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Novel mechanistic insights into methane activation over Fe and Cu active sites in zeolites: A comparative DFT study using meta-GGA functionals
Mahyuddin M.H.a, Staykov A.b, Saputro A.G.a, Agusta M.K.a, Dipojono H.K.a, Yoshizawa K.a,b
a Research Group of Advanced Functional Materials, Faculty of Industrial Technology, Research Center for Nanoscience and Nanotechnology, Institut Teknologi Bandung, Bandung, 40132, Indonesia
b Institute for Materials Chemistry and Engineering, IRCCS, Kyushu University, Fukuoka, 819-0395, Japan
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© 2020 American Chemical Society.Fe- and Cu-exchanged zeolites are known to oxidize methane directly to methanol at low temperature and have been intensively discussed in recent literature studies including theoretical works based on the density functional theory (DFT). However, there are a number of computational results that are contradictive to each other due to a limitation in accessing accurate methods for realistic models. To address this issue, in this study, we utilize a relatively accurate yet computationally efficient meta-GGA method, including the TPSS, RTPSS, MS0, MS1, MS2, and SCAN functionals, combined with the D2 method of dispersion correction to calculate the homolytic C-H bond cleavage of methane on the periodic structures of [FeO]2+-ZSM-5, [Cu2(μ-O)]2+-ZSM-5, and [Cu3(μ-O)3]2+-MOR zeolites. Besides showing energetics and geometrical comparisons, herein through analysis of projected density of states, we identify [FeIV= O]2+, [CuII2(μ-O)]2+, and [CuII2CuIII(μ-O)2(μ-O·)]2+ as the preferred electronic structures for the corresponding active species. In addition, we discuss in great detail the fundamental difference in the C-H bond cleavage mechanism for each active species to show the high importance of accurately treating the formed Fe-OH bond on the stability of transition (TS) and radical intermediate (RI) states and to clarify the role of the O atom radical character in preserving the stability of the [Cu3(μ-O)3]2+ active species when the TS and RI states are formed. We also show the importance of correctly describing (i) weak interactions involved in the methane adsorption state and (ii) Cu-O-Cu bond strengths involved in the TS and RI states for predicting a reasonable reaction energy trend.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Computational results,Computationally efficient,Dispersion correction,Literature studies,Methane activation,Methane adsorption,Projected density of state,Weak interactions[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text][{‘$’: ‘This work is partially funded by the Ministry of Education and Culture and the Ministry of Research and Technology of the Republic of Indonesia under a grant scheme of World Class University (WCU) program managed by Institut Teknologi Bandung. A.S. and K.Y. acknowledge the KAKENHI grant with grant numbers of JP24109014, JP15K13710, and JP17H03117 from Japan Society for the Promotion of Science (JSPS) and the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), the MEXT Projects of ?World Premier International (WPI) Research Center Initiative?, ?Integrated Research Consortium on Chemical Sciences?, and ?Elements Strategy Initiative to Form Core Research Center?, and the JST-CREST with grant numbers of JPMJCR15P5 and JPMJCR18R2. The computations were performed at the Research Institute for Information Technology (Kyushu University).’}, {‘$’: ‘This work is partially funded by the Ministry of Education and Culture and the Ministry of Research and Technology of the Republic of Indonesia under a grant scheme of World Class University (WCU) program managed by Institut Teknologi Bandung. A.S. and K.Y. acknowledge the KAKENHI grant with grant numbers of JP24109014, JP15K13710, and JP17H03117 from Japan Society for the Promotion of Science (JSPS) and the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), the MEXT Projects of “World Premier International (WPI) Research Center Initiative”, “Integrated Research Consortium on Chemical Sciences”, and “Elements Strategy Initiative to Form Core Research Center”, and the JST-CREST with grant numbers of JPMJCR15P5 and JPMJCR18R2. The computations were performed at the Research Institute for Information Technology (Kyushu University).’}][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1021/acs.jpcc.0c04991[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]