithm is utilized for structure fitting. This procedure enables us to quickly generate potential conformers and gain access to precise structural information. We apply our fitting program to water hexamer and benzaldehyde-water clusters, and the resulting topological structures align extremely well with the experimental results.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49271842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1063/1674-0068/cjcp2205093
Xiaojun Wang, Ni Lu, Yuan C. Fu, Ch. Lu, Meili Guan, Kunhua Wang, Hao Yu
The 5-hydroxymethylfurfural (5-HMF) acts as an important chemical intermediate to bridge the biomass resources and industrial applications, which shows the potential for green development. However, the performance of biomass materials conversion to 5-HMF is still limited in the green solvent. Herein, an effective approach is reported to prepare the highly efficient solid acid catalysts, NbOx/WOy-ZrO2, to improve fructose conversion. It is found that the introduction of Nb results in the generation of the niobium oxides, which improves acid sites and tunes the ratios of Brønsted acid and Lewis acid on the surface of the WOy-ZrO2 support. With the acidity improvement and increasing acid sites of the NbOx/WOy-ZrO2, the highest fructose conversion is 99% in water. Meanwhile, the 5-HMF yield and the selectivity are also as high as 50.1% and 50.7% under the reaction temperature of 180 °C for a short reaction time of 30 min. The proposed NbOx/WOy-ZrO2 catalyst strategy will not only open a new way for designing the solid acid catalysts to achieve high performance of the 5-HMF in the water, but also promote the green production of biomass and sustainable development in the future.
{"title":"Improved surface acidity of niobium doped tungstated-zirconia solid acid catalyst over production of 5-hydroxymethylfurfural","authors":"Xiaojun Wang, Ni Lu, Yuan C. Fu, Ch. Lu, Meili Guan, Kunhua Wang, Hao Yu","doi":"10.1063/1674-0068/cjcp2205093","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2205093","url":null,"abstract":"The 5-hydroxymethylfurfural (5-HMF) acts as an important chemical intermediate to bridge the biomass resources and industrial applications, which shows the potential for green development. However, the performance of biomass materials conversion to 5-HMF is still limited in the green solvent. Herein, an effective approach is reported to prepare the highly efficient solid acid catalysts, NbOx/WOy-ZrO2, to improve fructose conversion. It is found that the introduction of Nb results in the generation of the niobium oxides, which improves acid sites and tunes the ratios of Brønsted acid and Lewis acid on the surface of the WOy-ZrO2 support. With the acidity improvement and increasing acid sites of the NbOx/WOy-ZrO2, the highest fructose conversion is 99% in water. Meanwhile, the 5-HMF yield and the selectivity are also as high as 50.1% and 50.7% under the reaction temperature of 180 °C for a short reaction time of 30 min. The proposed NbOx/WOy-ZrO2 catalyst strategy will not only open a new way for designing the solid acid catalysts to achieve high performance of the 5-HMF in the water, but also promote the green production of biomass and sustainable development in the future.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46154589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1063/1674-0068/cjcp2304041
Z. Luan, Yanlin Fu, Yuxin Tan, Yaling Wang, An-wen Liu, Tao Wang, Xiaoguo Zhou, Bina Fu, Dong H. Zhang, Daofu Yuan, Xingan Wang, Xueming Yang
We study the photodissociation dynamics of the hydrogen sulfide cations (H2S+) using the time-sliced velocity map ion imaging (VMI) technique and high-accuracy calculations. High-resolution ion images of the S+(4S) products were measured at four photolysis wavelengths of 325.158, 325.200, 325.243, 325.307 nm, which correspond to the excitation to the A2A1(0,13,0) K=1 state of H2S+. Rotational state-resolved total kinetic energy releases and angular distributions have been derived as a function of the photolysis wavelengths. Notably, photolysis wavelength dependent product rotational state and anisotropy parameter distributions have been clearly observed. Full-dimensional potential energy surface characterization suggests that nonadiabatic coupling between A2A1 and B2B2 states at C2v configurations, as well as relaxation of the symmetry to Cs in the conical intersection region between the two states, plays a key role in the photodissociation process.
{"title":"Photodissociation dynamics of H2S+ near 325 nm","authors":"Z. Luan, Yanlin Fu, Yuxin Tan, Yaling Wang, An-wen Liu, Tao Wang, Xiaoguo Zhou, Bina Fu, Dong H. Zhang, Daofu Yuan, Xingan Wang, Xueming Yang","doi":"10.1063/1674-0068/cjcp2304041","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2304041","url":null,"abstract":"We study the photodissociation dynamics of the hydrogen sulfide cations (H2S+) using the time-sliced velocity map ion imaging (VMI) technique and high-accuracy calculations. High-resolution ion images of the S+(4S) products were measured at four photolysis wavelengths of 325.158, 325.200, 325.243, 325.307 nm, which correspond to the excitation to the A2A1(0,13,0) K=1 state of H2S+. Rotational state-resolved total kinetic energy releases and angular distributions have been derived as a function of the photolysis wavelengths. Notably, photolysis wavelength dependent product rotational state and anisotropy parameter distributions have been clearly observed. Full-dimensional potential energy surface characterization suggests that nonadiabatic coupling between A2A1 and B2B2 states at C2v configurations, as well as relaxation of the symmetry to Cs in the conical intersection region between the two states, plays a key role in the photodissociation process.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49005833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1063/1674-0068/cjcp2104071
Antony Minja, Taotao Wang, Hongyun Cao, Pingwu Du
Herein, we present the decoration of NiFeCoAlOOH nanoparticles onto titanium doped nanoporous hematite (Ti-PH) utilizing a simple electroless ligand-controlled oxidation method for photoelectrochemical water splitting. Owing to the improved oxygen evolution reaction kinetics and reduced charge transfer resistance, the resulting Ti-PH/NiFeCoAlOOH photoanode presents an excellent photocurrent density of 2.46 mA/cm2 at 1.23 V vs. RHE and good stability compared to Ti-PH or bare hematite. Furthermore, the onset potential of the photocurrent density is shifted cathodically by ∼60 mV with reference to the titanium doped nanoporous hematite. This work offers a promising method for designing high-performance, stable, and inexpensive catalysts for photoelectrochemical applications.
{"title":"Titanium doped nanoporous hematite photoanode modified with NiFeCoAlOOH nanoparticles for efficient photoelectrochemical water splitting","authors":"Antony Minja, Taotao Wang, Hongyun Cao, Pingwu Du","doi":"10.1063/1674-0068/cjcp2104071","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2104071","url":null,"abstract":"Herein, we present the decoration of NiFeCoAlOOH nanoparticles onto titanium doped nanoporous hematite (Ti-PH) utilizing a simple electroless ligand-controlled oxidation method for photoelectrochemical water splitting. Owing to the improved oxygen evolution reaction kinetics and reduced charge transfer resistance, the resulting Ti-PH/NiFeCoAlOOH photoanode presents an excellent photocurrent density of 2.46 mA/cm2 at 1.23 V vs. RHE and good stability compared to Ti-PH or bare hematite. Furthermore, the onset potential of the photocurrent density is shifted cathodically by ∼60 mV with reference to the titanium doped nanoporous hematite. This work offers a promising method for designing high-performance, stable, and inexpensive catalysts for photoelectrochemical applications.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135219501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1063/1674-0068/cjcp2106103
Kangkang He, Fei Hu, Chaoshi Chen, M. Atif, Yanmei Wang
Mixed polymer brushes coating based on poly (2-methyl-2-oxazoline)/ poly(4-vinyl pyridine) (PMOXA/P4VP) was prepared by simultaneously grafting amine-terminated PMOXA and thiolterminated P4VP onto poly(dopamine) (PDA)-modified substrates in this work. The coatings were characterized by X-ray photoelectron spectroscopy, ellipsometry, zeta potential measurements, and the static water contact angle tests. The results indicated that it is feasible to control the components of the coating by adjusting the feed ratio of PMOXA to P4VP. Moreover, the zeta potential and the water contact angle of mixed brushes modified surfaces could be tuned by changing the environmental pH value and surface compositions. Finally, fluorescein isothiocyanate-labelled pepsin assay and surface plasmon resonance were performed to investigate the responsive adsorption/desorption of pepsin by PMOXA/P4VP mixed brushes. The results showed that by adjusting the fraction of PMOXA or P4VP, the PMOXA/P4VP mixed brushes coated surfaces could adsorb a high amount of pepsin at pH=3, and achieve a desorption efficiency of over 92% at pH=7.
{"title":"Polydopamine anchored poly(2-methyl-2-oxazoline)/poly(4-vinyl pyridine) mixed brushes with switchable properties for pepsin adsorption","authors":"Kangkang He, Fei Hu, Chaoshi Chen, M. Atif, Yanmei Wang","doi":"10.1063/1674-0068/cjcp2106103","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2106103","url":null,"abstract":"Mixed polymer brushes coating based on poly (2-methyl-2-oxazoline)/ poly(4-vinyl pyridine) (PMOXA/P4VP) was prepared by simultaneously grafting amine-terminated PMOXA and thiolterminated P4VP onto poly(dopamine) (PDA)-modified substrates in this work. The coatings were characterized by X-ray photoelectron spectroscopy, ellipsometry, zeta potential measurements, and the static water contact angle tests. The results indicated that it is feasible to control the components of the coating by adjusting the feed ratio of PMOXA to P4VP. Moreover, the zeta potential and the water contact angle of mixed brushes modified surfaces could be tuned by changing the environmental pH value and surface compositions. Finally, fluorescein isothiocyanate-labelled pepsin assay and surface plasmon resonance were performed to investigate the responsive adsorption/desorption of pepsin by PMOXA/P4VP mixed brushes. The results showed that by adjusting the fraction of PMOXA or P4VP, the PMOXA/P4VP mixed brushes coated surfaces could adsorb a high amount of pepsin at pH=3, and achieve a desorption efficiency of over 92% at pH=7.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58525812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1063/1674-0068/cjcp2106111
yingzhong huo, Ruoxuan Guo, Kexin Lin, Yuejie Ai
The general application of antibiotics has brought a series of negative impacts on human health and the environment, which has aroused widespread public attention to their removal from aqueous systems. In this study, a chitosan (CS)-linked graphene oxide (GO) composite (GO-CS) was synthesized by a modified hummers/solvothermal method. It was separated from the mixed aqueous phase by low-speed centrifugation, thereby endowing the GO with high separation efficiency in water. The adsorption of tetracycline (TC), norfloxacin (NOR), and sulfadiazine (SDZ) by GO-CS were then studied by experimental techniques and theoretical calculations. In batch experiments at 298 K and optimal pH, the adsorption capacities of TC, NOR, and SDZ were 597.77, 388.99, and 136.37 mg/g, respectively, which were far better than those of pristine graphene oxide. The spectra results illustrated that the adsorption process was mainly contributed by the interactions between antibiotics and functional groups (carboxyl, hydroxyl, and amino groups) of GO-CS. Furthermore, density functional theory calculations showed that electrostatic interaction and hydrogen bonds were of vital importance for the uptake of the antibiotics; the former was extremely important for TC adsorption. This research provides theoretical references for the removal of antibiotics by graphene-based composite materials, thus offering their promising application in environmental remediation.
{"title":"Insights into interface mechanism of three typical antibiotics onto the graphene oxide/chitosan composite: Experimental and theoretical investigation","authors":"yingzhong huo, Ruoxuan Guo, Kexin Lin, Yuejie Ai","doi":"10.1063/1674-0068/cjcp2106111","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2106111","url":null,"abstract":"The general application of antibiotics has brought a series of negative impacts on human health and the environment, which has aroused widespread public attention to their removal from aqueous systems. In this study, a chitosan (CS)-linked graphene oxide (GO) composite (GO-CS) was synthesized by a modified hummers/solvothermal method. It was separated from the mixed aqueous phase by low-speed centrifugation, thereby endowing the GO with high separation efficiency in water. The adsorption of tetracycline (TC), norfloxacin (NOR), and sulfadiazine (SDZ) by GO-CS were then studied by experimental techniques and theoretical calculations. In batch experiments at 298 K and optimal pH, the adsorption capacities of TC, NOR, and SDZ were 597.77, 388.99, and 136.37 mg/g, respectively, which were far better than those of pristine graphene oxide. The spectra results illustrated that the adsorption process was mainly contributed by the interactions between antibiotics and functional groups (carboxyl, hydroxyl, and amino groups) of GO-CS. Furthermore, density functional theory calculations showed that electrostatic interaction and hydrogen bonds were of vital importance for the uptake of the antibiotics; the former was extremely important for TC adsorption. This research provides theoretical references for the removal of antibiotics by graphene-based composite materials, thus offering their promising application in environmental remediation.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136186793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding organic photovoltaic (OPV) work principles and the materials’ optoelectronic properties is fundamental for developing novel heterojunction materials with the aim of improving power conversion efficiency (PCE) of organic solar cells. Here, in order to understand the PCE performance (>13%) of OPV device composed of the non-fullerene acceptor fusing naphtho[1,2-b:5,6-b′]dithiophene with two thieno[3,2-b]thiophene (IDCIC) and the polymer donor fluorobenzotriazole (FTAZ), with the aid of extensive quantum chemistry calculations, we investigated the geometries, molecular orbitals, excitations, electrostatic potentials, transferred charges and charge transfer distances of FTAZ, IDCIC and their complexes with face-on configurations, which was constructed as heterojunction interface model. The results indicate that, the prominent OPV performance of FTAZ:IDCIC heterojunction is caused by co-planarity between the donor and acceptor fragments in IDCIC, the the charge transfer (CT) and hybrid excitations of FTAZ and IDCIC, the complementary optical absorptions in visible region, and the large electrostatic potential difference between FTAZ and IDCIC. The electronic structures and excitations of FTAZ/IDCIC complexes suggest that exciton dissociation can fulfill through the decay of local excitation exciton in acceptor by means of hole transfer, which is quite different from the OPVs based on fullerenes acceptor. The rates of exciton dissociation, charge recombination and CT processes, which were evaluated by Marcus theory, support the efficient exciton dissociation that is also responsible for good photovoltaic performance.
{"title":"Theoretical study on organic photovoltaic heterojunction FTAZ/IDCIC","authors":"Bingwang Yang, Cairong Zhang, Yu Wang, Mei-ling Zhang, Zi-Jiang Liu, Youzhi Wu, Hongshan Chen","doi":"10.1063/1674-0068/cjcp2109160","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2109160","url":null,"abstract":"Understanding organic photovoltaic (OPV) work principles and the materials’ optoelectronic properties is fundamental for developing novel heterojunction materials with the aim of improving power conversion efficiency (PCE) of organic solar cells. Here, in order to understand the PCE performance (>13%) of OPV device composed of the non-fullerene acceptor fusing naphtho[1,2-b:5,6-b′]dithiophene with two thieno[3,2-b]thiophene (IDCIC) and the polymer donor fluorobenzotriazole (FTAZ), with the aid of extensive quantum chemistry calculations, we investigated the geometries, molecular orbitals, excitations, electrostatic potentials, transferred charges and charge transfer distances of FTAZ, IDCIC and their complexes with face-on configurations, which was constructed as heterojunction interface model. The results indicate that, the prominent OPV performance of FTAZ:IDCIC heterojunction is caused by co-planarity between the donor and acceptor fragments in IDCIC, the the charge transfer (CT) and hybrid excitations of FTAZ and IDCIC, the complementary optical absorptions in visible region, and the large electrostatic potential difference between FTAZ and IDCIC. The electronic structures and excitations of FTAZ/IDCIC complexes suggest that exciton dissociation can fulfill through the decay of local excitation exciton in acceptor by means of hole transfer, which is quite different from the OPVs based on fullerenes acceptor. The rates of exciton dissociation, charge recombination and CT processes, which were evaluated by Marcus theory, support the efficient exciton dissociation that is also responsible for good photovoltaic performance.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44625066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1063/1674-0068/36/02/cabs
{"title":"Chinese Abstracts","authors":"","doi":"10.1063/1674-0068/36/02/cabs","DOIUrl":"https://doi.org/10.1063/1674-0068/36/02/cabs","url":null,"abstract":"","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135573799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1063/1674-0068/cjcp2109153
Peiping Yu, Yu Wu, Hao Yang, Miao Xie, W. Goddard, Tao Cheng
The industrial pollutant NO is a potential threat to the environment and to human health. Thus, selective catalytic reduction of NO into harmless N2, NH3, and/or N2O gas is of great interest. Among many catalysts, metal Pd has been demonstrated to be most efficient for selectivity of reducing NO to N2. However, the reduction mechanism of NO on Pd, especially the route of N−N bond formation, remains unclear, impeding the development of new, improved catalysts. We report here the elementary reaction steps in the reaction pathway of reducing NO to NH3, N2O, and N2, based on density functional theory (DFT)-based quantum mechanics calculations. We show that the formation of N2O proceeds through an Eley-Rideal (E−R) reaction pathway that couples one adsorbed NO* with one non−adsorbed NO from the solvent or gas phase. This reaction requires high NO* surface coverage, leading first to the formation of the trans-(NO)2* intermediate with a low N−N coupling barrier (0.58 eV). Notably, trans-(NO)2* will continue to react with NO in the solvent to form N2O, that has not been reported. With the consumption of NO and the formation of N2O* in the solvent, the Langmuir-Hinshelwood (L-H) mechanism will dominate at this time, and N2O* will be reduced by hydrogenation at a low chemical barrier (0.42 eV) to form N2. In contrast, NH3 is completely formed by the L-H reaction, which has a higher chemical barrier (0.87 eV). Our predicted E-R reaction has not previously been reported, but it explains some existing experimental observations. In addition, we examine how catalyst activity might be improved by doping a single metal atom (M) at the NO* adsorption site to form M/Pd and show its influence on the barrier for forming the N−N bond to provide control over the product distribution.
{"title":"Atomistic mechanisms for catalytic transformations of NO to NH3, N2O, and N2 by Pd","authors":"Peiping Yu, Yu Wu, Hao Yang, Miao Xie, W. Goddard, Tao Cheng","doi":"10.1063/1674-0068/cjcp2109153","DOIUrl":"https://doi.org/10.1063/1674-0068/cjcp2109153","url":null,"abstract":"The industrial pollutant NO is a potential threat to the environment and to human health. Thus, selective catalytic reduction of NO into harmless N2, NH3, and/or N2O gas is of great interest. Among many catalysts, metal Pd has been demonstrated to be most efficient for selectivity of reducing NO to N2. However, the reduction mechanism of NO on Pd, especially the route of N−N bond formation, remains unclear, impeding the development of new, improved catalysts. We report here the elementary reaction steps in the reaction pathway of reducing NO to NH3, N2O, and N2, based on density functional theory (DFT)-based quantum mechanics calculations. We show that the formation of N2O proceeds through an Eley-Rideal (E−R) reaction pathway that couples one adsorbed NO* with one non−adsorbed NO from the solvent or gas phase. This reaction requires high NO* surface coverage, leading first to the formation of the trans-(NO)2* intermediate with a low N−N coupling barrier (0.58 eV). Notably, trans-(NO)2* will continue to react with NO in the solvent to form N2O, that has not been reported. With the consumption of NO and the formation of N2O* in the solvent, the Langmuir-Hinshelwood (L-H) mechanism will dominate at this time, and N2O* will be reduced by hydrogenation at a low chemical barrier (0.42 eV) to form N2. In contrast, NH3 is completely formed by the L-H reaction, which has a higher chemical barrier (0.87 eV). Our predicted E-R reaction has not previously been reported, but it explains some existing experimental observations. In addition, we examine how catalyst activity might be improved by doping a single metal atom (M) at the NO* adsorption site to form M/Pd and show its influence on the barrier for forming the N−N bond to provide control over the product distribution.","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45027573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1063/1674-0068/36/01/cabs
{"title":"Chinese Abstracts","authors":"","doi":"10.1063/1674-0068/36/01/cabs","DOIUrl":"https://doi.org/10.1063/1674-0068/36/01/cabs","url":null,"abstract":"","PeriodicalId":10036,"journal":{"name":"Chinese Journal of Chemical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135096510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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