AB INITIO INVESTIGATION OF GAS ADSORPTION ON Γ-GRAPHYNE: ELECTRONIC STRUCTURE MODULATION AND POTENTIAL APPLICATIONS IN SENSING

Regina Lelis de Sousa; Sara da Costa Barbosa

Título do Trabalho

Autores

Regina Lelis de Sousa
Sara da Costa Barbosa

Modalidade

Pôster - resumo

Área temática

Sensores e biossensores

Data de Publicação

27/05/2026

País da Publicação

Brasil

Idioma da Publicação

pt-BR

Página do Trabalho

https://www.even3.com.br/anais/workshop-do-ineo-2026/1462705-ab-initio-investigation-of-gas-adsorption-on--graphyne--electronic-structure-modulation-and-potential-applicati

ISBN

978-65-272-2467-9

Palavras-Chave

Gamma-graphyne, gas sensing, density functional theory, van der Waals corrections, Chlorine (Cl2)

Resumo

Two-dimensional (2D) carbon allotropes have emerged as highly promising platforms for next-generation gas-sensing technologies, primarily due to their large surface-to-volume ratios, tunable electronic properties, and structural versatility [1,2]. Gamma-Graphyne, characterized by a mixed sp²/sp hybridization arising from the periodic insertion of acetylenic linkages (–C=C–) into a graphene-like hexagonal lattice, possesses an intrinsic semiconducting band gap (~0.5 eV) combined with high carrier mobility, rendering it particularly suitable for chemiresistive sensing applications [3,4]. We report a comprehensive first-principles investigation of the adsorption of four environmentally and industrially relevant molecules — CH4, CO, CS2, and Cl2 — on a pristine Gamma-graphyne monolayer, employing Density Functional Theory (DFT) with van der Waals dispersion corrections (GGA-PBE+vdW) as implemented in PWSCF [5]. Adsorption was systematically evaluated at four high-symmetry sites (H1: center of the sp² hexagonal ring, H2: center of the sp–sp² cavity, T1: sp² carbon, T2: sp carbon of the acetylenic bond), considering multiple molecular orientations and initial molecule–surface separations of approximately 3.0 Å and 1.5 Å. All systems were fully relaxed without geometric constraints, and electronic properties were characterized through band-gap analysis and projected density of states (PDOS) calculations. The results establish a well-defined sensitivity hierarchy: Cl2 » CS2 ˜ CO » CH4. CH4 exhibits exclusively weak physisorption (E_ad = -0.25 to -0.27 eV) with negligible band-gap modulation (~2%), indicating that effective methane detection would require surface functionalization or heteroatom doping. CS2 and CO physisorb preferentially at ring sites (H1/H2) with moderate adsorption energies (-0.26 to -0.33 eV) and band-gap variations below 2%, chemisorbed configurations at T1/T2 sites yield significant band-gap reductions (~11–13%) but are thermodynamically prohibited (E_ad > 0). In contrast, Cl2 undergoes thermodynamically favorable dissociative chemisorption at the T2 site (E_ad = -0.42 eV), with formation of covalent C–Cl bonds (d = 1.78 Å) and substantial elongation of the Cl–Cl distance from 2.01 Å to 2.88 Å. The Cl2_near_T1 configuration induces the largest electronic perturbation observed in this study, reducing the band gap from 0.50 eV to 0.37 eV (-27.18%) — a modulation exceeding those reported for graphene (<5%) and transition metal dichalcogenides (10–15%) [6]. PDOS analysis confirms that Cl2 is the sole adsorbate contributing directly to frontier states (valence band maximum and conduction band minimum), corroborating its exceptional sensing potential. These findings position pristine Gamma-graphyne as a selective and intrinsically sensitive platform for Cl2 detection, with direct applicability to industrial safety monitoring, water treatment facilities, and environmental sensing systems. Acknowledgements: INEO Project (FAPESP – grant nº 2025/27044-5 and CNPq – grant nº 408449/2024-1). References: [1] Novoselov et al., Science 306, 666 (2004). [2] Varghese et al., Sens. Actuators B 218, 160 (2015). [3] Li et al., Carbon 136, 248 (2018). [4] Puigdollers et al., Carbon 96, 879 (2016). [5] Giannozzi et al., J. Phys.: Condens. Matter 21, 395502 (2009). [6] Late et al., ACS Nano 7, 4879 (2013).

Título do Evento: Workshop do INEO 2026
Cidade do Evento: Nazaré Paulista
Título dos Anais do Evento: Anais do Workshop do INEO 2026
Nome da Editora: Even3
Meio de Divulgação: Meio Digital

Como citar

SOUSA, Regina Lelis de; BARBOSA, Sara da Costa. AB INITIO INVESTIGATION OF GAS ADSORPTION ON Γ-GRAPHYNE: ELECTRONIC STRUCTURE MODULATION AND POTENTIAL APPLICATIONS IN SENSING.. In: Anais do Workshop do INEO 2026. Anais...Nazaré Paulista(SP) Hotel Estância Atibainha, 2026. Disponível em: https//www.even3.com.br/anais/workshop-do-ineo-2026/1462705-AB-INITIO-INVESTIGATION-OF-GAS-ADSORPTION-ON--GRAPHYNE--ELECTRONIC-STRUCTURE-MODULATION-AND-POTENTIAL-APPLICATI. Acesso em: 10/08/2026