{"id":584353,"date":"2026-08-14T09:30:14","date_gmt":"2026-08-14T09:30:14","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/584353\/"},"modified":"2026-08-14T09:30:14","modified_gmt":"2026-08-14T09:30:14","slug":"chemists-may-be-misassigning-defects-in-carbon-materials-study-suggests-research","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/584353\/","title":{"rendered":"Chemists may be misassigning defects in carbon materials, study suggests | Research"},"content":{"rendered":"

Certain peaks in the spectra of carbon-based materials can arise from multiple defects, researchers have concluded after computational analysis revealed that non-hexagonal rings, oxygen-containing functional groups and vacancy defects can generate similar signals. As a result, chemists may have been misassigning some peaks and overlooking opportunities to tailor the properties of such materials by deliberately introducing defects.<\/p>\n

Carbon-based materials, such as carbon fibre, graphene and carbon nanotubes, are used in fuel cells, insulation, aerospace engineering and many other applications. Their specific properties depend on atomic structure, including the type and distribution of defects.<\/p>\n

\u2018Understanding the nature of these defects provides valuable insight into how they influence the properties and functionality of carbon materials,\u2019 says computational chemist Jean-Sabin McEwen<\/a> at Washington State University in the US, who was not involved in the work. He explains that defects can impact catalyst activity, selectivity and reaction mechanisms.<\/p>\n

Techniques like Raman, infrared and x-ray photoelectron spectroscopy help chemists identify imperfections in a material\u2019s structure. However, researchers in Japan are now suggesting that some peaks in certain spectra may have been previously misassigned.<\/p>\n

The team, based at Chiba University, first computationally analysed a variety of graphene-based materials with various defects using density functional theory (DFT). Comparing the simulated spectra to experimental data from carbon materials made at 1200\u00b0C or above revealed that certain results could have multiple origins, rather than arising from a single defect.<\/p>\n

For example, a peak at around 285eV in x-ray photoelectron spectra is generally thought to signal electrons in the 1s orbital of an sp3 carbon, likely from adventitious carbon not in the structure itself. \u2018However, our calculations demonstrate that [the peak] actually originates from [sp2] carbon atoms surrounded by structures containing seven-membered, eight-membered and vacancy defects,\u2019 says Yasuhiro Yamada<\/a>, who led the work.<\/p>\n

\u2018Researchers would routinely cite established papers and interpret [the peak] as sp\u00b3 carbon almost as an automatic reflex, without critical re-evaluation,\u2019 he says, \u2018because there were almost no [other] reported assignments.\u2019 He notes, for example, that certain C\u2013N bond energies can overlap with the sp3 carbon peak.\u00a0<\/p>\n

\u2018If defects have been misassigned, computational models based on those assignments may lead to incorrect conclusions,\u2019 says McEwen, adding that previous studies \u2018may need to be revisited and reinterpreted.\u2019<\/p>\n

\"Annotated<\/p>\n

However, he points out that the models that the team uses do not include periodic boundary conditions. \u2018The absence of [these conditions] could influence the calculated binding energies and vibrational properties, particularly for extended graphitic systems,\u2019 he says.<\/p>\n

As for the Raman spectra, the team unveiled the origin of peaks that overlap between 1500 and 1500cm-1, which had previously been challenging to identify. Analysis revealed that carbon\u2013carbon double bonds near to cyclic ethers and non-hexagonal rings could generate signals in this region. The team was able to figure this out by deconvoluting the broad peak into \u2018as many as 17 distinct peaks\u2019, says Yamada, which could then be compared to computational predictions.<\/p>\n

Being able to fully assign peaks in spectra is not just an academic pursuit; it could also help chemists design better materials. Yamada\u2019s team has done this, for example, by controlling the degree and position of nitrogen-doping in carbon materials to increase selectivity for carbon dioxide capture.2 Yamada also notes that \u2018the insights gained in the study are by no means limited to the specific carbon fibres\u2019 that the team analysed: \u2018They can be widely applied as a fundamental guideline for analysing and interpreting the [spectra] of various [carbon materials].\u2019<\/p>\n","protected":false},"excerpt":{"rendered":"Certain peaks in the spectra of carbon-based materials can arise from multiple defects, researchers have concluded after computational…\n","protected":false},"author":2,"featured_media":584354,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[85,46,141],"class_list":["post-584353","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-il","tag-israel","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/584353","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=584353"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/584353\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/584354"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=584353"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=584353"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=584353"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}