How Reproducible Are Surface Areas Calculated from the BET Equation?
Authors: Osterrieth Johannes , Rampersad James , Madden David G. , Rampal Nakul , Skoric Luka , Connolly Bethany , Allendorf Mark , Stavila Vitalie , SNIDER JONATHAN , Ameloot Rob , Marreiros Joao , Ania Conchi O. , Azevedo Diana C. S. , Vilarrasa-García Enrique , Santos Bianca F , Bu Xian-He , Zang Xe , Bunzen Hana , Champness Neil , Griffin Sarah L. , Chen Banglin , Lin Rui-Biao , Coasne Benoit , Cohen Seth M. , Moreton Jessica C. , Colon Yamil J. , Chen Linjiang , Clowes Rob , Coudert François-Xavier , Cui Yong , Hou Bang , D’Alessandro Deanna , Doheny Patrick W. , Dinca Mircea , Sun Chenyue , Doonan Christian , Huxley Michael , Evans Jack D. , falcaro paolo , Riccò Raffaele , Farha Omar K. , Idrees Karam B. , Islamoglu Timur , Feng Pingyun , Yang Huajun , Forgan Ross , Bara Dominic , Furukawa Shuhei , Sanchez Elisabeth , Gascon Jorge , Telalovic Selvedin , Ghosha Sujit K. , MUKHERJEE SOUMYA , Hill Matthew R. , Sadiq Muhammad Munir , Horcajada Patricia , Salcedo-Abraira Pablo , Kaneko Katsumi , Kukobat Radovan , Kenvin Jeffrey , Keskin Seda , Kitagawa Susumu , Otake Kenichi , Lively Ryan P. , DeWitt Stephen J. A. , Llewellyn Philip L. , Lotsch Bettina , Emmerling Sebastian T. , Pütz Alexander , Martí-Gastaldo Carlos , Muñoz Natalia , Garcia-Martinez Javier , Linares Noemi , Maspoch Daniel , Suarez Jose Antonio , Moghadam Peyman , Oktavian Rama , Morris Russell , Wheatley Paul , Navarro Jorge , Petit Camille , Danaci David , Rosseinsky Matthew , Katsoulidis Alexandros , Schroder Martin , Han Xue , Yang Sihai , Serre Christian , Mouchaham Georges , Sholl David , Thyagarajan Raghuram , Siderius Daniel , Snurr Randall Q. , Goncalves Rebecca B. , Telfer Shane G. , Lee Seok J. , Ting Valeska , Rowlandson Jemma , Uemura Takeshi , Iiyuka Tomoya , van der Veen Monique , Rega Davide , Vanspeybroeck Veronique , Lamaire Aran , Rogge Sven , Walton Krista , Bingel Lukas W. , Wuttke Stefan , Andreo Jacopo , Yaghi Omar , Zhang Bing , Yavuz Cafer , Nguyen Thien , Zamora Felix , Montoro Carmen , Zhou Hong-Cai , Angelo Kirchon , Fairen-Jimenez David 
Published: February 2022

Porosity and surface area analysis play a prominent role in modern materials science, where their determination spans the fields of natural sciences, engineering, geology and medical research. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory,[1] which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro- and mesoporous materials.[2] Since the BET method was first developed, there has been an explosion in the field of nanoporous materials with the discovery of synthetic zeolites,[3] nanostructured silicas,[4–6] metal-organic frameworks (MOFs),[7] and others. Despite its widespread use, the manual calculation of BET surface areas causes a significant spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, we have brought together 60 labs with strong track records on the study of nanoporous materials. We provided eighteen already measured raw adsorption isotherms and asked these researchers to calculate the corresponding BET areas. This round-robin exercise resulted in a wide range of values for each isotherm. We demonstrate here that the reproducibility of BET area determination from identical isotherms is a largely ignored issue, raising critical concerns over the reliability of reported BET areas in micro- and mesoporous materials in the literature. To solve this major issue, we have developed a new computational approach to accurately and systematically determine the BET area of nanoporous materials. Our software, called BET Surface Identification (BETSI), expands on the well-known Rouquerol criteria and makes, for the first time, an unambiguous BET area assignment possible.