One of Spain’s most highly cited chemists, Rafael Luque, has been suspended by the University of Córdoba, reportedly for 13 years. The suspension was a consequence of taking positions at other institutions without permission, according to Luque.

Since 2019, Luque has listed King Saud University in Saudi Arabia as his primary affiliation, while keeping his position in Spain. This resulted in a sharp drop in the position of the University of Córdoba in the Shanghai Ranking, an index that aims to measure the quality of higher education institutions.

After the news of his suspension appeared in El País, many researchers raised concerns about Luque’s work. The number of publications he has authored is unusually high, and includes a large fraction of sporadic co-authors, and the quality of dozens of his articles has been questioned.

Before his suspension, Luque was a reader at the University of Córdoba, where he has spent most of his academic career. His research interests include biomass and waste valorisation, as well as nanoscale chemistry. From 2018 to 2022, Luque was listed as a highly cited researcher by Clarivate.

In 2018, Luque became director of a laboratory at RUDN University in Russia, while still holding his position at Córdoba. After that he also became a professor at Xi´an Jiaotong University in China, and at King Saud University in Saudi Arabia.

Under Spanish law, tenured professors are public servants and are only allowed to take additional jobs with the permission of their university. Luque says he was denied permission as a result of ‘irreconcilable differences with the University of Córdoba’s president’s team’. The university confirmed Luque is no longer ‘providing services’ to the institution, but declined to comment further, citing privacy concerns.

Luque is among several highly cited researchers, many of them in Spain, who have switched their primary affiliations to universities in Saudi Arabia in recent years, according to a report by the Barcelona-based research consultancy Siris Academic. In 2019 Luque changed his main affiliation from Córdoba to King Saud University, according to Clarivate, the company that puts together the highly cited researchers ranking that is used to calculate the Shanghai Ranking. As a result, the University of Córdoba lost about 150 positions, dropping from 616th to 767th in the world, according to Siris’s calculations.

Productivity questions

In the last decade, Luque’s productivity has rocketed, and Scopus lists him as the author of over 100 papers and review articles in 2022 – an average of two publications per week, excluding proceedings, book chapters and other publications. Being an author on many publications tends to be more common in research involving large consortia, like particle physics or health. But many believe they raise a red flag in chemistry. ‘This overproduction is absurd. There are areas [of chemistry] where there is a very clear publishing inflation,’ says Antonio Echavarren, president of the Spanish Royal Society of Chemistry (RSEQ ).

‘We need a debate on authorship and how you run a [research] group. [Principal investigators] with dozens of workers sign everything [the workers do]. They may run the team and contribute ideas, but it’s debatable whether that should be treated as authorship,’ says Francois-Xavier Coudert, a researcher at the Paris Chemistry Research Institute.

Luque’s group is not especially large. According to bibliometric researcher Ángel M Delgado Vázquez at the University Pablo de Olavide in Spain, Luque has a long list of sporadic collaborations, some of them with authors in countries including Pakistan, China, Brazil, Ecuador and Vietnam. Out of over 1600 co-authors, less than 20 have co-signed 25 or more papers with him.

Ross Mounce, director of open access programmes at the Arcadia Fund, a UK charity that promotes access to knowledge, says the case ‘calls into question what publishers are doing to prevent “guest” and “gift” authorships’. Guest or gift authorships are where the author of a paper recruits scientists from more prominent institutions to become an author on their paper, in exchange for money or minimal participation. This can boost the publication rate or increase the ranking of the institution of both parties.

Beyond the sheer volume of Luque’s publications, questions have also been raised about its quality. In the last year, Luque’s work has received dozens of critical comments on post-publication review website PubPeer. The allegations include duplicated images, self-citation, self-plagiarism and even a paper whose authorship was allegedly offered on the messaging platform Telegram.

Luque has acknowledged criticism and promised to tackle problems, but in most cases the papers have not been retracted or corrected.

Nick Wise, an engineer at the University of Cambridge who has commented on Luque’s work on PubPeer, suspects the University of Córdoba may have used the breaching of contract as a quick way to deal with concerns over Luque’s work. Delgado, on the other hand, asks why Luque has been singled out, given that that several other Spanish chemists have similar rates of productivity.

The University of Córdoba did not clarify whether its research integrity committee would investigate Luque’s work. Echavarren says the RSEQ is set to discuss whether Luque will remain on its energy commission at the end of this month.