{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T14:03:32Z","timestamp":1785420212703,"version":"3.56.0"},"reference-count":40,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2026,6,20]],"date-time":"2026-06-20T00:00:00Z","timestamp":1781913600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004772","name":"Natural Science Foundation of Ningxia","doi-asserted-by":"publisher","award":["2023AAC03275"],"award-info":[{"award-number":["2023AAC03275"]}],"id":[{"id":"10.13039\/501100004772","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Fundamental Research Funds for the Central Universities, North Minzu University","award":["2025BG199"],"award-info":[{"award-number":["2025BG199"]}]},{"name":"Fundamental Research Funds for the Central Universities, North Minzu University","award":["2024XYZDX01"],"award-info":[{"award-number":["2024XYZDX01"]}]},{"award":["2025BG199"],"award-info":[{"award-number":["2025BG199"]}],"id":[{"id":"https:\/\/ror.org\/05xjevr11","id-type":"ROR","asserted-by":"publisher"}]},{"award":["2024XYZDX01"],"award-info":[{"award-number":["2024XYZDX01"]}],"id":[{"id":"https:\/\/ror.org\/05xjevr11","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Ningxia New Solid Electronic Materials and Devices Research and Development Innovation Team","award":["2020CXTDLX12"],"award-info":[{"award-number":["2020CXTDLX12"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>High-sensitivity detection of formaldehyde is critically important for environmental protection and public health. Zinc oxide (ZnO) is a widely used core material for chemiresistive gas sensors; however, its conventional low-index facets suffer from a limited number of active sites, creating a bottleneck for further sensitivity enhancement. To overcome this limitation, this study pioneers the application of the highly reactive ZnO [202\u00af1] high-index polar surface for formaldehyde detection. By leveraging its unique stepped atomic configuration and unprecedented density of coordination-unsaturated active sites, we systematically investigate the formaldehyde adsorption behavior and the underlying sensing mechanism using first-principles calculations based on density functional theory (DFT). The pristine ZnO [202\u00af1] surface exhibits intrinsic metallic character. At a coverage of 1 monolayer (ML), the most stable G1 configuration achieves an adsorption energy of \u22121.54 eV per CH2O molecule. Within a 2 \u00d7 1 supercell, formaldehyde adopts both associative and dissociative adsorption modes. At a lower coverage, formaldehyde forms a stable bidentate structure through dual C\u2013O and Zn\u2013O bonding interactions. Electronic structure analysis reveals significant orbital hybridization and interfacial charge redistribution upon adsorption. Notably, associative adsorption opens a bandgap of 0.04 eV at the Fermi level, inducing a metal-to-semiconductor transition. In contrast, dissociative adsorption results in pronounced n-type doping, thereby elucidating the microscopic origin of the resistivity decrease observed in ZnO-based sensors. Overall, this work highlights the structural advantages of high-index facets and demonstrates for the first time the superior formaldehyde adsorption capability of the ZnO [202\u00af1] facet, providing robust theoretical guidance for the rational design of next-generation, high-performance gas-sensing materials.<\/jats:p>","DOI":"10.3390\/ma19122661","type":"journal-article","created":{"date-parts":[[2026,6,23]],"date-time":"2026-06-23T08:19:52Z","timestamp":1782202792000},"page":"2661","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A First-Principles Study of Formaldehyde Adsorption on the Surface of ZnO [202\u00af1] High Index Polar Facet"],"prefix":"10.3390","volume":"19","author":[{"given":"Chao","family":"Ma","sequence":"first","affiliation":[{"name":"School of Electrical and Information Engineering, North Minzu University, Yinchuan 750021, China"},{"name":"Institute of Semiconductor Crystals and Ceramic Materials, Helanshan Laboratory, Yinchuan 750021, China"},{"name":"Key Laboratory of Physics and Photoelectric Information Functional Materials, North Minzu University, Yinchuan 750021, China"},{"name":"Microelectronics and Solid-State Electronics Device Research Center, North Minzu University, Yinchuan 750021, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingze","family":"Yao","sequence":"additional","affiliation":[{"name":"School of Electrical and Information Engineering, North Minzu University, Yinchuan 750021, China"},{"name":"Key Laboratory of Physics and Photoelectric Information Functional Materials, North Minzu University, Yinchuan 750021, China"},{"name":"Microelectronics and Solid-State Electronics Device Research Center, North Minzu University, Yinchuan 750021, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuefeng","family":"Xiao","sequence":"additional","affiliation":[{"name":"School of Electrical and Information Engineering, North Minzu University, Yinchuan 750021, China"},{"name":"Key Laboratory of Physics and Photoelectric Information Functional Materials, North Minzu University, Yinchuan 750021, China"},{"name":"Microelectronics and Solid-State Electronics Device Research Center, North Minzu University, Yinchuan 750021, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yujie","family":"He","sequence":"additional","affiliation":[{"name":"School of Electrical and Information Engineering, North Minzu University, Yinchuan 750021, China"},{"name":"Key Laboratory of Physics and Photoelectric Information Functional Materials, North Minzu University, Yinchuan 750021, China"},{"name":"Microelectronics and Solid-State Electronics Device Research Center, North Minzu University, Yinchuan 750021, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hao","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Electrical and Information Engineering, North Minzu University, Yinchuan 750021, China"},{"name":"Key Laboratory of Physics and Photoelectric Information Functional Materials, North Minzu University, Yinchuan 750021, China"},{"name":"Microelectronics and Solid-State Electronics Device Research Center, North Minzu University, Yinchuan 750021, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"122059","DOI":"10.1016\/j.envres.2025.122059","article-title":"Graft\u2212growth of Cobalt\u2212based Prussian Blue Analogs on Bamboo for Indoor Formaldehyde Removal","volume":"282","author":"Zhu","year":"2025","journal-title":"Environ. 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